1
00:00:01,700 --> 00:00:07,166
♪♪

2
00:00:07,200 --> 00:00:12,666
♪♪

3
00:00:12,700 --> 00:00:15,466
{\an1}-Think about it...

4
00:00:15,500 --> 00:00:18,200
{\an1}when you're sitting still
and not breathing...

5
00:00:21,566 --> 00:00:23,500
{\an1}...what is the only thing
in your body

6
00:00:23,533 --> 00:00:26,333
{\an1}that's palpably moving?

7
00:00:28,466 --> 00:00:32,333
{\an1}-Every second, your body
gives you a little sign

8
00:00:32,366 --> 00:00:34,433
{\an1}to prove that it's still there.

9
00:00:34,466 --> 00:00:41,833
♪♪

10
00:00:41,866 --> 00:00:44,166
A pulse.

11
00:00:44,200 --> 00:00:47,966
{\an1}-It is billions of cells

12
00:00:48,000 --> 00:00:52,766
{\an1}beating for billions of times
in a lifetime,

13
00:00:52,800 --> 00:00:55,066
{\an1}never pausing to rest.

14
00:00:59,566 --> 00:01:03,333
{\an1}-Behind that beat is an
unbelievably vast system

15
00:01:03,366 --> 00:01:05,200
{\an1}whose one and only job

16
00:01:05,233 --> 00:01:09,100
{\an1}is to make sure every cell
in your body stays alive.

17
00:01:09,133 --> 00:01:15,566
♪♪

18
00:01:15,600 --> 00:01:18,100
-The speed,

19
00:01:18,133 --> 00:01:21,000
the strength,

20
00:01:21,033 --> 00:01:22,733
the frequency,

21
00:01:22,766 --> 00:01:25,833
the rhythm --

22
00:01:25,866 --> 00:01:28,666
{\an1}it tells us so much.

23
00:01:28,700 --> 00:01:31,733
{\an1}-A heart that thumps...

24
00:01:31,766 --> 00:01:34,333
{\an1}blood that flows through
thousands of miles

25
00:01:34,366 --> 00:01:35,866
{\an1}of arteries and veins...

26
00:01:39,033 --> 00:01:42,700
{\an1}All so we can attempt
the crazy feats

27
00:01:42,733 --> 00:01:44,433
{\an1}that make humans...

28
00:01:44,466 --> 00:01:46,400
unique.

29
00:01:46,433 --> 00:01:55,933
♪♪

30
00:01:55,966 --> 00:02:05,566
♪♪

31
00:02:05,600 --> 00:02:15,100
♪♪

32
00:02:15,133 --> 00:02:21,400
{\an1}Human life depends on one
substance above all others --

33
00:02:21,433 --> 00:02:24,500
oxygen.

34
00:02:24,533 --> 00:02:27,766
{\an1}We can go about three weeks
without food,

35
00:02:27,800 --> 00:02:31,433
{\an1}three days without water.

36
00:02:31,466 --> 00:02:34,633
{\an1}But without oxygen, we wouldn't
last three minutes.

37
00:02:37,933 --> 00:02:40,800
But why?

38
00:02:40,833 --> 00:02:42,666
{\an1}Well, if you think about it,

39
00:02:42,700 --> 00:02:45,000
{\an1}each of us is just
a huge pile of cells,

40
00:02:45,033 --> 00:02:48,600
{\an1}somewhere around 37 trillion.

41
00:02:48,633 --> 00:02:52,666
{\an1}Blood cells, skin cells,
brain cells.

42
00:02:55,700 --> 00:02:57,566
{\an1}And every single one
of those cells

43
00:02:57,600 --> 00:03:01,233
{\an1}contains an engine
that runs on oxygen.

44
00:03:04,066 --> 00:03:07,566
{\an1}Think of it like a fire
that's always burning.

45
00:03:07,600 --> 00:03:09,833
{\an1}Oxygen is the wood or coal.

46
00:03:13,100 --> 00:03:17,466
{\an1}And to keep the fire stoked,
all we have to do is breathe in.

47
00:03:17,500 --> 00:03:23,300
{\an1}But getting a supply of oxygen
is the easy part.

48
00:03:23,333 --> 00:03:25,166
{\an1}Once it's inside the body,

49
00:03:25,200 --> 00:03:28,366
{\an1}all that fuel has to somehow
find its way

50
00:03:28,400 --> 00:03:32,800
{\an1}into those 37 trillion engines.

51
00:03:32,833 --> 00:03:36,400
{\an1}And that requires a system
that never rests.

52
00:03:37,833 --> 00:03:40,633
{\an7}-The cardiovascular
and circulatory systems

53
00:03:40,666 --> 00:03:46,133
{\an7}represent our major engine
in our bodies.

54
00:03:46,166 --> 00:03:49,133
{\an1}Now, this is to make sure
that all of our cells

55
00:03:49,166 --> 00:03:52,033
{\an1}have oxygen going in,

56
00:03:52,066 --> 00:03:55,900
{\an1}carbon dioxide leaving,

57
00:03:55,933 --> 00:03:58,200
{\an1}plenty of nutrients,

58
00:03:58,233 --> 00:04:00,233
{\an1}and essentially keeps us going.

59
00:04:03,500 --> 00:04:06,733
{\an8}-The body itself
is pretty small,

60
00:04:06,766 --> 00:04:11,233
{\an7}but the network of vessels
is enormous.

61
00:04:11,266 --> 00:04:14,466
{\an1}The vessels themselves
laid end-to-end would be

62
00:04:14,500 --> 00:04:17,066
{\an1}about 100,000 miles long,

63
00:04:17,100 --> 00:04:21,033
{\an1}which would encircle the globe
probably four times.

64
00:04:21,066 --> 00:04:25,966
{\an1}-This vast network of pumps,
valves, and tunnels

65
00:04:26,000 --> 00:04:29,966
{\an1}delivers oxygen to cells
in every corner of your body,

66
00:04:30,000 --> 00:04:33,566
{\an1}without you ever having
to think about it.

67
00:04:33,600 --> 00:04:37,733
{\an1}And what's more insane than that
is we can train this system

68
00:04:37,766 --> 00:04:41,466
{\an1}to work even more efficiently.

69
00:04:41,500 --> 00:04:44,966
{\an1}Especially when oxygen
is harder to come by.

70
00:04:52,833 --> 00:04:58,366
♪♪

71
00:04:58,400 --> 00:05:02,000
{\an1}-It would be difficult
to sum me up in one word

72
00:05:02,033 --> 00:05:06,366
because I'm a bit
of a contradiction.

73
00:05:06,400 --> 00:05:09,600
On one hand,
I'm a Southern Belle,

74
00:05:09,633 --> 00:05:13,133
a debutante,
and afraid of heights.

75
00:05:15,133 --> 00:05:18,700
{\an1}But I'm also an extreme
alpinist, an ice climber,

76
00:05:18,733 --> 00:05:20,300
{\an1}and a rock climber.

77
00:05:20,333 --> 00:05:27,633
{\an8}♪♪

78
00:05:27,666 --> 00:05:29,600
{\an7}My name is Kitty Calhoun.

79
00:05:29,633 --> 00:05:31,966
{\an7}Ice climbing is who I am.

80
00:05:34,066 --> 00:05:37,833
{\an1}-High-altitude ice climbing
is the ultimate test

81
00:05:37,866 --> 00:05:41,466
{\an1}for the cardiovascular system.

82
00:05:41,500 --> 00:05:45,033
{\an1}Imagine you're scaling
a vertical slab of ice.

83
00:05:48,400 --> 00:05:51,966
{\an1}Your body is screaming
for oxygen to feed your muscles

84
00:05:52,000 --> 00:05:55,533
{\an1}to keep moving upwards.

85
00:05:55,566 --> 00:05:57,366
{\an1}It's true that any elite athlete

86
00:05:57,400 --> 00:06:02,866
{\an1}has to have an extremely
efficient cardiovascular system.

87
00:06:02,900 --> 00:06:06,266
{\an1}But climbing is different.

88
00:06:06,300 --> 00:06:10,366
{\an1}The air at high altitudes
is depleted of oxygen

89
00:06:10,400 --> 00:06:11,900
{\an1}and freezing temperatures tax

90
00:06:11,933 --> 00:06:14,866
{\an1}a system that's already
pushed to the brink.

91
00:06:14,900 --> 00:06:20,266
♪♪

92
00:06:20,300 --> 00:06:22,766
{\an1}Then add in one last factor --

93
00:06:22,800 --> 00:06:25,933
{\an1}the heart-pounding knowledge
that at any moment,

94
00:06:25,966 --> 00:06:27,566
you could slip.

95
00:06:29,966 --> 00:06:32,366
Training to climb
means teaching the body

96
00:06:32,400 --> 00:06:36,266
{\an1}to adapt to an atmosphere that
can barely sustain human life.

97
00:06:38,533 --> 00:06:43,266
{\an1}And that training begins
in one place -- the heart.

98
00:06:47,700 --> 00:06:51,833
{\an1}-The heart is the first organ
to start functioning

99
00:06:51,866 --> 00:06:54,933
{\an1}and is typically the last one

100
00:06:54,966 --> 00:06:59,400
{\an1}to stop functioning
in the human lifetime.

101
00:07:01,200 --> 00:07:03,000
{\an1}-It's only the size of a fist,

102
00:07:03,033 --> 00:07:08,133
{\an1}but it beats more than
100,000 times a day.

103
00:07:08,166 --> 00:07:10,633
The heart itself
is just two pumps

104
00:07:10,666 --> 00:07:12,466
side-by-side.

105
00:07:12,500 --> 00:07:15,500
{\an1}On the left, the tricuspid
valve collects blood

106
00:07:15,533 --> 00:07:17,666
{\an1}from all over the body.

107
00:07:17,700 --> 00:07:20,633
{\an1}On the right, the pulmonary
valve takes that blood

108
00:07:20,666 --> 00:07:23,633
{\an1}and shoots it into the organ
that surrounds the heart.

109
00:07:26,033 --> 00:07:27,666
The lungs.

110
00:07:31,533 --> 00:07:33,933
{\an1}There, the blood picks up oxygen

111
00:07:33,966 --> 00:07:37,800
{\an1}from tiny air-filled sacs
called alveoli

112
00:07:37,833 --> 00:07:41,133
{\an1}that expand like balloons
every time we inhale.

113
00:07:44,666 --> 00:07:47,300
Then it goes back
to the heart

114
00:07:47,333 --> 00:07:49,633
{\an1}so that all that oxygen-rich
blood can get pumped

115
00:07:49,666 --> 00:07:52,400
{\an1}to the rest of the body.

116
00:07:52,433 --> 00:07:55,300
{\an1}After a minute, it returns,

117
00:07:55,333 --> 00:07:58,100
{\an1}ready for another trip.

118
00:07:58,133 --> 00:08:03,066
{\an1}That cycle happens
every second of every day.

119
00:08:03,100 --> 00:08:06,033
{\an1}But throw a mountain
into the mix,

120
00:08:06,066 --> 00:08:08,033
{\an1}and things get interesting.

121
00:08:08,066 --> 00:08:17,533
♪♪

122
00:08:17,566 --> 00:08:19,066
{\an1}-Ice climbing is an activity

123
00:08:19,100 --> 00:08:22,333
{\an1}where you have to be
in good cardio shape.

124
00:08:22,366 --> 00:08:24,066
{\an1}When I'm not ice climbing,

125
00:08:24,100 --> 00:08:27,266
{\an1}I'm getting a good cardio work
in a short amount of time.

126
00:08:29,266 --> 00:08:32,200
{\an1}-In order for Kitty's heart
to perform well on the ice,

127
00:08:32,233 --> 00:08:34,200
{\an1}she needs to train it
to pump blood

128
00:08:34,233 --> 00:08:36,233
{\an1}as dynamically as possible.

129
00:08:38,766 --> 00:08:41,166
-During exercise,
there are a lot of changes

130
00:08:41,200 --> 00:08:45,400
that occur in our
cardiovascular system.

131
00:08:45,433 --> 00:08:48,266
{\an1}The heart obviously speeds up.

132
00:08:48,300 --> 00:08:52,233
{\an1}The more beats per minute,
the more blood flow

133
00:08:52,266 --> 00:08:53,866
{\an1}out of the heart per minute,

134
00:08:53,900 --> 00:08:57,566
{\an1}therefore the more oxygen
delivery to the tissues.

135
00:08:59,700 --> 00:09:03,766
{\an1}The efficiency of oxygen
transfer also increases

136
00:09:03,800 --> 00:09:08,166
{\an1}so that muscles can use
the oxygen more efficiently.

137
00:09:10,966 --> 00:09:13,933
{\an1}-Consistently exercising
the heart muscle

138
00:09:13,966 --> 00:09:17,966
{\an1}trains it to push more blood out
with each beat,

139
00:09:18,000 --> 00:09:20,400
{\an1}which means it doesn't
need to beat as often.

140
00:09:23,133 --> 00:09:25,933
{\an1}-The human heart is like
any other part

141
00:09:25,966 --> 00:09:29,766
of our biology --
highly adaptive.

142
00:09:29,800 --> 00:09:32,400
{\an7}The more demands that are placed
on our heart,

143
00:09:32,433 --> 00:09:36,866
{\an7}the more the heart responds
in terms of its capacity.

144
00:09:36,900 --> 00:09:40,366
{\an1}Over time, you'll find
the resting heart rate

145
00:09:40,400 --> 00:09:42,766
{\an1}of a marathon runner
would be much lower

146
00:09:42,800 --> 00:09:46,466
{\an1}than that of a person
who is much more sedentary.

147
00:09:49,766 --> 00:09:51,933
{\an1}-Kitty has trained her heart
to withstand

148
00:09:51,966 --> 00:09:56,966
{\an1}the physical stresses of a climb
up a solid sheet of ice.

149
00:09:57,000 --> 00:10:00,833
{\an1}But in this sport, there's more
than just exhaustion at stake.

150
00:10:02,966 --> 00:10:05,633
{\an1}If you're hanging by an axe
from a cliff,

151
00:10:05,666 --> 00:10:10,366
{\an1}your heart is also being
challenged by something else --

152
00:10:10,400 --> 00:10:11,733
fear.

153
00:10:11,766 --> 00:10:14,266
{\an1}-You know, there's risk in life,
right?

154
00:10:14,300 --> 00:10:17,900
{\an1}If you don't step out the door,
then you won't get hit by a car.

155
00:10:17,933 --> 00:10:19,466
{\an1}If you don't go ice climbing,

156
00:10:19,500 --> 00:10:22,766
{\an1}then you won't have
an accident ice climbing.

157
00:10:24,800 --> 00:10:29,100
{\an1}Risk is something that people
try to shut out in their lives,

158
00:10:29,133 --> 00:10:31,933
{\an1}and I think to live life fully,

159
00:10:31,966 --> 00:10:34,200
{\an1}to experience all that
life has to give,

160
00:10:34,233 --> 00:10:36,866
that what you
have to do is minimize the risk

161
00:10:36,900 --> 00:10:40,566
{\an1}by getting experience
and making good decisions.

162
00:10:40,600 --> 00:10:47,966
♪♪

163
00:10:48,000 --> 00:10:55,366
♪♪

164
00:10:55,400 --> 00:10:59,700
I do feel fear,
standing down at the bottom

165
00:10:59,733 --> 00:11:02,500
{\an1}and looking up at the climb.

166
00:11:02,533 --> 00:11:06,466
{\an1}I still have a healthy fear
of falling.

167
00:11:06,500 --> 00:11:09,833
{\an1}So one of the biggest tricks
that I use

168
00:11:09,866 --> 00:11:12,633
{\an1}to keep it together mentally
is breathing.

169
00:11:12,666 --> 00:11:18,933
♪♪

170
00:11:18,966 --> 00:11:24,000
{\an1}-When the system runs amuck
like in a panic attack,

171
00:11:24,033 --> 00:11:25,300
{\an1}the heart speeds up,

172
00:11:25,333 --> 00:11:27,500
the heart pumps
less efficiently,

173
00:11:27,533 --> 00:11:32,633
{\an1}and is less able to meet the
metabolic demands of the body.

174
00:11:32,666 --> 00:11:35,033
{\an1}So an ice climber, for example,

175
00:11:35,066 --> 00:11:39,600
{\an1}would have to get control
of that response,

176
00:11:39,633 --> 00:11:43,366
{\an1}to slow down their heartbeat
and enable the heart

177
00:11:43,400 --> 00:11:47,366
to fill properly
and pump blood more efficiently.

178
00:11:51,333 --> 00:11:56,266
{\an1}-Climbing is as much mental
as it is physical.

179
00:11:56,300 --> 00:11:58,466
{\an1}As Kitty's heart has transformed
over time

180
00:11:58,500 --> 00:12:01,233
{\an1}to be able to handle
the extreme conditions,

181
00:12:01,266 --> 00:12:02,866
so has her brain.

182
00:12:05,033 --> 00:12:08,066
{\an1}-I start climbing,
and I'm focused on breathing

183
00:12:08,100 --> 00:12:11,033
and making sure
that I work my feet up high

184
00:12:11,066 --> 00:12:16,333
{\an1}and then push up off my legs
like you're doing a squat.

185
00:12:16,366 --> 00:12:18,266
{\an1}And when you do pull
with your arms,

186
00:12:18,300 --> 00:12:23,033
{\an1}you really try to use your back
as much as you can.

187
00:12:23,066 --> 00:12:25,766
{\an1}Everything is a balance.

188
00:12:25,800 --> 00:12:30,066
{\an1}-It's all a highly
coordinated dance.

189
00:12:30,100 --> 00:12:32,200
{\an1}The mind keeps everything
in check

190
00:12:32,233 --> 00:12:35,733
{\an1}while muscles all over the body
reach their limit,

191
00:12:35,766 --> 00:12:38,200
{\an1}in constant need of more oxygen.

192
00:12:41,066 --> 00:12:43,000
{\an1}Kitty's well-trained heart

193
00:12:43,033 --> 00:12:45,400
{\an1}handles all these tasks easily.

194
00:12:47,900 --> 00:12:49,533
The hard part

195
00:12:49,566 --> 00:12:52,066
{\an1}is getting the supply of oxygen
in the first place.

196
00:12:55,233 --> 00:12:56,733
{\an1}At high altitudes,

197
00:12:56,766 --> 00:13:01,100
{\an1}the atmosphere contains
a lot less oxygen.

198
00:13:01,133 --> 00:13:04,133
{\an1}That means there's less fuel
for red blood cells to extract

199
00:13:04,166 --> 00:13:07,266
{\an1}from the air entering the lungs.

200
00:13:07,300 --> 00:13:08,933
{\an1}If you've ever been
up that high,

201
00:13:08,966 --> 00:13:13,333
{\an1}you know how heavy
your breathing gets.

202
00:13:13,366 --> 00:13:16,266
{\an1}To try and compensate,
the heart goes into overdrive

203
00:13:16,300 --> 00:13:18,666
to pump the blood
to starving muscles.

204
00:13:20,766 --> 00:13:22,433
{\an1}The low levels of oxygen
in the blood

205
00:13:22,466 --> 00:13:25,000
{\an1}can cause headaches and fatigue

206
00:13:25,033 --> 00:13:27,633
{\an1}as the body tries to function
with less fuel.

207
00:13:30,500 --> 00:13:32,933
{\an1}It can also affect the mind.

208
00:13:36,100 --> 00:13:40,300
{\an1}-Every organ depends
on the heart for its function.

209
00:13:40,333 --> 00:13:45,933
{\an1}The brain cannot function
without a moving heart.

210
00:13:45,966 --> 00:13:49,833
-Without oxygen,
the brain gets foggy.

211
00:13:49,866 --> 00:13:51,733
{\an1}That's another reason
spending too much time

212
00:13:51,766 --> 00:13:54,166
{\an1}up in the clouds is dangerous.

213
00:13:54,200 --> 00:13:56,766
{\an1}Your judgment goes right out
the window.

214
00:13:56,800 --> 00:14:03,700
♪♪

215
00:14:03,733 --> 00:14:07,166
But once again,
Kitty's body is different.

216
00:14:07,200 --> 00:14:09,366
{\an1}Her red blood cells
are better at adjusting

217
00:14:09,400 --> 00:14:11,800
{\an1}to the changing atmosphere,

218
00:14:11,833 --> 00:14:14,900
{\an1}which gives her the edge
she needs to get to the top.

219
00:14:14,933 --> 00:14:21,733
♪♪

220
00:14:21,766 --> 00:14:28,533
♪♪

221
00:14:28,566 --> 00:14:30,833
-Yay! Oh, man.

222
00:14:30,866 --> 00:14:33,433
It feels good.

223
00:14:37,566 --> 00:14:41,833
{\an1}When I'm at the top, I feel
a sense of relief for sure,

224
00:14:41,866 --> 00:14:45,066
{\an1}a sense of accomplishment.

225
00:14:45,100 --> 00:14:47,533
{\an1}Climbing is a form of therapy
for me

226
00:14:47,566 --> 00:14:52,800
{\an1}because I can just escape,
and I enjoy breathing hard,

227
00:14:52,833 --> 00:14:55,900
{\an1}I enjoy the strength
aspect of it,

228
00:14:55,933 --> 00:15:00,533
{\an1}I enjoy just moving
in a different way.

229
00:15:00,566 --> 00:15:05,966
♪♪

230
00:15:06,000 --> 00:15:11,433
♪♪

231
00:15:11,466 --> 00:15:15,466
{\an1}-This frozen ice face melts
when the seasons change...

232
00:15:20,666 --> 00:15:22,900
{\an1}...leading streams
into rivers...

233
00:15:25,000 --> 00:15:28,300
{\an1}that snake through the landscape
and bring life.

234
00:15:32,266 --> 00:15:35,800
{\an1}Humans use these waterways
for transport and trade.

235
00:15:37,900 --> 00:15:41,566
{\an1}We construct cities around them.

236
00:15:41,600 --> 00:15:45,733
{\an1}They hold spiritual
meaning for us.

237
00:15:45,766 --> 00:15:48,533
{\an1}The constant flow of water
through rivers

238
00:15:48,566 --> 00:15:51,600
{\an1}has supported life
for millennia,

239
00:15:51,633 --> 00:15:53,566
much like
the labyrinth intertwined

240
00:15:53,600 --> 00:15:55,633
{\an1}right underneath our skin.

241
00:15:55,666 --> 00:16:01,266
♪♪

242
00:16:01,300 --> 00:16:04,666
{\an1}-Because our blood
has to be conveyed

243
00:16:04,700 --> 00:16:06,966
{\an1}to every cell in the body,

244
00:16:07,000 --> 00:16:11,100
{\an1}the enormity of the blood
vessels in our body

245
00:16:11,133 --> 00:16:14,633
{\an1}is really mind-boggling.

246
00:16:14,666 --> 00:16:18,666
{\an1}-A lot of simpler life forms
don't need a circulatory system

247
00:16:18,700 --> 00:16:21,333
{\an1}because they're just one-cell
beings and they can rely

248
00:16:21,366 --> 00:16:25,600
{\an1}on the diffusion of molecules
within their one cell

249
00:16:25,633 --> 00:16:28,300
{\an1}to carry everything around
that they need to.

250
00:16:28,333 --> 00:16:33,666
{\an1}But we as humans are made up
of many cells,

251
00:16:33,700 --> 00:16:38,800
{\an1}and we needed to evolve a system
that would allow us

252
00:16:38,833 --> 00:16:44,300
{\an1}to very efficiently move oxygen
throughout our body.

253
00:16:47,533 --> 00:16:49,300
{\an1}-Over the course of a day,

254
00:16:49,333 --> 00:16:52,166
{\an1}blood will travel about
12,000 miles

255
00:16:52,200 --> 00:16:53,866
{\an1}through arteries and veins.

256
00:16:56,966 --> 00:17:01,566
{\an1}It's a system defined
by constant motion,

257
00:17:01,600 --> 00:17:05,333
{\an1}something that's also reflected
in our evolution as a species.

258
00:17:05,366 --> 00:17:14,033
♪♪

259
00:17:14,066 --> 00:17:15,433
{\an1}-Humans are absolutely
built to move.

260
00:17:15,466 --> 00:17:16,766
{\an1}I mean, if you look
at our ancestry

261
00:17:16,800 --> 00:17:18,600
{\an1}and the way we used
to move around,

262
00:17:18,633 --> 00:17:23,866
{\an1}our musculoskeletal system
is designed for us to be agile,

263
00:17:23,900 --> 00:17:27,033
{\an1}to go long periods
of time by moving,

264
00:17:27,066 --> 00:17:29,033
{\an1}and our hearts can perfectly
accommodate this

265
00:17:29,066 --> 00:17:32,300
{\an1}by making sure we get the right
amount of blood when we need it.

266
00:17:34,533 --> 00:17:36,833
{\an1}-But here's the tricky thing --

267
00:17:36,866 --> 00:17:40,200
{\an1}not only does our circulatory
system allow us to move,

268
00:17:40,233 --> 00:17:43,466
{\an1}it only works properly
if we are moving.

269
00:17:47,100 --> 00:17:50,500
{\an1}For most of us, modern life
doesn't involve hunting

270
00:17:50,533 --> 00:17:54,433
{\an1}or crossing continents on foot.

271
00:17:54,466 --> 00:17:56,700
{\an1}And what we're finding out
is that if we stay still

272
00:17:56,733 --> 00:18:01,333
for too long,
the whole system breaks down.

273
00:18:01,366 --> 00:18:06,600
{\an8}♪♪

274
00:18:06,633 --> 00:18:11,933
{\an8}♪♪

275
00:18:20,466 --> 00:18:28,133
♪♪

276
00:18:28,166 --> 00:18:33,266
{\an1}-Driving a bus, you're just
sitting there driving.

277
00:18:33,300 --> 00:18:35,500
Day in, day out,
eight-hour shift.

278
00:18:38,866 --> 00:18:40,466
{\an1}Sometimes if you're really busy,

279
00:18:40,500 --> 00:18:42,666
{\an1}you may spend your
entire shift in the seat

280
00:18:42,700 --> 00:18:45,966
{\an1}because you're running behind
schedule or something.

281
00:18:46,000 --> 00:18:50,833
♪♪

282
00:18:50,866 --> 00:18:52,833
{\an1}You're sitting in traffic,
sometimes you might sit

283
00:18:52,866 --> 00:18:55,400
in the seat
for three hours in traffic.

284
00:18:55,433 --> 00:18:58,966
{\an1}Again, you're not moving.

285
00:18:59,000 --> 00:19:03,900
{\an1}The advice I give people
is just you gotta be moving.

286
00:19:03,933 --> 00:19:06,566
{\an1}If you're going to sit down,
you're going to die.

287
00:19:09,566 --> 00:19:11,166
{\an1}I'm a prime example.

288
00:19:13,866 --> 00:19:16,533
{\an8}I'm Steve Dean,
and I drive a city bus.

289
00:19:16,566 --> 00:19:24,000
{\an8}♪♪

290
00:19:24,033 --> 00:19:25,900
{\an1}-I think one of the life lessons
that the cells

291
00:19:25,933 --> 00:19:30,966
{\an1}I've studied has taught me
is this concept of

292
00:19:31,000 --> 00:19:32,866
{\an1}if you don't use it,
you lose it.

293
00:19:32,900 --> 00:19:34,366
{\an1}Cells know what they're doing,

294
00:19:34,400 --> 00:19:38,700
{\an1}but they need to be challenged.

295
00:19:38,733 --> 00:19:41,366
{\an1}-One of the biggest obstacles
our circulation is up against

296
00:19:41,400 --> 00:19:45,866
{\an1}is something that we have
absolutely no control over --

297
00:19:45,900 --> 00:19:47,500
gravity.

298
00:19:50,100 --> 00:19:52,066
{\an1}Humans are an upright species.

299
00:19:52,100 --> 00:19:55,066
{\an1}We walk on two legs.

300
00:19:55,100 --> 00:19:58,066
{\an1}So once our blood has traveled
down the arteries

301
00:19:58,100 --> 00:20:02,700
{\an1}and unloaded oxygen to all
the cells below the heart,

302
00:20:02,733 --> 00:20:05,866
{\an1}that same blood then has to move
straight upwards again

303
00:20:05,900 --> 00:20:09,033
{\an1}through our veins to get back
to where it started,

304
00:20:09,066 --> 00:20:11,733
working against
Earth's gravitational pull

305
00:20:11,766 --> 00:20:14,566
the entire time.

306
00:20:14,600 --> 00:20:16,033
In most cases,

307
00:20:16,066 --> 00:20:19,333
{\an1}arteries rely on the heart
to pump blood,

308
00:20:19,366 --> 00:20:23,666
{\an1}but veins have to get their
power from another source --

309
00:20:23,700 --> 00:20:25,700
muscles.

310
00:20:25,733 --> 00:20:29,400
{\an1}When you tense your leg muscles
they propel blood upwards.

311
00:20:31,200 --> 00:20:33,500
{\an1}But this ingenious adaptation
only works

312
00:20:33,533 --> 00:20:35,466
{\an1}if the muscles are active.

313
00:20:35,500 --> 00:20:38,866
{\an1}Otherwise, the pumps have
no energy to work with.

314
00:20:41,333 --> 00:20:44,700
{\an1}Think about sitting
for long periods of time.

315
00:20:44,733 --> 00:20:47,466
Your leg muscles
aren't doing anything,

316
00:20:47,500 --> 00:20:49,866
{\an1}so they can't pump that blood
back to the heart

317
00:20:49,900 --> 00:20:52,466
{\an1}with any real force.

318
00:20:52,500 --> 00:20:55,200
And that can lead
to major problems.

319
00:20:59,233 --> 00:21:00,933
{\an1}-A bus driver's heart,

320
00:21:00,966 --> 00:21:03,700
{\an1}cruising through traffic
with no issue,

321
00:21:03,733 --> 00:21:05,933
{\an1}is beating at a resting pace.

322
00:21:05,966 --> 00:21:08,866
{\an1}There is no sense of urgency
to increase a heart rate

323
00:21:08,900 --> 00:21:11,700
{\an1}and throw more blood
to the body.

324
00:21:11,733 --> 00:21:14,900
{\an1}-You're very sedentary
when you're driving the coach.

325
00:21:14,933 --> 00:21:17,433
{\an1}You sit there a lot.

326
00:21:17,466 --> 00:21:19,066
{\an1}And that's kind of one
of the downfalls

327
00:21:19,100 --> 00:21:22,333
{\an1}of driving the coach.

328
00:21:24,166 --> 00:21:27,066
Back in 2010,

329
00:21:27,100 --> 00:21:28,733
{\an1}when I was working a lot,

330
00:21:28,766 --> 00:21:31,733
{\an1}just sitting there driving,

331
00:21:31,766 --> 00:21:36,466
{\an1}I was up to about 250,
260 pounds.

332
00:21:36,500 --> 00:21:40,600
I felt sluggish.

333
00:21:40,633 --> 00:21:44,200
{\an1}-Our jobs have never been
more stationary.

334
00:21:44,233 --> 00:21:48,066
{\an1}They've moved from farms
to cities,

335
00:21:48,100 --> 00:21:50,566
{\an1}and now onto the Internet.

336
00:21:50,600 --> 00:21:52,900
{\an1}And we're constantly
told to exercise,

337
00:21:52,933 --> 00:21:58,466
{\an1}because the damage
can creep up on you, silently.

338
00:21:58,500 --> 00:22:04,133
{\an1}-On general inspection,
the heart of a sedentary person

339
00:22:04,166 --> 00:22:06,366
{\an1}might look normal.

340
00:22:06,400 --> 00:22:10,333
{\an1}However, if you probe more
deeply and look, for example,

341
00:22:10,366 --> 00:22:14,966
{\an1}at the arteries that supply
blood to the heart muscle,

342
00:22:15,000 --> 00:22:18,300
it's more likely
that those arteries

343
00:22:18,333 --> 00:22:21,633
{\an1}would have more signs
of fatty deposits,

344
00:22:21,666 --> 00:22:27,366
{\an1}in part because of
the sedentary lifestyle.

345
00:22:27,400 --> 00:22:31,866
{\an1}-Not moving actually makes the
body worse at processing fat.

346
00:22:31,900 --> 00:22:33,466
{\an1}And probably everyone on earth

347
00:22:33,500 --> 00:22:36,666
will tell you
that fat is the enemy.

348
00:22:36,700 --> 00:22:38,700
And here's why --

349
00:22:38,733 --> 00:22:41,966
it's really just
a matter of space.

350
00:22:42,000 --> 00:22:47,033
{\an1}When we exercise, the arteries
surrounding the heart expand.

351
00:22:47,066 --> 00:22:50,300
When we don't,
they get thinner.

352
00:22:50,333 --> 00:22:54,166
{\an1}And blood needs room to move.

353
00:22:54,200 --> 00:22:58,966
{\an1}-A river can get blocked
by rocks, for example.

354
00:22:59,000 --> 00:23:03,033
{\an1}Similarly blood vessels
can develop blockages,

355
00:23:03,066 --> 00:23:05,100
{\an1}called atherosclerosis,

356
00:23:05,133 --> 00:23:07,433
{\an1}which are essentially
fatty deposits

357
00:23:07,466 --> 00:23:09,400
{\an1}that start at the wall

358
00:23:09,433 --> 00:23:11,600
{\an1}and start to protrude inward

359
00:23:11,633 --> 00:23:13,733
and eventually
impede blood flow.

360
00:23:13,766 --> 00:23:19,033
♪♪

361
00:23:19,066 --> 00:23:21,366
-These blockages
that build over time

362
00:23:21,400 --> 00:23:24,033
{\an1}can get us into real trouble.

363
00:23:24,066 --> 00:23:27,733
{\an1}-I felt this burning
in my chest.

364
00:23:27,766 --> 00:23:30,400
I drove myself to
St. Peter's emergency room.

365
00:23:30,433 --> 00:23:32,466
They did an EKG.

366
00:23:36,233 --> 00:23:39,533
{\an1}The doctor, she said,
"You've had a heart attack."

367
00:23:39,566 --> 00:23:44,866
♪♪

368
00:23:44,900 --> 00:23:48,000
{\an1}-The heart not only pumps blood
to the entire body,

369
00:23:48,033 --> 00:23:51,333
{\an1}but it also pumps blood
to itself.

370
00:23:51,366 --> 00:23:53,566
{\an1}It's self-sustaining.

371
00:23:53,600 --> 00:23:57,200
{\an1}No other organ does that.

372
00:23:57,233 --> 00:24:02,133
{\an1}The heart is so hard-working
that it needs a constant supply

373
00:24:02,166 --> 00:24:06,100
{\an1}of oxygen and nutrients
to remain functional.

374
00:24:08,166 --> 00:24:12,666
{\an1}When those arteries get
clogged up with fatty deposits,

375
00:24:12,700 --> 00:24:15,600
{\an1}that can result in
stoppage of blood flow

376
00:24:15,633 --> 00:24:18,933
{\an1}to the heart muscle.

377
00:24:18,966 --> 00:24:21,100
{\an1}And when that heart muscle dies,

378
00:24:21,133 --> 00:24:24,300
{\an1}that's called a heart attack.

379
00:24:24,333 --> 00:24:28,133
{\an1}-And unlike other muscles,
heart cells barely regenerate.

380
00:24:30,266 --> 00:24:34,800
{\an1}When they die, scar tissue
grows in their place,

381
00:24:34,833 --> 00:24:37,466
{\an1}and scar tissue can't pump.

382
00:24:40,700 --> 00:24:44,900
{\an1}-It was the very tip
of an artery that was blocked.

383
00:24:44,933 --> 00:24:46,466
{\an1}They said, "If you'd have
went to sleep,

384
00:24:46,500 --> 00:24:49,900
{\an1}you might not have woke up."

385
00:24:49,933 --> 00:24:52,600
{\an1}You know, it's an eye-opening
experience.

386
00:24:52,633 --> 00:24:55,733
{\an1}I just realized my time
on this earth now has a limit

387
00:24:55,766 --> 00:24:57,400
{\an1}and made me realize

388
00:24:57,433 --> 00:24:59,966
{\an1}that I need to do things
in my life different.

389
00:25:02,833 --> 00:25:05,533
{\an1}Gosh, we're just about here.

390
00:25:08,733 --> 00:25:10,500
{\an1}Well, I drive Dial-A-Lift now.

391
00:25:10,533 --> 00:25:12,566
Good morning.
-Good morning.

392
00:25:12,600 --> 00:25:14,366
{\an1}-How are you today?

393
00:25:14,400 --> 00:25:17,033
Dial-A-Lift
is a door-to-door service

394
00:25:17,066 --> 00:25:21,300
{\an1}for passengers with disabilities
or elderly,

395
00:25:21,333 --> 00:25:25,766
{\an1}something that prevents them
from riding the normal bus.

396
00:25:28,033 --> 00:25:31,166
{\an1}-Marianne is my first
rider today.

397
00:25:31,200 --> 00:25:33,966
I take her to
the Sacred Heart Church.

398
00:25:34,000 --> 00:25:35,366
{\an1}-Is this an express?

399
00:25:35,400 --> 00:25:37,500
{\an1}-Yup, you're going
straight there today.

400
00:25:37,533 --> 00:25:40,233
-Oh, good.
That works for me.

401
00:25:40,266 --> 00:25:43,033
{\an1}-I probably added another 3,000

402
00:25:43,066 --> 00:25:46,733
{\an1}to 4,000 steps a day
by driving Dial-A-Lift.

403
00:25:46,766 --> 00:25:48,300
{\an1}Good morning. It's Dial-A-Lift.

404
00:25:48,333 --> 00:25:49,700
{\an1}You're out of the seat,

405
00:25:49,733 --> 00:25:52,000
{\an1}and then you escort them out
to the van.

406
00:25:52,033 --> 00:25:54,333
After you.
I'll have you go on board there.

407
00:25:54,366 --> 00:25:56,400
{\an1}You get them on the lift
on the van.

408
00:25:56,433 --> 00:25:57,966
Okay, up we go.

409
00:25:58,000 --> 00:26:00,300
{\an1}And this step's a little higher.

410
00:26:00,333 --> 00:26:02,800
{\an1}Sometimes you have your arm out
for them to hold on

411
00:26:02,833 --> 00:26:04,600
{\an1}so they're steady.

412
00:26:04,633 --> 00:26:06,533
{\an1}It's things like that
that keep you healthy.

413
00:26:06,566 --> 00:26:09,600
{\an1}-Well, here we are.
-Yeah, get to go work out.

414
00:26:09,633 --> 00:26:13,266
-Yay!
Hey, that's good for you.

415
00:26:13,300 --> 00:26:15,100
Well, you have
a wonderful day today.

416
00:26:15,133 --> 00:26:17,633
{\an1}-Do you feel like a celebrity?
[ Laughs ]

417
00:26:17,666 --> 00:26:20,266
{\an1}-I feel like Steve, as always.

418
00:26:24,566 --> 00:26:27,466
{\an1}-If you don't need
a strong heart,

419
00:26:27,500 --> 00:26:29,233
{\an1}your body won't give you one.

420
00:26:29,266 --> 00:26:31,600
If you don't need
strong muscles,

421
00:26:31,633 --> 00:26:33,233
{\an1}why would your body make one?

422
00:26:33,266 --> 00:26:36,966
{\an1}So it's in a way like if
you don't use it, you lose it.

423
00:26:37,000 --> 00:26:40,766
{\an1}But if you use it, you get it.
[ Laughs ]

424
00:26:40,800 --> 00:26:43,600
{\an1}It's been really exciting for me
to see this in practice,

425
00:26:43,633 --> 00:26:47,433
{\an1}you know, with people who are
experiencing the increase

426
00:26:47,466 --> 00:26:50,366
in strength
that can come about so quickly

427
00:26:50,400 --> 00:26:52,566
{\an1}just by exercising
and giving ourselves

428
00:26:52,600 --> 00:26:54,233
{\an1}a little bit of a challenge.

429
00:26:54,266 --> 00:26:57,066
To me, it's just
very life affirming

430
00:26:57,100 --> 00:27:01,000
{\an1}to think that at any age,
we always have the opportunity

431
00:27:01,033 --> 00:27:04,700
{\an1}to adapt and to do better.

432
00:27:04,733 --> 00:27:11,333
{\an8}♪♪

433
00:27:11,366 --> 00:27:13,466
[ Heart beating ]

434
00:27:13,500 --> 00:27:17,466
{\an1}-The heart and vessels are
a mind-bendingly vast system.

435
00:27:20,200 --> 00:27:24,200
{\an1}But to operate, they need blood.

436
00:27:24,233 --> 00:27:27,700
-I mean it's not
for nothing that we refer

437
00:27:27,733 --> 00:27:29,966
{\an1}to the metaphorical life blood

438
00:27:30,000 --> 00:27:35,133
{\an1}because the blood is literally
the life giving fluid.

439
00:27:35,166 --> 00:27:36,866
What is blood?

440
00:27:36,900 --> 00:27:40,300
{\an1}Blood is essentially composed
of two substances.

441
00:27:40,333 --> 00:27:42,000
{\an1}One is the plasma,

442
00:27:42,033 --> 00:27:47,500
{\an1}which is basically salts,
water, and proteins.

443
00:27:47,533 --> 00:27:50,833
{\an1}And the other part is the cells.

444
00:27:53,333 --> 00:27:55,966
{\an1}-Red blood cells account
for more than 80%

445
00:27:56,000 --> 00:27:58,466
{\an1}of all of our cells,

446
00:27:58,500 --> 00:28:03,033
and the other 20%
rely on them to survive.

447
00:28:03,066 --> 00:28:05,166
{\an1}1 million times every minute,

448
00:28:05,200 --> 00:28:09,100
{\an1}red blood cells absorb
the oxygen we need to live.

449
00:28:10,366 --> 00:28:13,866
{\an1}-It's an extraordinary piece
of our physiology.

450
00:28:13,900 --> 00:28:19,066
{\an1}Our heart pumps out five
to six liters of blood a minute,

451
00:28:19,100 --> 00:28:23,266
{\an1}and that blood is constantly
being circulated around the body

452
00:28:23,300 --> 00:28:26,900
{\an1}with new oxygen that's
breathed in every few seconds

453
00:28:26,933 --> 00:28:29,166
{\an1}with waste products
that are being cleaned out

454
00:28:29,200 --> 00:28:31,033
{\an1}on that same time scale.

455
00:28:31,066 --> 00:28:35,066
{\an1}It powers our every moment
of our day-to-day lives.

456
00:28:38,800 --> 00:28:41,400
{\an1}-Their never-ending job
has given red blood cells

457
00:28:41,433 --> 00:28:44,033
{\an1}a unique structure.

458
00:28:44,066 --> 00:28:47,066
{\an1}Unlike other cells,
they don't have a nucleus.

459
00:28:49,300 --> 00:28:51,433
{\an1}Instead, they're filled
with massive quantities

460
00:28:51,466 --> 00:28:53,700
of a protein
called hemoglobin.

461
00:28:57,233 --> 00:29:01,900
{\an1}It's made of iron,
which is why blood is red.

462
00:29:01,933 --> 00:29:05,433
{\an1}Hemoglobin grabs on to
the oxygen we breathe in,

463
00:29:05,466 --> 00:29:08,933
{\an1}then, at the right moment,
it lets go,

464
00:29:08,966 --> 00:29:12,266
{\an1}and oxygen molecules pass
into the surrounding cells.

465
00:29:14,966 --> 00:29:19,266
{\an1}What's crazy is that hemoglobin
is toxic to the human body.

466
00:29:19,300 --> 00:29:23,400
{\an1}If it escaped from even a tiny
fraction of our red blood cells,

467
00:29:23,433 --> 00:29:26,333
it could kill us,
but as long as it stays

468
00:29:26,366 --> 00:29:30,566
{\an1}within the cells walls,
it can't harm us.

469
00:29:30,600 --> 00:29:35,133
{\an1}Red blood cells have a margin
error of exactly zero

470
00:29:35,166 --> 00:29:38,600
and they do
their job perfectly.

471
00:29:38,633 --> 00:29:41,233
{\an1}That is, as long as there's
enough blood in the body

472
00:29:41,266 --> 00:29:42,433
to go around.

473
00:29:42,466 --> 00:29:45,233
[ Siren wailing ]

474
00:29:45,266 --> 00:29:47,466
{\an1}Because when we lose blood,

475
00:29:47,500 --> 00:29:51,500
{\an1}everything is then
in jeopardy,

476
00:29:51,533 --> 00:29:53,900
{\an1}and just a few minutes can mean
the difference

477
00:29:53,933 --> 00:29:56,733
{\an1}between life and death.

478
00:29:56,766 --> 00:30:03,800
{\an8}♪♪

479
00:30:03,833 --> 00:30:10,900
{\an8}♪♪

480
00:30:10,933 --> 00:30:13,500
[ Horns honking ]

481
00:30:13,533 --> 00:30:18,100
{\an1}The city of Accra is home
to 2 million people.

482
00:30:18,133 --> 00:30:21,833
{\an1}It's Ghana's capital,
its beating heart.

483
00:30:21,866 --> 00:30:25,366
{\an8}♪♪

484
00:30:30,800 --> 00:30:34,300
{\an1}150 miles away over
rugged terrain

485
00:30:34,333 --> 00:30:36,266
{\an1}is the tiny town of Asissinwa.

486
00:30:39,800 --> 00:30:42,933
{\an1}A place so remote that
the word "emergency"

487
00:30:42,966 --> 00:30:45,033
{\an1}takes on a whole new meaning.

488
00:30:48,100 --> 00:30:50,466
{\an1}[ Man speaking native language ]

489
00:30:53,166 --> 00:30:56,200
{\an1}-One plus two is three.

490
00:31:02,566 --> 00:31:04,333
Hello!

491
00:31:23,733 --> 00:31:27,700
{\an1}-The bond between mother
and her child is profound,

492
00:31:27,733 --> 00:31:30,700
{\an1}and it starts in the womb.

493
00:31:30,733 --> 00:31:34,566
{\an1}The first thing they share
is blood.

494
00:31:34,600 --> 00:31:36,300
{\an1}-The fetus doesn't breathe.

495
00:31:36,333 --> 00:31:41,533
{\an1}It's floating in amniotic fluid,
and it only receives

496
00:31:41,566 --> 00:31:44,366
oxygen through
the mother's blood supply

497
00:31:44,400 --> 00:31:46,233
{\an1}through the umbilical cord.

498
00:31:46,266 --> 00:31:51,000
{\an1}The mother's blood supply also
ferries waste out of the fetus,

499
00:31:51,033 --> 00:31:54,333
{\an1}which then gets cleared
by the mother's kidneys.

500
00:31:56,366 --> 00:31:59,700
{\an1}-It's an amazing exchange,
but it also means

501
00:31:59,733 --> 00:32:02,933
{\an1}that when something
goes wrong with one,

502
00:32:02,966 --> 00:32:04,933
{\an1}both are in danger.

503
00:32:09,666 --> 00:32:12,400
[ Woman speaking
native language ]

504
00:32:12,966 --> 00:32:15,533
{\an1}-[ Speaking native language ]

505
00:32:15,566 --> 00:32:18,100
{\an1}It will not be safe.

506
00:32:18,133 --> 00:32:21,300
{\an8}-I'm Dr. Phillip
Agyeman-Prempeh.

507
00:32:21,333 --> 00:32:25,966
{\an7}I'm an obstetrician/gynecologist
at Saint Michael Hospital.

508
00:32:26,000 --> 00:32:31,000
{\an1}We make over 2,000 deliveries
every year in this facility.

509
00:33:12,866 --> 00:33:18,100
-Akua Nyarko came
into our maternity emergency.

510
00:33:18,133 --> 00:33:22,300
{\an1}She was at 36 weeks plus
4 weeks in her pregnancy.

511
00:33:23,066 --> 00:33:25,633
{\an1}The abdomen felt very tense,

512
00:33:25,666 --> 00:33:28,966
{\an1}and we could not hear
the fetal heart rate,

513
00:33:29,000 --> 00:33:32,000
{\an1}both with the Doppler
and ultrasound.

514
00:33:34,633 --> 00:33:37,633
{\an7}-During the birthing process,
the mom and the baby

515
00:33:37,666 --> 00:33:39,833
{\an8}are going through
huge amounts of changes

516
00:33:39,866 --> 00:33:44,033
{\an7}that affect the physical aspects
of both infant and mother.

517
00:33:44,066 --> 00:33:45,933
Immediately after
the baby is born,

518
00:33:45,966 --> 00:33:49,000
{\an1}the uterus will contract
to allow all of those

519
00:33:49,033 --> 00:33:51,766
{\an1}blood vessels that have been
opened during the pregnancy

520
00:33:51,800 --> 00:33:54,266
so that the woman
actually does not hemorrhage,

521
00:33:54,300 --> 00:33:57,333
{\an1}meaning she does not continue
to bleed too heavily.

522
00:33:58,500 --> 00:34:01,766
{\an1}-For Akua, something
had gone very wrong.

523
00:34:03,900 --> 00:34:06,400
{\an1}-The uterus was not contracting.

524
00:34:06,433 --> 00:34:09,533
{\an1}She was bleeding profusely,

525
00:34:09,566 --> 00:34:14,733
and we realized
that her blood was not clotting.

526
00:34:14,766 --> 00:34:18,333
{\an1}-We lose blood all the time --
in small doses,

527
00:34:18,366 --> 00:34:22,066
{\an1}and our bodies can handle it.

528
00:34:22,100 --> 00:34:24,766
{\an1}But if there's a major bleed
that isn't stopping,

529
00:34:24,800 --> 00:34:28,000
{\an1}the body can't recover.

530
00:34:28,033 --> 00:34:30,900
{\an1}The response has to be
lightning fast,

531
00:34:30,933 --> 00:34:34,033
{\an1}and that means a transfusion.

532
00:34:35,366 --> 00:34:39,200
{\an1}-We needed blood to stabilize
her and save her life.

533
00:34:39,233 --> 00:34:42,266
But we realized
we didn't have enough blood.

534
00:34:44,233 --> 00:34:48,600
{\an1}-And getting blood into
a remote area can take hours.

535
00:34:49,900 --> 00:34:53,866
{\an1}-In cases like this,
we would ask for an ambulance

536
00:34:53,900 --> 00:34:59,233
{\an1}to bring us the products,
but that takes time.

537
00:34:59,266 --> 00:35:02,133
It was a dilemma
and a tough one.

538
00:35:02,166 --> 00:35:04,933
So we called our
biomedical scientist,

539
00:35:04,966 --> 00:35:10,166
{\an1}and he made an order
for us to get blood.

540
00:35:10,200 --> 00:35:14,566
{\an1}-Meanwhile the body starts
its own rescue effort fast

541
00:35:14,600 --> 00:35:16,766
{\an1}by sending messages.

542
00:35:16,800 --> 00:35:19,333
{\an1}-We have little brains
all over our body,

543
00:35:19,366 --> 00:35:22,966
and the heart
has a pretty big one.

544
00:35:23,000 --> 00:35:24,766
{\an1}It's been recently discovered

545
00:35:24,800 --> 00:35:29,033
{\an1}that there are about
40,000 neurons on the heart.

546
00:35:30,166 --> 00:35:33,000
{\an1}Nerves that go to the brain
as well as nerves

547
00:35:33,033 --> 00:35:35,233
{\an1}that come from the brain.

548
00:35:35,266 --> 00:35:37,466
{\an1}It's very responsive.

549
00:35:37,500 --> 00:35:41,466
{\an1}It has the capacity to
beat faster or slower

550
00:35:41,500 --> 00:35:44,966
{\an1}to be able to best serve
the needs of the body

551
00:35:45,000 --> 00:35:47,100
{\an1}at any given time.

552
00:35:48,600 --> 00:35:51,433
{\an1}-This group of neurons
reacts immediately

553
00:35:51,466 --> 00:35:54,733
{\an1}when blood leaves the body.

554
00:35:54,766 --> 00:35:58,133
{\an1}Pressure sensors on
the heart perceive the loss,

555
00:35:58,166 --> 00:36:00,833
and they tell
the nervous system.

556
00:36:00,866 --> 00:36:02,500
{\an1}It sends out signals

557
00:36:02,533 --> 00:36:06,900
{\an1}that start a chain reaction
to keep cells alive.

558
00:36:06,933 --> 00:36:09,033
It's a highly
synchronized effort

559
00:36:09,066 --> 00:36:11,833
that depends on
instant communication.

560
00:36:11,866 --> 00:36:15,666
{\an1}Much like the technology that
Akua's doctors used to contact

561
00:36:15,700 --> 00:36:18,533
{\an1}the only people who could
send them blood

562
00:36:18,566 --> 00:36:20,233
{\an1}in time to save her life.

563
00:36:20,266 --> 00:36:26,500
{\an8}♪♪

564
00:36:26,533 --> 00:36:30,000
-Emergency. Okay.
We'll get it to you right away.

565
00:36:30,033 --> 00:36:32,333
{\an8}♪♪

566
00:36:32,366 --> 00:36:34,000
[ Bell dings ]

567
00:36:34,033 --> 00:36:42,466
{\an8}♪♪

568
00:36:42,500 --> 00:36:50,966
{\an8}♪♪

569
00:36:51,000 --> 00:36:59,400
{\an8}♪♪

570
00:36:59,433 --> 00:37:04,066
{\an1}-We had to perform
an emergency cesarean section

571
00:37:04,100 --> 00:37:06,233
to stabilize her,
and then to prevent her

572
00:37:06,266 --> 00:37:08,766
{\an1}from losing more blood.

573
00:37:08,800 --> 00:37:12,033
This is a patient
who was very pale.

574
00:37:12,066 --> 00:37:15,900
{\an1}If we didn't get the blood,
it was highly likely

575
00:37:15,933 --> 00:37:18,266
{\an1}that she would bleed to death.

576
00:37:24,833 --> 00:37:28,033
{\an1}-Very little in the body
can happen without blood.

577
00:37:28,066 --> 00:37:32,466
{\an1}If you empty the heart of blood
and stopped it, then the brain

578
00:37:32,500 --> 00:37:34,800
and the kidneys
and the vital organs

579
00:37:34,833 --> 00:37:38,200
{\an1}wouldn't get oxygen and you'd
develop massive organ damage

580
00:37:38,233 --> 00:37:41,266
within a period
of three minutes.

581
00:37:41,300 --> 00:37:46,766
{\an1}The blood is the conduit for all
these other organs to function.

582
00:37:49,400 --> 00:37:51,766
{\an1}-If cells go without oxygen
for too long,

583
00:37:51,800 --> 00:37:56,200
the body goes
into irreversible shock.

584
00:37:56,233 --> 00:37:59,366
{\an1}But the heart-brain knows
when it's in trouble,

585
00:37:59,400 --> 00:38:01,866
{\an1}and its response is smart.

586
00:38:04,666 --> 00:38:07,466
{\an1}The heart starts to beat faster.

587
00:38:07,500 --> 00:38:10,833
Breathing becomes
shallow and quick.

588
00:38:10,866 --> 00:38:13,700
There's also
a chemical reaction.

589
00:38:13,733 --> 00:38:16,933
{\an1}Hormones flood blood vessels
in the skin

590
00:38:16,966 --> 00:38:19,166
{\an1}causing them to constrict.

591
00:38:20,633 --> 00:38:25,133
{\an1}Blood moves inward
to keep vital organs alive.

592
00:38:25,166 --> 00:38:28,333
{\an1}That's why people turn pale
when they lose blood.

593
00:38:30,200 --> 00:38:33,366
{\an1}Skin is not so important,

594
00:38:33,400 --> 00:38:36,566
{\an1}but the brain is vital.

595
00:38:39,000 --> 00:38:42,500
{\an1}It's the body's clever way
of redistributing resources.

596
00:38:45,966 --> 00:38:48,466
If the blood loss
is really extreme,

597
00:38:48,500 --> 00:38:51,033
{\an1}it might be impossible
to reverse the damage.

598
00:38:53,333 --> 00:38:56,333
Tragically
for Akua's unborn child,

599
00:38:56,366 --> 00:38:58,866
{\an1}it was already too late.

600
00:39:01,600 --> 00:39:05,233
{\an1}But Akua was still holding on.

601
00:39:05,266 --> 00:39:17,700
{\an8}♪♪

602
00:39:17,733 --> 00:39:21,900
{\an1}-Within 20 minutes,
Zipline brought us the blood.

603
00:39:21,933 --> 00:39:26,500
{\an1}We started transfusing her.

604
00:39:26,533 --> 00:39:30,133
{\an1}And then she was able
to pull through.

605
00:39:46,300 --> 00:39:50,500
{\an1}-With some support,
the body begins to stabilize.

606
00:39:50,533 --> 00:39:54,100
{\an1}-Our bodies evolved
the cardiovascular system

607
00:39:54,133 --> 00:39:59,533
{\an1}to ramp up very, very quickly
and ramp down

608
00:39:59,566 --> 00:40:03,766
{\an1}because we can't maintain
a degree of stress

609
00:40:03,800 --> 00:40:07,300
{\an1}for long periods of time
without damaging the system.

610
00:40:32,766 --> 00:40:35,033
{\an1}-The connection between
the brain and the heart

611
00:40:35,066 --> 00:40:38,400
{\an1}is complex and not one-sided.

612
00:40:42,900 --> 00:40:45,000
{\an1}The structures in the brain
regulate the heart

613
00:40:45,033 --> 00:40:47,866
{\an1}through nerve impulses
and hormones,

614
00:40:47,900 --> 00:40:49,400
{\an1}and it's in the brain
that emotions

615
00:40:49,433 --> 00:40:51,733
{\an1}and thoughts are processed,

616
00:40:51,766 --> 00:40:54,866
{\an1}even though sometimes
it doesn't seem that way.

617
00:40:54,900 --> 00:40:58,533
{\an1}-Anyone who's ever experienced
a sense of panic

618
00:40:58,566 --> 00:41:02,766
{\an1}knows that we feel it
immediately in our heart.

619
00:41:02,800 --> 00:41:04,800
{\an1}So why would it be a surprise

620
00:41:04,833 --> 00:41:07,333
that the heart
would be really smart

621
00:41:07,366 --> 00:41:11,433
{\an1}at being connected
to our emotional state

622
00:41:11,466 --> 00:41:16,500
{\an1}when that is our internalized
experience of the outside world.

623
00:41:17,600 --> 00:41:19,766
{\an1}-So if we feel things
in our heart,

624
00:41:19,800 --> 00:41:23,100
does that mean
it has a mind of its own?

625
00:41:23,133 --> 00:41:26,833
{\an1}-The idea that the heart
might be telling the brain

626
00:41:26,866 --> 00:41:29,066
{\an1}how to think or how to feel

627
00:41:29,100 --> 00:41:31,600
{\an1}is an open question
for me personally

628
00:41:31,633 --> 00:41:36,666
{\an1}and one that I think is very
hotly debated among scientists.

629
00:41:36,700 --> 00:41:39,600
{\an1}-If there are neurons
on the heart,

630
00:41:39,633 --> 00:41:41,933
{\an1}then maybe its power
over our emotions

631
00:41:41,966 --> 00:41:45,633
{\an1}isn't just poetic,
but also biological.

632
00:41:46,500 --> 00:41:56,233
{\an8}♪♪

633
00:41:56,266 --> 00:42:06,033
{\an8}♪♪

634
00:42:06,066 --> 00:42:15,833
{\an8}♪♪

635
00:42:31,266 --> 00:42:35,200
{\an8}♪♪

636
00:42:35,233 --> 00:42:37,733
{\an7}-My name is Bertha Martinez.

637
00:42:37,766 --> 00:42:43,866
{\an7}I am a volunteer at the
Lincoln Heights Senior Center.

638
00:42:43,900 --> 00:42:45,633
After we retired,

639
00:42:45,666 --> 00:42:50,333
{\an1}my husband and I started
helping at the center.

640
00:42:50,366 --> 00:42:53,633
{\an1}We love to dance, and we have
been attending there

641
00:42:53,666 --> 00:42:56,200
{\an1}for the past 18 years.

642
00:42:58,233 --> 00:43:00,366
-Hombres!

643
00:43:00,400 --> 00:43:03,266
[ Cheering ]

644
00:43:03,300 --> 00:43:06,933
{\an1}-We always say that
it's our second family.

645
00:43:07,166 --> 00:43:09,566
-Buenos dias.

646
00:43:09,600 --> 00:43:11,966
{\an1}[ Speaking Spanish ]

647
00:43:12,000 --> 00:43:13,600
{\an1}-Humans are social animals.

648
00:43:13,633 --> 00:43:15,600
{\an1}-[ Speaking Spanish ]

649
00:43:15,633 --> 00:43:19,100
{\an1}-That's something that we share
with primates in general.

650
00:43:19,133 --> 00:43:21,466
{\an7}We live in groups,
and a lot of the way

651
00:43:21,500 --> 00:43:22,800
{\an8}that we navigate
the world around us,

652
00:43:22,833 --> 00:43:25,000
{\an8}has to do with
social relationships.

653
00:43:28,166 --> 00:43:31,300
{\an1}This is something that
is reflected in our biology.

654
00:43:36,000 --> 00:43:37,866
{\an1}-The brain and the heart
are connected

655
00:43:37,900 --> 00:43:41,466
{\an1}by the most powerful
neural network in the body,

656
00:43:41,500 --> 00:43:44,933
the vagus nerve.

657
00:43:44,966 --> 00:43:49,300
{\an1}It passes millions of messages
back and forth every day.

658
00:43:49,333 --> 00:43:52,033
The vast majority
come not from the brain

659
00:43:52,066 --> 00:43:55,066
{\an1}but from the heart.

660
00:43:56,233 --> 00:43:59,500
{\an1}And this network is responsible
for communicating emotions

661
00:44:02,400 --> 00:44:05,500
{\an1}Positive social interactions
light up the vagus nerve

662
00:44:05,533 --> 00:44:08,766
and the heart.

663
00:44:08,800 --> 00:44:10,500
In other words,
our relationships

664
00:44:10,533 --> 00:44:13,566
{\an1}are constantly shaping
our internal worlds.

665
00:44:22,566 --> 00:44:24,933
{\an1}-This is my husband Ricardo.

666
00:44:24,966 --> 00:44:30,700
{\an1}This picture was taken
on our 25th wedding anniversary.

667
00:44:32,333 --> 00:44:36,433
{\an1}I lost my husband last year.

668
00:44:36,466 --> 00:44:42,700
{\an1}This chair, my husband used it
all the time to watch TV.

669
00:44:46,533 --> 00:44:49,533
{\an1}Someone told me why
don't I take everything down

670
00:44:49,566 --> 00:44:52,433
{\an1}so that way I cannot
feel so bad?

671
00:44:52,466 --> 00:44:55,066
But to me,
it's just the opposite.

672
00:44:59,633 --> 00:45:02,566
{\an1}-We know that people
who experience intense

673
00:45:02,600 --> 00:45:07,600
{\an1}emotional disturbance like grief
after the death of a loved one

674
00:45:07,633 --> 00:45:10,766
or the breakup of
a romantic relationship

675
00:45:10,800 --> 00:45:15,900
{\an1}can develop severe effects
on their hearts.

676
00:45:17,566 --> 00:45:21,900
{\an1}The heart in these people
tends to acutely weaken

677
00:45:21,933 --> 00:45:27,266
and change shape
into the shape of a takotsubo,

678
00:45:27,300 --> 00:45:33,433
{\an1}which is a Japanese pot with
a narrow neck and a wide base.

679
00:45:33,466 --> 00:45:36,600
{\an1}It's been variably called
the broken heart syndrome

680
00:45:36,633 --> 00:45:40,066
{\an1}or takotsubo cardiomyopathy,

681
00:45:40,100 --> 00:45:42,900
and we know
that emotional stress

682
00:45:42,933 --> 00:45:46,033
{\an1}can accelerate the development
of heart disease

683
00:45:46,066 --> 00:45:48,866
{\an1}and increase the risk
of cardiac mortality.

684
00:45:51,900 --> 00:45:55,733
{\an1}-The exact cause is unknown.

685
00:45:55,766 --> 00:45:58,433
{\an1}Our best guess is that
a super dose of adrenaline

686
00:45:58,466 --> 00:46:00,933
floods the heart,
shocking cardiac cells

687
00:46:00,966 --> 00:46:02,966
{\an1}and weakening them.

688
00:46:06,333 --> 00:46:08,900
{\an1}Hormones like adrenaline
are one of the main ways

689
00:46:08,933 --> 00:46:12,000
{\an1}the brain communicates
with the heart,

690
00:46:12,033 --> 00:46:13,833
and the risk
of developing takotsubo

691
00:46:13,866 --> 00:46:16,166
{\an1}might have something to do with
the strength

692
00:46:16,200 --> 00:46:20,266
{\an1}of neural connections and how
they respond to stress.

693
00:46:22,533 --> 00:46:25,833
{\an1}The same regions in the brain
that regulate your heartbeat

694
00:46:25,866 --> 00:46:28,933
{\an1}have been linked to emotional
conditions like depression.

695
00:46:31,200 --> 00:46:32,966
{\an1}But unlike a heart attack,

696
00:46:33,000 --> 00:46:37,433
the cardiac cells
are just shocked, not lost.

697
00:46:37,466 --> 00:46:41,000
{\an1}-Fortunately for us, a lot of
the injury to the heart

698
00:46:41,033 --> 00:46:43,233
{\an1}is potentially reversible.

699
00:46:43,266 --> 00:46:45,966
{\an1}The heart does tend
to self-correct,

700
00:46:46,000 --> 00:46:49,000
{\an1}so when our emotional states
return to normal,

701
00:46:49,033 --> 00:46:52,366
the heart itself
can also return to normal.

702
00:46:57,033 --> 00:46:58,933
{\an8}-Okay.

703
00:46:58,966 --> 00:47:04,200
{\an7}-I think it's very important to
come out, even when you're sad.

704
00:47:06,433 --> 00:47:11,200
{\an7}-There is a kind of
takotsubo cardiomyopathy,

705
00:47:11,233 --> 00:47:13,633
{\an1}or broken heart syndrome,
that occurs after

706
00:47:13,666 --> 00:47:19,266
{\an1}happy events, too, but the heart
shape changes differently.

707
00:47:21,166 --> 00:47:25,033
{\an1}-In the same way that adrenaline
can damage cardiac cells,

708
00:47:25,066 --> 00:47:28,333
{\an1}there are other hormones that
can have the opposite effect.

709
00:47:28,366 --> 00:47:30,733
{\an1}And there's one molecule
that's most associated

710
00:47:30,766 --> 00:47:35,000
with the complex
social behavior of humans --

711
00:47:35,033 --> 00:47:39,733
{\an1}oxytocin, often called
the love hormone.

712
00:47:39,766 --> 00:47:43,133
{\an1}Think about the feeling you get
when you hug a friend or dance

713
00:47:43,166 --> 00:47:45,666
{\an1}with a flirty stranger.

714
00:47:45,700 --> 00:47:49,333
That rush comes
as oxytocin spikes

715
00:47:49,366 --> 00:47:52,733
{\an1}and makes a beeline
for the heart.

716
00:47:52,766 --> 00:47:55,300
{\an1}Just like fear can make
your heart pound,

717
00:47:55,333 --> 00:48:00,733
{\an1}the oxytocin released by touch
can put your heart at rest.

718
00:48:00,766 --> 00:48:04,066
{\an1}Receptors on cardiac cells
detect its presence

719
00:48:04,100 --> 00:48:06,866
{\an1}and your heart rate slows.

720
00:48:06,900 --> 00:48:10,466
{\an1}It also helps reduce
inflammation in blood vessels.

721
00:48:10,500 --> 00:48:13,066
{\an1}So it can actually have
a therapeutic effect

722
00:48:13,100 --> 00:48:16,933
{\an1}on stressed arteries and veins.

723
00:48:16,966 --> 00:48:20,733
{\an1}Even short interactions
can stimulate a rush.

724
00:48:20,766 --> 00:48:23,866
So for the heart,
love looks like thousands

725
00:48:23,900 --> 00:48:27,133
{\an1}of brief encounters
over a lifetime.

726
00:48:28,233 --> 00:48:32,300
{\an1}Which is really well-suited
to a function like a dance.

727
00:48:32,333 --> 00:48:38,533
{\an8}♪♪

728
00:48:38,566 --> 00:48:40,566
{\an1}-I've been working
here 12 years,

729
00:48:40,600 --> 00:48:42,733
{\an1}and there hasn't been
one Thursday

730
00:48:42,766 --> 00:48:48,433
{\an1}that that place hasn't filled up
with at least 150 people.

731
00:48:48,466 --> 00:48:51,300
{\an1}Latins like to dance.

732
00:48:51,333 --> 00:48:54,633
{\an1}-Dance is a good exercise.

733
00:48:54,666 --> 00:48:59,466
{\an1}If you move, it helps a lot,
especially at my age.

734
00:49:24,333 --> 00:49:29,933
{\an1}-I think we know that a lack
of love can be very damaging.

735
00:49:29,966 --> 00:49:34,433
{\an1}The corollary to that is can
the presence of love

736
00:49:34,466 --> 00:49:37,333
{\an1}be beneficial for the heart?

737
00:49:37,366 --> 00:49:40,000
{\an1}We know that people in
longstanding relationships

738
00:49:40,033 --> 00:49:42,333
{\an1}tend to live longer.

739
00:49:42,733 --> 00:49:46,266
{\an1}-♪ Every little movement ♪

740
00:49:46,300 --> 00:49:48,666
{\an1}♪ Every little thing you do

741
00:49:48,700 --> 00:49:52,600
{\an1}-The brain-heart connection
is definitely present

742
00:49:52,633 --> 00:49:55,966
and is something
that we as a field

743
00:49:56,000 --> 00:49:59,433
{\an1}need to investigate more deeply
to really understand its roots.

744
00:49:59,466 --> 00:50:05,133
{\an1}-♪ Said a black magic spell
you put me under ♪

745
00:50:05,166 --> 00:50:08,866
{\an1}-After my husband passed away,
it was hard,

746
00:50:08,900 --> 00:50:11,966
{\an1}but my second family
from the senior center,

747
00:50:12,000 --> 00:50:14,300
{\an1}it gave me so much strength.

748
00:50:14,333 --> 00:50:17,300
It been easier
as time passes by.

749
00:50:18,533 --> 00:50:22,366
{\an1}-♪ Is beyond improvement

750
00:50:22,400 --> 00:50:27,633
{\an1}-Now I'm doing what I love,
and I'll just keep doing it,

751
00:50:27,666 --> 00:50:30,466
whenever I can.

752
00:50:30,500 --> 00:50:36,200
{\an1}-♪ Every little movement

753
00:50:36,233 --> 00:50:37,533
{\an1}[ Cheers and applause ]

754
00:50:37,566 --> 00:50:40,400
{\an1}[ Man speaking Spanish ]

755
00:50:43,300 --> 00:50:47,000
{\an1}-How does the body understand
the passage of time?

756
00:50:48,900 --> 00:50:53,666
{\an1}We as humans have a rhythm
and a cadence to our life

757
00:50:53,700 --> 00:50:57,833
{\an1}that I believe is in many ways,
tied to the heartbeat.

758
00:51:01,766 --> 00:51:05,866
{\an1}-The same pulse inside
every one of us,

759
00:51:05,900 --> 00:51:07,533
{\an1}setting the pace for our lives.

760
00:51:07,566 --> 00:51:15,400
{\an8}♪♪

761
00:51:15,433 --> 00:51:19,433
{\an1}With a tiny thump that we often
forget about that's, in a way,

762
00:51:19,466 --> 00:51:22,100
{\an1}much bigger than we are.

763
00:51:25,533 --> 00:51:28,866
{\an1}All life has a rhythm.

764
00:51:28,900 --> 00:51:32,633
{\an1}You just have to pause
and take a step back to feel it.

765
00:51:36,600 --> 00:51:41,433
{\an1}-The physical world is made up
of pulses of energy.

766
00:51:41,466 --> 00:51:44,333
{\an1}So it's fun to play with that
shift of perspective,

767
00:51:44,366 --> 00:51:47,600
{\an1}to think about our bodies,
more like an ecosystem

768
00:51:47,633 --> 00:51:50,200
{\an1}composed of trillions of cells

769
00:51:50,233 --> 00:51:53,033
{\an1}conspiring every moment
to create our thoughts

770
00:51:53,066 --> 00:51:57,033
{\an1}and keep our heart beating
and keep our breathing going.

771
00:51:57,066 --> 00:51:59,433
{\an8}♪♪

772
00:52:01,200 --> 00:52:06,766
{\an8}♪♪

773
00:52:06,800 --> 00:52:12,966
{\an8}♪♪

774
00:52:13,000 --> 00:52:15,700
{\an8}-To order "Human:
The World Within" on DVD,

775
00:52:15,733 --> 00:52:17,866
{\an8}visit shopPBS.org

776
00:52:17,900 --> 00:52:20,266
{\an7}or call 1-800-PLAY-PBS.

777
00:52:20,300 --> 00:52:29,633
{\an8}♪♪