1
99:59:59,999 --> 99:59:59,999
At some point between the first and fifth 
century CE,

2
99:59:59,999 --> 99:59:59,999
the Hindu sage Patañjali began to codify
the ancient,

3
99:59:59,999 --> 99:59:59,999
meditative traditions practiced 
throughout India.

4
99:59:59,999 --> 99:59:59,999
He recorded techniques nearly as old as
Indian civilization itself

5
99:59:59,999 --> 99:59:59,999
in 196 manuals called the Yoga Sutras.

6
99:59:59,999 --> 99:59:59,999
These texts defined yoga as the ‘yoking’ 
or restraining of the mind

7
99:59:59,999 --> 99:59:59,999
from focusing on external objects in 
efforts

8
99:59:59,999 --> 99:59:59,999
to reach a state of pure consciousness.

9
99:59:59,999 --> 99:59:59,999
Over time, yoga came to incorporate
physical elements

10
99:59:59,999 --> 99:59:59,999
from gymnastics and wrestling.

11
99:59:59,999 --> 99:59:59,999
Today, there are a multitude of approaches
to modern yoga –

12
99:59:59,999 --> 99:59:59,999
though most still maintain the three core
elements of Patañjali’s practice:

13
99:59:59,999 --> 99:59:59,999
physical postures, breathing exercises, 
and spiritual contemplation.

14
99:59:59,999 --> 99:59:59,999
Yoga’s supporters say this blend 
of physical and mental exercise

15
99:59:59,999 --> 99:59:59,999
has a unique set of advantages 
for our health.

16
99:59:59,999 --> 99:59:59,999
Yoga is widely believed to improve 
strength and flexibility,

17
99:59:59,999 --> 99:59:59,999
boost heart and lung function, and enhance
psychological well-being.

18
99:59:59,999 --> 99:59:59,999
But what does the science actually say 
about the modern benefits

19
99:59:59,999 --> 99:59:59,999
of this ancient tradition?

20
99:59:59,999 --> 99:59:59,999
Despite attempts by many researchers, 
yoga has proven a tough subject to study.

21
99:59:59,999 --> 99:59:59,999
Its unique combination of activities makes
it difficult to determine

22
99:59:59,999 --> 99:59:59,999
which component is producing a 
specific health benefit.

23
99:59:59,999 --> 99:59:59,999
Additionally, yoga studies are often made 
up of small sample sizes

24
99:59:59,999 --> 99:59:59,999
that lack diversity,

25
99:59:59,999 --> 99:59:59,999
and the heavy reliance on self-reporting
makes results subjective.

26
99:59:59,999 --> 99:59:59,999
However, there are some health benefits

27
99:59:59,999 --> 99:59:59,999
that have more robust scientific 
support than others.

28
99:59:59,999 --> 99:59:59,999
Let’s start with flexibility and strength.

29
99:59:59,999 --> 99:59:59,999
Contorting your body into yoga’s physical
postures stretches multiple muscle groups.

30
99:59:59,999 --> 99:59:59,999
In the short term, stretching can change
the water content of these muscles,

31
99:59:59,999 --> 99:59:59,999
ligaments, and tendons to make 
them more elastic.

32
99:59:59,999 --> 99:59:59,999
Over time, regular stretching 
stimulates stem cells

33
99:59:59,999 --> 99:59:59,999
that then differentiate into more 
elastic collagen and muscle tissue.

34
99:59:59,999 --> 99:59:59,999
Frequent stretching also reduces the
body’s natural reflex

35
99:59:59,999 --> 99:59:59,999
to constrict muscles,

36
99:59:59,999 --> 99:59:59,999
improving your pain tolerance for feats
of flexibility.

37
99:59:59,999 --> 99:59:59,999
Researchers haven’t found that any one 
form of yoga

38
99:59:59,999 --> 99:59:59,999
improves flexibility more than another,

39
99:59:59,999 --> 99:59:59,999
so the impact of specific 
postures is unclear.

40
99:59:59,999 --> 99:59:59,999
Additionally, yoga hasn’t proved superior 
to other low-impact exercise

41
99:59:59,999 --> 99:59:59,999
when it comes to improving fitness 
and flexibility in healthy populations.

42
99:59:59,999 --> 99:59:59,999
However, the practice has been shown to be
an especially powerful therapeutic tool.

43
99:59:59,999 --> 99:59:59,999
In studies involving patients with a 
variety of musculo-skeletal disorders,

44
99:59:59,999 --> 99:59:59,999
yoga was more helpful at reducing pain and
improving mobility

45
99:59:59,999 --> 99:59:59,999
than other forms of low-impact exercise.

46
99:59:59,999 --> 99:59:59,999
Adding yoga to an existing exercise 
routine can improve strength

47
99:59:59,999 --> 99:59:59,999
and flexibility for hard to treat 
conditions like chronic lower back pain,

48
99:59:59,999 --> 99:59:59,999
rheumatoid arthritis, and osteoporosis.

49
99:59:59,999 --> 99:59:59,999
Yoga’s mix of physical exercise and 
regimented breathing

50
99:59:59,999 --> 99:59:59,999
has proven similarly therapeutic 
for lung health.

51
99:59:59,999 --> 99:59:59,999
Lung diseases like chronic bronchitis, 
emphysema, and asthma

52
99:59:59,999 --> 99:59:59,999
shrink the passageways that carry oxygen,

53
99:59:59,999 --> 99:59:59,999
while weakening the membrane that 
brings oxygen into the blood.

54
99:59:59,999 --> 99:59:59,999
But breathing exercises like those found
in yoga

55
99:59:59,999 --> 99:59:59,999
relax the muscles constricting those
passageways and improve oxygen diffusion.

56
99:59:59,999 --> 99:59:59,999
Increasing the blood’s oxygen content
is especially helpful

57
99:59:59,999 --> 99:59:59,999
for those with weak heart muscles

58
99:59:59,999 --> 99:59:59,999
who have difficulty pumping
enough oxygen throughout the body.

59
99:59:59,999 --> 99:59:59,999
And for those with healthy hearts,

60
99:59:59,999 --> 99:59:59,999
this practice can lower blood pressure
and reduce risk factors

61
99:59:59,999 --> 99:59:59,999
for cardiovascular disease.

62
99:59:59,999 --> 99:59:59,999
Yoga’s most widely celebrated benefit
may be the most difficult to prove:

63
99:59:59,999 --> 99:59:59,999
its psychological effects.

64
99:59:59,999 --> 99:59:59,999
Despite the longstanding association 
between yoga and psychological wellbeing,

65
99:59:59,999 --> 99:59:59,999
there’s little conclusive evidence on 
how the practice affects mental health.

66
99:59:59,999 --> 99:59:59,999
One of the biggest claims

67
99:59:59,999 --> 99:59:59,999
is that yoga improves symptoms of 
depression and anxiety disorders.

68
99:59:59,999 --> 99:59:59,999
However, since diagnosis of these 
conditions

69
99:59:59,999 --> 99:59:59,999
varies widely in origin and severity,

70
99:59:59,999 --> 99:59:59,999
it’s difficult to quantify yoga’s impact.

71
99:59:59,999 --> 99:59:59,999
There is evidence to suggest yoga can 
help reduce the symptoms of stress,

72
99:59:59,999 --> 99:59:59,999
but no more than meditation
or relaxation.

73
99:59:59,999 --> 99:59:59,999
Research on the effects of 
yoga is still evolving.

74
99:59:59,999 --> 99:59:59,999
In the future, we’ll need larger studies, 
incorporating diverse participants,

75
99:59:59,999 --> 99:59:59,999
which can measure yoga’s impact
on heart attacks, cancer rates,

76
99:59:59,999 --> 99:59:59,999
cognitive function and more.

77
99:59:59,999 --> 99:59:59,999
But for now, we should primarily practice
yoga as a way to exercise,

78
99:59:59,999 --> 99:59:59,999
reflect, and relax.

79
99:59:59,999 --> 99:59:59,999
So if you miss your class, don’t tie 
yourself into knots about it.