34
HUMAN ANATOMY
The heart, an intricate network of
vessels, and the blood circulating
through them make up your
cardiovascular system.
SYSTEM OVERVIEW
Your heart constantly beats to pump blood
around your body, removing waste and
delivering vital oxygen. Research on yoga
suggests profound benefits for cardiovascular
health, including a reduced risk of heart
disease. Yoga has been shown to clinically
improve blood pressure, cholesterol levels,
and cardiovascular resilience (see opposite).
CARDIOVASCULAR
SYSTEM
Composition of blood
Adults have about 11 pints (5 liters) of blood
circulating around the body. Blood is a connective
tissue composed of red blood cells, white blood
cells, and platelets suspended in a liquid called
plasma. It provides oxygen, nutrients, and hormones,
as well as removing waste from cells.
Platelets
Also called
thrombocytes,
they help
blood to clot
Red blood cells
Also called erythrocytes,
they deliver oxygen
White blood cells
Also called leukocytes,
they fight invaders
Jugular vein
Returns blood from
brain to heart
Femoral vein
Delivers blood from
lower limbs to heart
Femoral artery
Carries blood
to thighs
Popliteal artery
Carries blood to
knee and calf
Great saphenous vein
Longest vein in the body
Subclavian artery
Carries blood to
arm and hand
Carotid
artery
Delivers
blood to
brain
Superior vena cava
Returns blood
back to heart
Aorta
Largest artery in
your body
Heart
Muscular pump
for blood
Inferior vena cava
Returns blood from
lower body to heart
Abdominal aorta
Delivers blood to
abdomen and lower body
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35
Heart rate variability
Heart rate variability (HRV) is the heart’s
ability to adapt fast. It is better for your
pulse to vary rather than tick steadily.
High HRV shows autonomic resilience
and may lead to improved physical,
emotional, and cognitive
function. Yoga appears
to improve HRV.
Hypertension
Research shows that yoga can reduce
blood pressure signicantly. With
more than 1 billion people living with
hypertension, yoga oers a cost-eective
adjunct to care with minimal to no side
eects. Consult your
doctor about any blood
pressure shifts.
Cholesterol
Reports have shown that yoga can
increase “good” cholesterol (high-density
lipoprotein or HDL) and decrease “bad”
cholesterol (low-density lipoprotein or
LDL). This reduces the
risk of heart disease
by preventing
arterial narrowing.
Heart disease
A meta-analysis suggests that yoga reduces
heart disease risk as well as
or better than
accepted exercise guidelines.
Long-term
clinical trials have shown that
a yogic lifestyle— with
asanas, meditation, social
support, and a plant-
based diet—could
reverse heart disease.
HEART AND CIRCULATION
Circulation has two loops: pulmonary (lungs) and systemic
(body). Veins carry blood to the heart, and arteries carry it
away. Veins are shown in blue to represent deoxygenation, and
arteries are red for oxygenation. The exceptions are pulmonary
arteries (deoxygenated) and pulmonary veins (oxygenated).
Cerebral arteries
Deliver oxygenated
blood to brain
Pulmonary vein
Returns oxygenated
blood from lungs
Capillaries
Where exchange
occurs
Artery wall
Thick muscular
walls adjust
pressure
Cerebral veins
Return deoxygenated
blood from brain
Pulmonary artery
Delivers deoxygenated
blood to lungs
Vein valve
One-way valves
prevent backflow
Vein
Veins return blood to your
heart from cells. The blood is
usually deoxygenated
(oxygen-poor).
Artery
Arteries carry blood away
from your heart to cells. The
blood is usually oxygenated
(oxygen-rich).
NARROWED
ARTERY
DAMAGED
HEART TISSUE
BLOOD
PRESSURE
MONITOR
HEARTBEAT
Carotid
artery
Delivers
blood to
brain
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