There
are many physical, mental, and physiological benefits
to regular exercise. One category of benefits is the
impact that exercise has on many of your body's hormones.
Hormones are chemical messengers within your body
that affect almost all aspects of human function:
1.
Growth Hormone
- Stimulates
protein synthesis (muscle tone/development), and strength
of bones, tendons, ligaments, and cartilage.
- Decreases
use of glucose and increases use of fat as a fuel
during exercise. This helps to reduce body fat and
to keep blood glucose at a normal level which helps
you to exercise for a longer period of time.
Release
of growth hormone from the pituitary gland in the
brain is increased with increasing aerobic exercise
time, especially more intense exercise such as interval
training.
2.
Endorphins
- An
endogenous opioid from the pituitary gland that blocks
pain, decreases appetite, creates a feeling of euphoria
(the exercise high), and reduces tension and anxiety.
Blood
levels of endorphins increase up to five times resting
levels during longer duration (greater than 30 minutes)
aerobic exercise at moderate to intense levels and
also during interval training.
Also,
after several months of regular exercise, you develop
an increased sensitivity to endorphins (a higher high
from the same level of endorphins), and endorphins
that are produced tend to stay in your blood for a
longer period of time. This makes longer duration
exercise easier (you're feeling no pain) and it causes
your exercise high to last for a longer period of
time after exercise.
3.
Testosterone
- An
important hormone in both males and females for maintaining
muscle tone/volume/strength, increasing basal metabolic
rate (metabolism), decreasing body fat, and feeling
self-confident. It's produced by the ovaries in females
and by the testes in males.
- Females
have only about one tenth the amount of testosterone
that males do, but even at that level in females it
also plays a role in libido and intensity of orgasms.
Production of testosterone in females begins to decline
as a woman begins to approach menopause (usually late
thirties) and in males it begins to decline in his
forties.
Blood
levels of testosterone increase with exercise in both
males and females beginning about 20 minutes into
an exercise session, and blood levels may remain elevated
for one to three hours after exercise.
4.
Estrogen
- The
most biologically active estrogen, 17 beta estradiol,
increases fat breakdown from body fat stores so that
it can be used and fuel, increases basal metabolic
rate (metabolism), elevates your mood, and increases
libido.
This
hormone is at much higher blood levels in females,
but the ovaries begin to produce less of it as a woman
begins to approach menopause. The amount of 17 beta
estradiol secreted by the ovaries increases with exercise,
and blood levels may remain elevated for one to four
hours after exercise.
5.
Thyroxine (T4)
- A
hormone produced by the thyroid gland, Thyroxine raises
the metabolic rate ("metabolism") of almost
all cells in the body. This increase in "metabolism"
helps you to feel more energetic and also causes you
to expend more calories, and thus is important in
weight loss.
Blood
levels of thyroxine increase by about 30% during exercise
and remain elevated for several hours afterward -
this period of time is increased by an increase in
intensity and/or duration of exercise. Regular exercise
also increase thyroxine levels at rest.
6.
Epinephrine
- A
hormone produced primarily by the adrenal medulla
that increases the amount of blood the heart pumps
and directs blood flow to where it's needed.
- Stimulates
breakdown of glycogen (stored carbohydrate) in the
active muscles and liver to use as fuel. It also stimulates
the breakdown of fat (in stored fat and in active
muscles) to use as fuel. The amount of epinephrine
released from the adrenal medulla is proportional
to the intensity and duration of exercise.
7.
Insulin
An
important hormone in regulating (decreasing) blood
levels of glucose ("blood sugar") and in
directing glucose, fatty acids, and amino acids into
the cells. Insulin secretion by the pancreas is increased
in response to a rise in blood sugar as is often the
case after a meal.
Typically,
the larger the meal, or the greater the quantity of
simple sugars consumed, the larger the insulin response.
This is another reason that it's good to eat small
frequent meals and to limit consumption of sugar and
of processed bread, pasta and rice. The whole grain
(non- processed) versions of bread, pasta and rice,
etc. are much healthier choices.
Blood
levels of insulin begin to decrease about 10 minutes
into an aerobic exercise session and continue to decrease
through about 70 minutes of exercise. Regular exercise
also increases a cell's sensitivity to insulin at
rest, so that less insulin is needed.
8.
Glucagon
A hormone
that is also secreted by the pancreas, but it's job
is to raise blood levels of glucose ("blood sugar").
When blood sugar levels get too low, glucagon is secreted
and causes stored carbohydrate (glycogen) in the liver
to be released into the blood stream to raise blood
sugar to a normal level. It also causes the breakdown
of fat so that it can be used as fuel.
Glucagon
typically begins to be secreted beyond 30 minutes
of exercise when blood glucose levels may begin to
decrease.
So,
next time you're exercising, think about all the wonderful
things that are happening to your hormones. It might
even make you want to do more exercise!
