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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. To receive an article on interval

training, send email to: Intervals@Landry.com

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 org*sms. Production of testosterone in females begins

to decline as a woman begins to approach menopause

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

riases 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 those products are a

much healthier choice.

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 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!

copyright 2004 by Greg Landry, M.S

Author and exercise physiologist, Greg Landry,

offers free weight loss and fitness success stories

and targeted, highly affective weight loss programs

for women, men, type 2 diabetics, and people with

slow metabolisms and hypothyroidism..

http://www.Landry.com