4. Endocrine glands
Secrete hormones
Blood
Act as chemical signal throughout the body
Control the activity of target tissue or organ
Endocrine response to exercise can improve organ function.
5. Effects of exercises
METABOLIC RATE
Many complex system is interact to regulate
metabolism at during exercise, the major glands
are,
๏ง Anterior pituitary gland
๏ง Thyroid gland
๏ง Adrenal gland
๏ง Pancreas.
6. Anterior pituitary
๏ฑGrowth hormone is a potent anabolic agent (a substance
that build-up organs and tissues, producing growth and cell
differentiation and an increase in size of tissues).
๏ฑIt promotes muscle growth and hypertrophy by facilitating
amino acid transport in to the cells. In addition GH directly
stimulates fat metabolism by the increasing the synthesis of
enzymes involved in that process.
๏ฑGrowth hormone concentrations are elevated during
aerobic exercise in proportion to the exercise intensity and
typically remain elevated for some time after exercise
7. Thyroid gland
๏ฑ Release of thyrotropin from the anterior pituitary
increases during exercise. TSH control the release of
triiodothyronine and thyroxin, so the exercise-induced
increase in TSH would be expected to stimulate the thyroid
gland.
๏ฑExercise increase in plasma thyroxin concentrations, but a
delay occurs between the increase in TSH concentration
during exercise and the increase in plasma thyroxin
concentration.
๏ฑDuring prolonged submaximal exercise, thyroxin
concentrations remain relatively constant after a sharp initial
increase as exercise begins, and triiodothyronine
concentration tend to decrease.
8. Adrenal gland
๏ฑ Release of epinephrine and norepinephrine is affected by a
wide variety of factors, including changes in body position,
psuchlogical stress, and exercise. Plasma concentration of
these hormones increase as individuals gradually increase
their exercise intensity.
๏ฑPlasma norepinephrine concentrations increase markedly at
work rates about above 50% of VO2 max, but epinephrine
concentrations do not increase significantly until the exercise
intensity exceeds 60% to 70% of VO2 max.
9. ๏ฑDuring long duration steady state activity of moderate
intensity, blood concentration of both hormones increase.
When the exercise bout ends, epinephrine return to resting
concentrations within only a few minutes of recovery, but
norepinephrine can remain elevated for several hours.
๏ฑ The glucocorticoids are essential to the ability to adapt to
exercise and other forms of stress. They also help maintain
fairly consistent plasma glucose concentrations even during
long periods without ingestion of food.
10. Pancreas
During exercise lasting 30 min or longer, the body attempts to maintain
plasma glucose concentrations; however, insulin concentrations tend to
decline. The ability of insulin to bind to its receptors on muscle cells
increases during exercise, due in large part to increased blood flow to
muscle. This increases the bodyโs sensitivity to insulin and reduces the
need to maintain high plasma insulin concentrations for transporting
glucose into the muscle cells.
Plasma glucagon, on the other hand, shows gradual increase throughout
exercise.
Exercise, particularly heavy weightlifting, stimulates the release of
luteinizing hormone from your anterior pituitary gland, and luteinzing
hormone triggers testosterone production.
Exercise that involves intense bursts of energy also stimulates the
release of thyroxine from your thyroid gland. Exercise can help you
control or reduce your weight because testosterone and thyroxine speed
up your metabolism.
11. BLOOD SUGAR
๏ฑ Insulin is a hormone that regulates your glucose, or blood
sugar, by transporting it to muscles and tissues that use glucose
for energy.
๏ฑ Excessive insulin in your blood reduces your sensitivity to
insulin and can lead to diabetes. More glucose stays in the blood
when insulin sensitivity goes down, and high blood glucose can
cause nausea, vomiting, shortness of breath, organ failure,
circulation problems and can lead to coma if left untreated.
๏ฑ Exercise might increase your insulin sensitivity by reducing
blood concentrations of insulin. Blood insulin levels begin
decreasing after 10 minutes of aerobic exercise, and weight
training might increase your sensitivity to insulin a rest.
12. BLOOD FLOW
๏ฑThe adrenal medulla releases epinephrine during
exercise and increases epinephrine levels at higher
exercise intensities. Epinephrine increases the amount of
blood that your heart pumps. Epinephrine also enhances
your ability to use muscles during exercise by widening
blood vessels, which lets your muscles get more oxygen-
rich blood.
๏ฑThyroxine secretions during exercise increase the
amount of blood in your body by about 30 percent, and
these secretions might remain elevated for around five
hours.
13. PSYCHOLOGICAL EFFECTS
๏ฑThe effects of exercise on your endocrine system might
positively affect your mental state. Exercise-induced
testosterone might increase confidence and libido.
๏ฑ Conversely, low testosterone levels might inhibit your
motivation, self-confidence, concentration and memory.
Your pituitary gland may produce a large increase in blood
endorphin levels shortly after exercise begins.
๏ฑ Endorphins block your sensitivity to pain, and can
reduce tension or anxiety by inducing a sense of euphoria
