Hormones and Exercise

Endocrine System

•      3 Components:

–   Host organ

–   Hormones

–   Target (receptor) cells or organs

Types of Glands

•      Endocrine gland – secrete hormones that diffuse into the bloodstream.


•      Exocrine gland – have secretory ducts that lead directly to specific compartment or surface that requires the hormone; e.g. sweat glands and glands of upper digestive tract.

Hormones & Function

•      Hormones – chemical substances that carry messages to regulate growth, metabolism, and reproduction.  Hormones also enhance body’s ability to respond to physical and psychological stress.

Anterior Pituitary Hormones
and Exercise

•      Growth Hormone – stimulates tissue growth, mobilizes fat for energy, and inhibits CHO metabolism; with exercise


•      Prolactin – inhibits testosterone, and mobilizes fat for energy; with exercise


•      Endorphins – block pain and promote euphoria;

      with long-duration exercise

Posterior Pituitary Hormones
and Exercise


•      Vasopressin (ADH) – controls water excretion by kidneys; with exercise

Adrenal Cortex Hormones
and Exercise

•      Cortisol – promotes fat and protein catabolism, conserves blood sugar; with intense exercise


•      Aldosterone – promotes sodium, potassium, and water retention by the kidneys; with exercise

Adrenal Medulla Hormones
and Exercise

•      Epinephrine (adrenaline) – facilitates sympathetic activity, increases heart activity, regulates blood vessels, increases glycogen catabolism and fat release; with intense exercise


•      Norepinephrine – similar functions as epinephrine; with exercise

Thyroid Hormones
and Exercise


•      Thyroxine (T4) & Triiodothyronine (T3) – stimulate metabolism and regulate cell growth and activity; with exercise

Pancreatic Hormones
and Exercise

•      Insulin – promotes glucose transport into cells and promotes fatty acid and amino acid transport into cells; with exercise


•      Glucagon – promotes release of glucose from liver to blood, increases fat metabolism, and reduces amino acid levels; with exercise

Parathyroid Hormone
and Exercise


•      Parathyroid hormone – raises blood calcium and lowers blood phosphate; with long-term exercise

Ovary Hormones
and Exercise

•      Estrogen and Progesterone – control menstrual cycle, increase fat deposition, and promote female gender characteristics;

   with exercise depending on phase of menstrual cycle.

Testicular Hormones
and Exercise

•      Testosterone – controls muscle size, increases red blood cells, decreases body fat, and promotes male gender characteristics; with exercise

Hormonal Problems

•      Aldosterone

–   Increased production of this hormone is associated with high blood pressure; often times in obese teenagers

•   Associated with:

–   salt sensitivity (increased body water)
–   sodium intake
–   sensitivity to insulin’s effects

Hormonal Problems

•      Diabetes Mellitus

•   Type I diabetes – lack of or no secretion of insulin from pancreas

–   dependence on exogenous insulin

•   Type II diabetes – cells resist insulin’s effects

–   May need exogenous insulin or must exercise to improve body’s ability of glucose uptake

Diabetes and Exercise

•      Type I Diabetes

–   Problems:

•   Hypoglycemia can result with exercise if insulin has been taken recently


•   Hyperglycemia can result with exercise if no insulin taken for long period of time

Exercise Guidelines for
Type I Diabetes

•      Monitor blood glucose before, during, and after exercise

•      Ingest 15-30 grams of CHO for each 30 min of intense exercise

•      Consume CHO snack after exercise

•      Decrease insulin dose

•      Avoid exercising the muscles where insulin injection was given for 1 hour

•      Avoid exercising in late evening

Exercise Guidelines for
Type II Diabetes

•      Similar to Type I


Exercise Benefits for
Individuals with Diabetes

•      Improved glycemic control (increased sensitivity of tissues to insulin so better uptake of glucose)

•      Decreases cardiovascular risk factors

•      Promotes weight loss

•      Decreases anxiety levels

When Exercise Should be Avoided in Diabetics

•      Retinal hemorrhage or recent eye surgery

•      Fever or infection is present

•      Blood glucose < 80 mg/dl

–   Eat extra CHO until glucose is above 120 mg/dl before exercising

•      Blood glucose > 250 mg/dl and urine ketones are present

–   Decrease blood glucose with insulin injection

Hormonal Response to
Exercise Training


•      After training, exercise at same absolute intensity will result in a lower hormonal response in most cases


Specific hormone responses to Training

•      Human growth hormone - ↓ response with exercise; higher resting values

•      Prolactin - ↓ resting values

•      Testosterone - ↓ resting values in women but possible ↑ in men with resistance training

•      Vasopressin (ADH) - ↓ response with exercise


Specific hormone responses to Training

•      Cortisol - slight ↑ with exercise in trained

•      Epinephrine & Norepinephrine -  ↓ response with exercise

•      Insulin - ↓ response with exercise due to increase in sensitivity

•      Glucagon - ↓ response with exercise




Immune System
and Exercise