4-Endocrine Response to Exercise; Diabetes Mellitus and Fitness

Advanced Nutrition and Fitness

Dr. Siham Gritly

Dr. Siham Gritly

objectives

• At the end of the lecture student should be able to understand;

• The major glands of the endocrine system• Hormones that important in physical exercise• Diabetes Mellitus and exercise

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The major endocrine glands: 1 Pineal gland 2 Pituitary gland 3 Thyroid gland 4 Thymus 5 Adrenal gland 6 Pancreas 7 Ovary (female) 8 Testes (male)

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Endocrine system

• the endocrine system is a system of glands, (ductless) each of which secretes a type of hormone.

• hormone is directly released into the bloodstream to regulate the body functions.

• It derives from the Greek words "endo" meaning inside, within, and "crinis" for secrete.

• field of study dealing with the endocrine system endocrinology

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• Hormones regulate various human functions, including;

• metabolism,

• growth and development,

• body tissues (the physical and chemical processes of the body),

• sexual development and function.

 

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• Most hormones are secreted from the glands that produce them under the influence of stimulating hormones from the hypothalamus.

• The hypothalamus is a part of the brain involved in the control of involuntary activity in the body; contains many centers of neural control such as temperature, hunger, appetite and thirst

• These hormones in turn are activated by releasing hormones from the pituitary gland.

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Exercise;

• Look for the major endocrine glands

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The major glands of the endocrine system

• are;• the hypothalamus, (link the nervous system to

the endocrine system via the pituitary gland (hypophysis)

• pituitary, (secretes nine hormones that regulate homeostasis)

• thyroid, • parathyroids,

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• adrenals, • pineal gland, (melatonin that helps to regulate

sleep/wake)• the reproductive organs (ovaries and testes). • The pancreas; insulin and glucagon

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• Hormones can be classified ;–Steroid hormones are lipid, they are formed

from cholesterol.

–Non-steroid hormones are proteins, peptides, or amino acids.

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Reference; MedicineNet.Inc

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Endocrine Response to Exercise

• Many hormones play a role in physical exercise; the endocrine response to exercise can improve organ function, physical fitness and overall psychological state.

• without hormones, exercise would be limited. • Vigorous exercise, in particular, might

improve endocrine function.

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Hormones important in physical exercise

• Hormones important in physical exercise include;

1-testosterone from the testes,

2-norepinephrine or adrenalin and cortisol from the adrenal glands,

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3- thyroxin from the thyroid gland

4- human growth hormone -- also called HGH or somatotropin -- from the pituitary gland.

5-insulin and glucagon from the pancreas,

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Male Reproductive system1-Testosterone from the Testes

• Testosterone sex hormone contributes to muscle mass and strength,

• serum testosterone, increase is correlated with the duration, intensity and type of exercise.

• Overexertion, however, was found to have the

opposite effect on testosterone levels.

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The Adrenal Gland adapted from ScheerMed

2-adrenalin and cortisol from the adrenal glands,

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norepinephrine and cortisol from the adrenal glands,

• The adrenal glands involved in maintaining;

*blood sugar levels,

*moderating the immune system response,

*providing the precursors for the production of sex hormones

*responding to stressful situations through the release of adrenaline and cortisol.

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Adrenal Gland Hormones & Exercise Effects

• The adrenal glands produce numerous hormones include adrenalin, cortisol, epinephrine;

• * adrenalin or norepinephrine, is released in greater amounts during exercise, providing body system with increased energy in the form of glucose and free fatty acids

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• *cortisol, facilitates the breakdown and release of amino acids from muscle tissue to provide substrate to liver for gluconeogenesis

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• Epinephrine, (The adrenal medulla) during exercise intensities epinephrine increase at higher level

• Epinephrine stimulate the liver to release glucose and accelerates the use of glycogen in the muscle

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The Thyroid gland Adapted medicineNet.inc

3- thyroxin from the thyroid gland

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• Thyroid gland secrete hormone thyroxin• Function during exercise• Thyroxin secretions during exercise lead to;-

*increase the amount of blood in the body by about 30 percent,

• *increase the metabolism within the human body

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The Pituitary gland4- human growth hormone from pituitary gland

Adapted medicineNet.inc

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• Exercise, particularly heavy weightlifting (strength exercise), stimulates the release of luteinizing hormone from the anterior pituitary gland,

• luteinizing hormone activate testosterone production.

• Intense Exercise stimulates the release of thyroxine from the thyroid gland.

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The pancreasadapted from MedicineNet.Inc

5-insulin and glucagon from the pancreas,

Adapted medicineNet.inc

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The pancreas

The pancreas has 2 functions;

1-digestive function; the exocrine pancreas, secretes digestive enzymes

2-hormonal functions; the endocrine pancreas, secretes hormones called insulin and glucagon.

• These hormones regulate the level of glucose in the blood.

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• Insulin and glucagon are both synthesized in the pancreas,

• These hormones have competing functions; • -insulin stimulates glucose uptake by body

tissues, • - glucagon increase the rate of

gluconeogenesis in the liver and help to increase blood glucose levels

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• During exercise, Glucagon levels rise and insulin levels fall so as to increase glucose release into the bloodstream.

• When exercise end, insulin rises and glucagon drops so that ingested foods are rapidly used to replenish glycogen,

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• Endocrine response to exercise; Diabetes Mellitus and fitness

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Diabetes Mellitus

• Diabetes Mellitus; a disorder of carbohydrate metabolism due to disturbances in production or utilization of insulin, results in high blood glucose levels and loss of sugar in urine

• .

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• diabetes mellitus are of two types either;

• 1- Type 1 DM; people cannot produce insulin.

it results from the body's failure to produce insulin, and presently requires the person to inject insulin.

• 2- Type 2 DM; the insulin they produce is ineffective in stimulating the uptake of blood sugar (glucose) into the body's cells.

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• If diabetes is untreated, blood sugar rises to high levels that can eventually cause blindness, nerve damage, and other complications.

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• Both Type 1 and 2 DM are diagnosed by detection of a fasting (>8 h) plasma glucose level that exceeds 126 mg/dl

• If a plasma glucose concentration greater than

200 mg/dl at 2 h after an oral glucose of 75 g of glucose individual known to be diabetic

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Response of hypothalamus to blood glucose level

• If the sugar levels in the blood fall far below their usual range, the brain (hypothalamus) responds by stimulating;

• *the adrenal glands to release, 1-adrenaline or norepinephrine, 2-epinephrine and 3-cortisol,

• 1-adrenalin or norepinephrine, is released in greater amounts during exercise increased energy in the form of glucose and free fatty acids

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• 2-Epinephrine stimulate the liver to release glucose and accelerates the use of glycogen in the muscle

• 3-cortisol, release of amino acids from muscle tissue to provide substrate to liver for gluconeogenesis

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• *-the pancreas to release glucagon and insulin, Insulin is a hormone produced in the pancreases which enables body cells to absorb glucose, for energy production, glucagon increase the rate of gluconeogenesis in the liver and help to increase blood glucose levels

• *- the pituitary gland to release growth hormone, all of which cause the liver to regulate glucose into the blood.

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Hypoglycemia.

• Normal blood glucose level in the blood usually range from 80-100 mg of glucose/ 100ml of blood

• Below this range athletes could enter into hypoglycemic condition

• Hypoglycemia is characterized by low blood sugar level (glucose)

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• Hypoglycemia lead to impairment of central nervous system

• Sweating, beating heart, shaking, hunger, confusion, drowsiness, difficulty with speech, nausea, and headache are the main symptoms .

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Diabetes Mellitus and exercise Metabolic Responses to Exercise

• Regular exercise is highly recommended for many people who have either Type 1 or Type 2 Diabetes Mellitus (DM).

• During exercise, skeletal muscle is the most important tissue in the body for glucose uptake.

the contracting muscles produce their own insulin-like effect, causing the rapid uptake of glucose from the blood.

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Other hormones such as epinephrine (adrenaline), glucagon and cortisol assess to maintain and increase blood glucose levels during exercise

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• Avoiding hypoglycemia or hyperglycemia can also be achieved by increasing or decreasing, respectively, the amount of carbohydrate ingested before planned exercise.

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Functions of Insulin during and after exercise

1- Stimulation of glucose uptake into most cells of the body,

2- Inhibition of glucose release from the liver,

3- Inhibition of the release of fatty acids from storage tissue,

4-Facilitation of protein synthesis in the body's cells,

5- Stimulation of the re-synthesis of muscle glycogen after exercise

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REFERENCES

• American Diabetes Association (2002). Clinical Practice Recommendations:2002. Diabetes Care 25 (suppl. 1):S64-S68.

• Sareen Gropper, Jack Smith and James Groff, Advanced Nutrition and Human Metabolism, fifth ed. WADSWORTH

• Melvin H Williams 2010; Nutrition for Health, Fitness and Sport. 9th ed, McGraw Hill

• Heymsfield, SB.; Baumgartner N.; Richard and Sheau-Fang P. 1999.

Modern Nutrition in Health and Disease; Shils E Maurice, Olson A. James, Shike Moshe and Ross A. Catharine eds. 9th edition

• Guyton, C. Arthur. 1985. Textbook of Medical Physiology. 6th edition, W.B. Company

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• Christopher D. Jensen, PhD, MPH, RD ;Nutrition & Epidemiology Researcher Part 1: Sports Nutrition for Athletes with Type 1 Diabetes: Interplay of Diet, Insulin Therapy, and Exercise

• American Diabetes Association (2002). Clinical Practice Recommendations:2002. Diabetes Care 25 (suppl. 1):S64-S68.

• By Kevin Beck2011. Endocrine Response to Exercise

• medicineNet.inc

• Hayashi et al., 1997; Holloszy, 2003; Nesher et al., 1985; Ploug et al., 1984

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• http://www.livestrong.com/article/405612-effects-of-exercise-on-endocrine-system/#ixzz1gILKH9MT

• Virtual Medical Centre: Endocrine System "Adaptive Medicine"; Exercise and Testosterone; Te-Chi Liu, et al.; August 31, 2009

• "Journal of Applied Physiology"; Hypothalamic-Pituitary-Adrenal Responses to Short

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References;