EFFECT OF ATHLETIC PERFORMANCE ON HORMONAL SYSTEMS

1. EFFECT OF ATHLETIC PERFORMANCE ON HORMONAL SYSTEMS Dr.Sh.Hezarkhani

2. Catecholamines • norepinephrine and epinephrin • Both these hormones progressively increase as workload increases. • Following exercise, resting concentrations are achieved within 30 minutes after exercise.

3. Catecholamines • Mild exercise: produces little or no response • Moderate exercise: levels Norepinephrine significantly increases with minimal change in circulating epinephrine. • Intense or prolonged exercise :both hormones increase significantly

4. Catecholamines • Catecholamines respond rapidly to exercise Acute, short duration maximal exercise as well as intense or prolonged exercise can significantly increase norepinephrine and epinephrine

5. The effects of catecholamine release include: • increased glycogenolysis • increased FFA concentrations • cardiovascular adaptations to exercise • redistribution of circulation to working muscles and to the skin • and mental performance improvement

6. Fluid Homeostasis: • During physical exercise, there is a considerable loss of water and electrolytes in sweat • to maintain body temperature by dissipating heat generated from muscle use.

7. The maintenance of fluid and electrolyte homeostasis depends on the action of: • vasopressin (AVP) • natriuretic peptides • renin-angiotensin-aldosterone (RAA) axis • and catecholamines

8. AVP • AVP concentrations increase during exercise and persist elevated for more than 60 minutes following maximal exercise. • The stimulus for the increase in AVP is : the increase in plasma osmolality and reduction in blood volume

9. ANP and BNP • Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), which may be altered by exercise,also elicit a natriuretic effect. • ANP increase is transitory in exercise of extended duration, with hormone values returning to resting levels over time

10. RAA • The RAA system is closely coupled and responds to exercise. • Increased values of plasma renin activity (PRA) are reported following maximal exercise. • Elevated levels of aldosterone may persist for days after the end of exercise depending on water and sodium intake.

11. PRA, A-II, and aldosterone increment is modulated by: • the sympathetic nervous system • sodium intake • potassium balance • and levels of ACTH.

12. Hypothalamus-Pituitary-Adrenal Axis • Glucocorticoids • Mineralocorticoids • Endorphins

13. Glucocorticoids • exercise of an appropriate intensity is a potent stimulus for cortisol secretion • Physical exercise induces an effect on ACTH and cortisol secretion greater than CRH alone • Increases in plasma lactate is one of the mechanisms responsible for activation of the HPA axis during exercise • A-II and interleukins, are also capable of activating the HPA axis. • Signals of afferent nerves

14. Activation of the HPA axis during aerobic exercise is proportional to the : relative intensity of the exercise and independent of the fitness level of the subject

15. Duration of the physical activity may be important in determining the response of plasma cortisol to exercise

16. The cortisol response is influenced by the type of exercise • intermittent exercise of varying intensities, does not induce activation of the HPA axis • Isometric exercise , induces activation (intensity-dependent) • Anaerobic exercise induces a greater increase in plasma cortisol than aerobic exercise of the same total work output

17. The response of the HPA axis to physical activity is independent of Age and Gender

18. Overtraining syndrome

19. RAA system • PRA, A-II, and aldosterone increase during exercise following : 1) the activity of the sympathetic nervous system 2) sodium intake 3)potassium balance 4) levels of ACTH.

20. β-endorphin • depending on intensity and duration of the physical activity. • β-endorphin increases are also induced by anaerobic exercise and by incremental exercise that reaches anaerobic stages. modulation of pain and the improvement of mood.

21. Detraining syndrome • β-endorphin deficiency • Sudden cessation of regular training • Depressed mood

22. Hypothalamus-Pituitary-Gonadal Axis • Male Gonadal Axis • The effects of physical activity on the male reproductive axis vary with the : 1)intensityand duration of the activity 2)fitnessof the individual 3) his nutritional-metabolic status.

23. Male Gonadal Axis Relatively short, intense exercise usually increases testosterone levels while more prolonged exercise usually decreases serum testosterone levels

24. Male Gonadal Axis • Endurance and other forms of training can induce subclinical inhibition of normal reproductive function • although clinicalexpression of reproductive dysfunction with exercise is uncommon in men

25. Male Gonadal Axis • Increased serum testosterone levels have been reported during: • relatively strenuous free and treadmill running • weight training • and ergometer cycling • The testosterone response has been reported to increase with increased exercise load

26. Male Gonadal Axis • Acute exercise-induced testosterone increments are also seen in older men • the exercise-associated increment in circulating testosterone is not mediated by LH • specific testicular mechanisms are involved

27. Male Gonadal Axis • suppression of serum testosteronelevels occurs during to more prolonged exercise

28. Male Gonadal Axis • decrease of testosterone synthesis, is due to : 1) decreased gonadotropins 2) increased cortisol or catecholamine levels 3)accumulation of metabolic waste materials

29. Male Gonadal Axis • The fall in serum testosterone must result from: decreased production rates decreased binding increased clearance

30. Male Gonadal Axis • Endurance and other forms of training can induce subclinical inhibition of normal reproductive function. • Libidomay also be reduced in some athletes during intense endurance training periods, due to reduced testosterone levels and to chronic fatigue.

31. Male Gonadal Axis • Semen analysis • ↑ β-endorphin • ↓ or ↑ PRL • ↑ cortisol

32. Female Gonadal Axis • can be affected by physical and psychological factors • Many female athletes develop : Delayed menarch oligomenorrhea amenorrhea and luteal phase defects

33. Female Gonadal Axis • Negative energy balance • leptin • which serves as a signal to the CNS with information on the critical amount of adipose tissue stores that is necessary for GnRH secretion and pubertal activation of the hypothalamic-pituitary-gonadal axis

34. Female Gonadal Axis • Possible alternative mechanisms : • the stress-induced activation of the H-P-A axis • endogenous opioid peptides • catecholestrogens • hyperandrogenism.

35. Prolactin • transiently increase with exercise • proportional to the exercise intensity • PRL increments occur when the anaerobic threshold is reached

36. Prolactin • Prolactin correlated with levels of: POMC derivatives ACTH β-endorphins changes in body temperature dehydration is exaggerated by stress is reduced with habituationand hypoxia

37. GH/IGF-I Axis • Physical exercise is an important environmental regulator of the GH/IGF-I axis activity.

38. GH/IGF-I Axis • The GH response to exercise is dependent on the: duration and intensity of the exercise Type of the exercise the fitness level of the exercising subject the refractoriness of pituitary somatotroph cells to the exercise stimuli other environmental factors(NO,lactate)

39. GH/IGF-I Axis • The neuroendocrine pathways that regulate GH secretion during exercise include the : • Cholinergic • Serotoninergic • α-adrenergic • dopaminergic • and opioidergic systems

40. GH/IGF-I Axis ↓ fluid intak→ ↓GH ↑ fat diet → ↓GH ↑ tempreture → ↑ GH Obesity & PCOS → ↓GH GHsecretion is greater in women than in men The acute GH response to aerobic or resistance exercise is reduced with age ↑ GHBP

41. Exercise leads to increases in IGF-I levels(GH-independent mechanisms) • Hemodynamic or metabolic effects of exercise per se might play a role • long periods of exercise training are able to stimulate IGF-I gene expression • ↑IGFBP1

42. Hypothalamus-Pituitary-Thyroid Axis • rT3 increase, particularly when a caloric energy deficiency is associated with exercise. • TSH, T4, fT4, T3, and fT3 levels have been reported to be unaffected, increased, or decreased, varying with the: type and duration of exercise ambient temperature(TSH &FT4↑→↓ ) and energy intake

43. Insulin and Glucose Metabolism • Physical activity affects the metabolism of glucose and other intermediate substrates in normal subjects and in subjects with diabetes mellitus.

44. The effects of exercise on carbohydrate metabolism are complex and involve : 1) type, intensity, and duration of exercise 2) changes in body composition 3) alterations in other behaviors(food intake, degree of insulin deficiency, and a complex time-course of the glucose-insulin response)

45. Maintaning euglycemia during exercise • Activity of α adrenergic system :↓INS • ↑Glucagon ,NE,E