EFFECT OF ATHLETIC

PERFORMANCE ON HORMONAL

SYSTEMSDr.Sh.Hezarkhani

Catecholamines• norepinephrine and epinephrin• Both these hormones

progressively increase as workload increases.

• Following exercise, resting concentrations are achieved within 30 minutes after exercise.

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

Catecholamines

• Catecholamines respond rapidly to exercise

Acute, short duration maximal exercise

as well as intense or prolonged exercise

can significantly increase norepinephrine and epinephrine

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

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.

The maintenance of fluid and electrolyte homeostasis depends

on the action of:• vasopressin (AVP)• natriuretic peptides• renin-angiotensin-aldosterone

(RAA) axis• and catecholamines

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

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

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.

PRA, A-II, and aldosterone increment is

modulated by:• the sympathetic nervous

system• sodium intake• potassium balance• and levels of ACTH.

Hypothalamus-Pituitary-Adrenal Axis

•Glucocorticoids•Mineralocorticoids•Endorphins

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

• 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

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

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

• The response of the HPA axis to physical activity is independent of

Age and Gender

•Overtraining syndrome

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.

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.

Detraining syndrome

•β-endorphin deficiency • Sudden cessation of regular

training• Depressed mood

Hypothalamus-Pituitary-Gonadal Axis

•Male Gonadal Axis•The effects of physical activity on

the male reproductive axis vary with the :

1)intensity and duration of the activity 2)fitness of the individual

3) his nutritional-metabolic status.

Male Gonadal Axis

Relatively short, intense exercise usually increases testosterone levels

while

more prolonged exercise usually decreases

serum testosterone levels

Male Gonadal Axis

• Endurance and other forms of training can induce subclinical inhibition of normal reproductive function

• although clinical expression of reproductive dysfunction with

exercise is uncommon in men

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

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

Male Gonadal Axis

•suppression of serum testosterone levels occurs

during to more prolonged exercise

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

Male Gonadal Axis

• The fall in serum testosterone must result from:

decreased production rates decreased binding increased clearance

Male Gonadal Axis

• Endurance and other forms of training can induce subclinical inhibition of normal reproductive function.

•Libido may also be reduced in some athletes during intense endurance training periods, due to reduced testosterone levels and to chronic fatigue.

Male Gonadal Axis

• Semen analysis• ↑ β-endorphin• ↓ or ↑ PRL• ↑ cortisol

Female Gonadal Axis

• can be affected by physical and psychological

factors• Many female athletes develop : Delayed menarch oligomenorrhea amenorrhea and luteal phase defects

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

Female Gonadal Axis

• Possible alternative mechanisms :

• the stress-induced activation of the H-P-A axis

• endogenous opioid peptides• catecholestrogens• hyperandrogenism.

Prolactin• transiently increase with exercise

• proportional to the exercise intensity

• PRL increments occur when the anaerobic threshold is reached

Prolactin• Prolactin correlated with levels of: POMC derivatives ACTH β-endorphins

changes in body temperature dehydration is exaggerated by stress is reduced with habituation

and

hypoxia

GH/IGF-I Axis

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

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)

GH/IGF-I Axis• The neuroendocrine pathways

that regulate GH secretion during exercise include the :

• Cholinergic• Serotoninergic• α-adrenergic• dopaminergic

• and opioidergic systems

GH/IGF-I Axis

↓ fluid intak→ ↓GH ↑ fat diet → ↓GH ↑ tempreture → ↑ GH Obesity & PCOS → ↓GH

GH secretion is greater in women than in men

The acute GH response to aerobic or resistance exercise is reduced with age

↑ GHBP

• 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

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

Insulin and Glucose Metabolism

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

• 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)

Maintaning euglycemia during exercise

• Activity of α adrenergic system :↓INS

• ↑Glucagon ,NE,E