GUNGAHLIN COLLEGE

GUNGAHLIN COLLEGE Human Movement EXERCISE PHYSIOLOGY FACTORS WHICH INFLUENCE SPORTS PERFORMANCE

Exercise in the Heat • Exercise in the Cold • Exercise at Altitiude

Exercise in the Heat • Effects of exercising in the Heat – compared to cool • Increased sweating • Reduced Blood Flow • Increased HR • Increased Q • Increased skin blood flow • Increased anaerobic energy use • Increased muscle glycogen use • Increased core temp

Acclimatisation to Exercise in the Heat • 7 – 10 days of regular exposure to exercise 60-70% of cool climate intensity. Responses • Increased plasma • Earlier sweating response • More copious • More dilute sweat

Impact of Sweat Loss on Performance • Body Weight Loss of 1% • Higher Core Temp • No thirst response (yet) • 0.1 C rise in core temp for each 1% body weight loss

Body Weight Loss of 2-4% • Decrease in V02 max by 10-20% • HR increase doesn’t compensate for decrease in blood volume • 0.4C rise in core temp for each 1% of body weight loss

Prolonged exercise in the heat may result in body weight loss of 6 – 10% • Heat Illnesses, death

Replacing Sweat Loss • In short term exercise, replacing water is a priority. • Water is fine in the short term (cool not iced) • In long term exercise, CHO replaceent may be necessary (sports drinks) • Water is fine in the short term (cool not iced)

Exercise in the Cold • Dangers probably greater thein the heat • Limited means of short term acclimatisation • Physiological Responses to cold a relatively weak • Prevention and survival depend more on behavioural responses

The Environment • Cold in unpleasant • Cold and Windy is Dangerous • Cold, windy and wet is potentially fatal • You can survive a wider range of air temperatures then you can water temperatures • Water is 25 times more capable of removing heat from the body

Physiological Repsonses • Vasoconstriction • Limiting heat loss through radiation. • Intermittent flow through the skin to avid injury • Shivering • Vigorous, fatiguing muscle activity • Increases resting metabolism 4 times • Depletes muscle glycogen • Reduce motor skins

Behavioural Responses • Clothing • Exercise • Shelter • Food • Posture • Respiration

Exercise at Altitude • Areas above 2000m, the amount of O2 in the air is significantly less then sea level • Normal activity is not possible due to serious Oxygen Deficit • Advantages in speed due to decreased air resistance (Mexico City Olympics)

Body Response at Altitude • Brain recognises reduced 02 delivery so more RBC’s are produced. • This increases the bodies ability to transport 02

Acute Responses at Altitude • Increased Breathing Rate • Increased HR • Increased Blood Flow to brain • Headache, nausea • Sleeplessness • Decreased Vo2

Live High, Train Low • Due to the inability to complete extended aerobic training sessions the ‘live high train low’ model sees athletes train at sea level but recover at altitudes of 2000 – 2500 above sea level. • Hypoxic tents or altitude house are used to reduce expenses.

GUNGAHLIN COLLEGE