SEHS: Option A: A2 cont’d Environmental factors part II

Describe how an athlete should acclimatize to heat stress What is acclimatization? It is the process in which an individual organism adjusts to a gradual change in its environment (such as a change in temperature, humidity, photoperiod, or pH), allowing it to maintain performance across a range of environmental conditions. For heat stressors – Perform training sessions in similar environmental conditions (heat and humidity) for 5-10 days results in almost total body adjustments (go slow to start though)

Signs of acclimatization to heat during sub-maximal : Physiological, metabolic and psychological adaptations that occur with heat acclimmatization Lower heart rate Lower core temperature Increased plasma volume Earlier onset of sweating (at a lower temp) More dilute sweat (less electrolyte loss) Reduce rate of muscle glycogen use Decreased psychological effect of effort

Non-shivering thermogenesis (BAT) Outline the principle means by which the body maintains core temperature in cold environments Non-shivering thermogenesis (BAT)

Explain why the body surface area-to-body maintains core temperature in cold environments Larger individuals/athletes have less surface area compared to volume (lower surface area to volume ratios) than smaller individuals/athletes (higher s.a.: vol)

Outline the importance of wind chill in relation to body heat loss Wc = a chill factor created by the increase in the rate of heat loss by convection and conduction caused by wind

Main aspect: thermal conductivity differences between water and air. Explain why swimming in cold water represents a particular challenge to the body’s ability to thermoregulate Main aspect: thermal conductivity differences between water and air.

Discuss the physiological responses to exercise in the cold There are three main adaptive responses by which your body regulates its Tc from chronic exposure to a cold environment: 1. habituation – desesitisation of the normal cold response 2. metabolic acclimatization – greater shivering response = greater heat production 3. Insulative acclimatization – increased vasoconstriction = enhanced heat conservation

HOMEWORK Describe the health risks of exercising in the cold and cold water (frostbite and hypothermia only) Discuss the precautions (specifically clothing type and the measurable unit called a “clo”_ that should be taken when exercising in the cold.