Physiology - Environmental Effects on Body Systems

Define altitude

- The height or elevation of an area above sea level

Define humidity

- The amount of water vapour in the atmospheric air

Outline the short-term effects of altitude on the cardiovascular and respiratory systems

- Decreased ppO2 in the alveoli

- Decreased diffusion gradient to the blood

- Decreased haemoglobin and O2 association in blood

- Decreased O2 transportation to the muscles

- Decreased diffusion gradient to the muscle

- Decreased O2 supply for aerobic energy production

- Increased breathing frequency and HR

- Decreased blood volume and SV

- Decreased VO2 max, aerobic capacity, intensity and duration of exercise

Define acclimatisation

- A process of gradual adaptation to a change in environment

State how long an athlete should acclimatise for when training for an event 2,400m above sea level

- 2 weeks

Outline the benefits of acclimatisation

- Increases RBC production

- Breathing rate and ventilation stabilise

- SV and Q reduce as O2 extraction becomes more efficient

- Reduced chance of altitude sickness, headaches, breathlessness, insomnia and a lack of apetite

Define thermoregulation

- The process of maintaining internal core temperature

Define dehydration

- Loss of water in body tissues, largely caused by sweating

Define hyperthermia

- Significantly raised core body temperature

Outline the 3 main causes of increased core body temperature

- High and prolonged exercise intensities

- High air temperatures

- High relative humidity

Define cardiovascular drift

- Upward drift in heart rate during sustained steady-state activity associated with an increase in body temperature

Outline the effect of heat, humidity and thermoregulation on the cardiovascular system

- Dilation of arterioles and capillaries to the skin

- Increases blood flow and blood pooling to the limbs

- Decreased blood volume, VR, SV, Q and blood pressure

- Increased HR

- Increased strain on the CV system

- Reduced O2 transport to working muscles

Outline the effect of heat, humidity and thermoregulation on the respiratory system

- Dehydration and drying of the airways

- Increased mucus production

- Constriction of the airways

- Decreased volume of air for gaseous exchange

- Increased breathing frequency to maintain O2 consumption

- Increased O2 "cost" of exercise

- High levels of sunlight increase pollutants in the air causing irritation of airways leading to coughing

Describe the effect of temperature and humidity on pre-competition performance

- Acclimatise to increased temperatures for 7-14 days

- Increases plasma volume and the efficiency of Q

- Decreasing the loss of electrolytes to limit fatigue and cramping

- Decreasing HR at a given pace and temperature

- Using cooling aids like ice jackets to reduce core temperature

Describe the effect of temperature and humidity on during competition performance

- Use pacing strategies to alter goals and reduce the feeling of exertion

- Wear suitable clothing to maximise heat loss and remove sweat from the skin rapidly

- Rehydrate often with hypotonic/isotonic drinks to replace glucose and electrolytes

Describe the effect of temperature and humidity on post competition performance

- Cooling aids like cold towels to aid the return of core temp

- Rehydrate using isotonic drinks to replace lost fluids