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Unit 21: Applied Sport and Exercise Physiology
Transcript of Unit 21: Applied Sport and Exercise Physiology
P1: Describe the responses of the body to temperature and their effects on exercise and sports performance
Responses to body to
Low body temp results from exposure to the cold
Body's core temp drops
Decrease in breathing rate, blood pressure and heart rate leads to drowsiness and even death
Develops if heat loss exceeds the rate of heat being produced
IMMERSION: severe cold stress due to the body being immersed in water
EXHUASTION: Less severe cold stress due to low temperature including wet and windy weather
URBAN: Mild but prolonged (associated with the elderly and infirm) but rarely seen in sports
Exposure to the cold causes the hypothalamus to react causing involuntary responses. These responses are triggered to raise body core temperature
: involuntary muscle contractions to produce heat in response to the cold environment
Blood vessels in the skin constrict which results in blood being restricted to the deep body organs.
The body core temp reduces gradually where the temp of the skin drops to nearer the external environment.
This restriction of blood flow to the skin is not a problem over short periods, however, over long periods skin cells (deprived of oxygenated blood and nutrients) begin to die (frostbite)
EFFECTS OF LOW TEMPERATURE
Drowsiness is common, followed by a feeling of comfort (despite being cold)
As the body core temp reduces, shivering stops at around 32*c and can lead to death by cardiac arrest at around 24*c
EFFECTS OF LOW TEMPERATURE ON SPORTS PERFORMANCE
The effects of extreme cold can be more harmful than the effects of extreme heat. One such danger is the increased risk of torn muscles and tendons with the greatest risk to sports performance being HYPOTHERMIA.
Exercise in the cold weather forces the body to keep the core body temp at a constant, whilst shunting blood from the extremities to minimise heat loss.
Moderate hypothermia results in muscle fatigue, poor coordination, numbness and disoreintation. Servere hypothermia can result in death, usually by cardiac arrest.
P2: Describe the responses of the body to high altitude and their effects on exercise and sports performance
Is the measurement of elevation above sea level. Performing at altitude has a number of effects, however most of the worlds population live at an altitude close to sea level and these effects are rarely encountered
As altitude increases, atmospheric pressure decreases. This leads to an athlete suffering from hypoxia (inadequate supply of oxygen to the respiratory tissue) as the fall in pressure causes a shortage of oxygen.
RESPONSES OF BODY TO HIGH ALTITUDE
Involves increased ventilation of the lungs caused by an impaired gaseous exchange in the lungs.
In the UK we live within a range (sea level - 500m) where barometric pressure does not effect us enough to cause problems. When we breathe, a normal level of carbon dioxide and an appropriate level of oxygen is measured automatically (by measuring the amount of carbon dioxide level in the blood)
At altitude the air is deficient of oxygen, resulting in low carbon dioxide levels. This causes the blood vessels to contract resulting in reduced blood flow to the brain resulting in dizziness or light-headedness
When an athlete trains in a mountainous range the body responds in a variety of ways, headaches, dizziness, and nausea due to the differences in respiratory adjustments. In time the athelte can adjust to the environment, known as acclimatisation.
*is a resting heart rate higher than normal (more than 100bpm)
Occurs as a consequence of low body temperature
However, other factors can cause Tachycardia including stress, heart disease and drugs
EFFECTS OF HIGH ALTITUDE
Reduction in Partial Pressure of Oxygen
A decrease in pressure in the arteries cause chemoreceptors to become more responsive to an increase in CO2.
This change leads to an increase in ventilation as the brain tries to restore gaseous exchange to a normal level.
As less oxygen is available at high altitude, haemoglobin saturation levels decrease in the blood.
At 5000m above sea level, oxygen saturation is approx. 70% compared to 98% at sea level. Athletes that do not acclimatise will experience a serious decline in performance due to the lack of oxygen.