Environmental Factors

Question 1

Define altitude and humidity

Answer 1

Altitude - the height or elevation of an area above sea level
Humidity - the amount of water vapour in the atmospheric air

Question 2

What happens if an athlete competes at high altitude

Answer 2

• breathing frequency increases
• blood volume decreases
• stroke volume decreases
• maximal cardiac output, stroke volume and heart rate decrease with altitude during maximum-intensity exercise

• consider respiratory and cardiovascular effects

Question 3

Define acclimatisation

Answer 3

A process of gradual adaptation to a change in environment (e.g. lower pO2 at altitude)

Question 4

How long should you spend acclimatising for each of these altitudes:
1-2000m
2-3000m
3000+m
5-5500m

Answer 4

1-2000m - 3-5 days
2-3000m - 1-2 weeks
3000m+ - 2+ weeks
5-5500m - 4+ weeks

Question 5

The three most important causes of increased core body temperature in athletes are:

Answer 5

• high and prolonged exercise intensities
• high air temperatures
• high relative humidity

Question 6

Define cardiovascular drift

Answer 6

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

Question 7

The effect of heat, humidity and the body’s thermoregulatory response on the cardiovascular system:

Answer 7

• dilation of arterioles and capillaries to the skin, leading to:
• increased blood flow and
blood pooling in the limbs
• decreased blood volume, venous return, stroke volume, cardiac output and blood pressure, leading to:
• increased heart rate to
compensate
• increased strain on the
cardiovascular system
• reduced oxygen transport to
the working muscles

Question 8

The effect of heat, humidity and the body’s thermoregulatory response on the respiratory system:

Answer 8

• dehydration and drying of the airways in temperatures above 32°C makes breathing difficult, leading to:
• increased mucus production
• constriction of airways
• Decrease volume of air for
gaseous exchange
• increased breathing frequency to maintain oxygen consumption, leading to:
• increased oxygen ‘cost’ of
exercise
• high levels of sunlight increase the effect of pollutants in the air, causing:
• increased irritation of
airways, leading to coughing,
wheezing or asthma
symptoms

Question 9

How to minimise the decrease in performance (due to heat)(pre competition):

Answer 9

• acclimatise to increased temperatures
• use cooling aids such as ice vests to reduce core temperature and delay the effect of high temperature and dehydration

Question 10

How to minimise the decrease in performance (during competition):

Answer 10

• use pacing strategies to alter goals and reduce the feelings of exertion at low-exercise intensities
• wear suitable clothing that maximises heat loss, removing sweat from the skin rapidly, such as lightweight compression wear
• rehydrate as often and as much as possible with a hypotonic or isotonic solution that replaces primarily lost fluids but also glucose and the electrolytes (salts) lost through the sweat

Question 11

How to minimise the decrease in performance (post completion):

Answer 11

• Cooling aids, such as cold towels and cold fans, aid the return of core body temperature gradually
• rehydrate using isotonic solutions that replace lost fluids, glucose and electrolytes