Environmentally friendly - perhaps not to athletes
Brian Mackenzie explains how altitude, temperature and time can affect athletic performance.
As an athlete passes through an athletic career, numerous things happen which bring changes in his/her environment. In the early stages, the most common changes involve long, tiring journeys, sometimes combined with a stay for a number of days in an unfamiliar place. Later in the athlete's career, there are more serious changes to take note of and to prepare for. There are three environmental conditions which an athlete will have to learn how to acclimatise to, these are altitude, temperature and time change.
At altitude there is reduced air resistance, suggesting an advantage in activities involving speed, i.e. sprints. The force of gravity is reduced, suggesting an advantage where relative and maximum strength is critical.
Some of the immediate effects of exposure to altitude are increased breathing rate, increased heart rate, giddiness, nausea, headache, sleeplessness and a decrease in VO2 max. The total effect of these adjustments is a reduction of work capacity.
The long-term effects of continued exposure to altitude include: increased erythrocyte volume, increased haemoglobin volume and concentration, increased blood viscosity, increased capillarisation, continued lower V02max, decreased lactic acid tolerance and reduced stroke volume.
For short-term training at altitude, the various benefits associated with it can be offset by other fundamental drawbacks such as poor facilities, strange diet, different surroundings and homesickness. Benefits must be weighed against these limitations, plus those created by time change and problems in travelling to the training venue.
On return from altitude training performances at sea level appear to peak between the 19th and 21st day and then again between 36 days and 48 days performance improves.
Data collected from a variety of elite endurance athletes from a variety of sports have shown that training at altitudes between 1800m and 3000m promotes improvement in endurance-based activities made at sea level. At these altitudes, it can take an athlete up to three weeks to acclimatise.
The ability to perform a vigorous exercise for long periods of time is limited by hyperthermia (overheating) and loss of water and salt in sweating. Athletes should know the hazards of vigorous exercise in hot, humid conditions and should be able to recognise the early warning symptoms which precede heat injury.
The circulatory system functions first to deliver nutrients to the working tissues and remove the waste products, and secondly to regulate the transfer of heat from active muscles to the body surface. It is because of this added demand on blood flow that body temperature regulation, and circulatory capacity, are significantly influenced by the environmental temperature and humidity. When performing in warm, humid conditions the circulation cannot both supply nutrients to muscle and regulate body temperature to the complete satisfaction of the body. As a result, the athlete's performance is impaired, and overheating becomes a serious problem.
Low levels of dehydration can impact performance and it is claimed that a loss of 2% body weight (1kg for a 50k athlete) can reduce performance by 10 to 20%. (a 120 seconds 800m reduced to 132 to 144 seconds).
Two factors influencing early fatigue and impaired performance in all types of sports are the depletion of the body's levels of carbohydrate and fluids. Athletes should consider the use of sports drinks to replace these.
HEAT STROKE is one of the few potentially lethal complications of sport in a healthy individual.
When we travel in an easterly or westerly direction, for every 15 degrees of longitude a time change of one hour occurs. The general effect of this time change is upset to those body functions which are time-linked, e.g. sleeping, waking, eating, bowel and bladder functions. The body will gradually adjust, and a minimum of one day stay for one hours' time change is regarded as a basic necessity. Travel by air also has an effect on the body. e.g. digestion upset, swelling feet and dehydration.
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About the Author
Brian Mackenzie is a British Athletics level 4 performance coach and a coach tutor/assessor. He has been coaching sprint, middle distance and combined event athletes for the past 30+ years and has 45+ years' experience as an endurance athlete.
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