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RECENT RESEARCH EXPLORES THE RELATIONSHIP BETWEEN

HEAT AND ALTITUDE FOR

HIGH PERFORMANCE SPORT NANCY REBEL, MLIS SIRC

W

ith the Olympic and Paralympic Games in Rio de Janeiro, Brazil quickly approaching, environmental factors that may effect athletic performance are of significant interest. Reflecting the theme of this issue we take a look at how heat and altitude have individual and combined effects on athletes and their ability to achieve optimal performance. Though it is the middle of winter in Brazil, the temperatures in Rio for August and September usually average around the mid 20°C with relative humidity levels approaching 80%. The city of Rio itself is right at sea level, however other parts of the city can see elevations in the 1,000-2,000m range. The Games in Rio will show how athletes from different geographical regions have adapted to the climate and location of this Brazilian city.

Heat’s Effects on Athletic Performance Hot and humid environments are experienced differently by athletes according to a variety of factors including their individual physiology and where they are used to living. Olympic and Paralympic athletes may also have to adapt to heat and humidity as a result of medical conditions and/or impairments affecting their thermoregulatory processes. In general, hot environments have been known to manifest in athletes by a decrease in strength, power, speed, endurance and consequently sport specific neuromotor skill performance (Bergeron et al., 2012). The magnitude of the effects of heat on performance is usually dependent on the duration and intensity of the performance. Recommendations for athletes to combat possible negative effects of exertional heat conditions include: maintaining adequate hydration (prior to, during and recovery)

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and sodium level monitoring; progressive physiological adaptation or acclimatization (1-2 weeks); adaptation of warm up routine to incorporate adequate cool down before competition to reduce core temperatures; and design and wearing of appropriate clothing/ uniforms to maximize sweat evaporation. [Additional detailed information on exertional heat illnesses can be found in the NATA Position Statement summary on page 20 of this issue.]

Altitude’s Effects on Athletic Performance Short term effects of high altitude: lack of oxygen causing increased breath rate (in some cases hyperventilation) which can also lead to respiratory alkalosis (inhibition of the respiratory centre to achieve the necessary respiration rate); increased heart rate, decreased stroke volume and suppression of non-necessary bodily functions.

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Long term acclimatization: Compensation for respiratory alkalosis through bicarbonate excretion by the renal system, which allows adequate respiration to increase oxygen without risk of alkalosis. Lower lactate production, decreased plasma volume, increased red blood cells, etc. For those living a significant period of time at high altitudes: the higher the altitude the better the oxygenation of the blood, enlarged lung volumes throughout life, and a higher capacity for exercise. Implications for Athletes: • Higher altitude means less atmospheric resistance for sprint events, long jump and triple jump meaning better performance; for endurance athletes, it means less oxygen in the blood generally decreasing performance. • Though acclimatizing an individual to a high altitude also generally means a better performance at lower altitude,

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