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  Last updated: 11/15/2015

Cycling Challenges in Temperature Extremes

Temperature extremes threaten you core temperature - which in turn effects optimum functioning of all our cellular functions - brain, heart, as well as muscle contraction. At high temperatures there is the cumulative effect of the ambient temperature adding to the heat you develop from muscle contraction - both aligned to increase your core body temperature. Add in humid conditions which decrease the potential to shed heat with sweating and evaporation and the problem magnifies. At the other end, extreme cold, the challenge is to minimize heat loss aggravated by both a wind chill effect as well as the return of colder blood from your extremities. Again threatening to lower your overall core temperature below its physiologic optimum.

We know that riding at the extremes of temperature will impact your performance. This article shows the negative effects of both high and low ambient temperatures. To quote "The optimal aerobic endurance performance wearing a cross-country ski racing suit was found to be -4 and 1C, while performance was reduced under moderate warm (10 and 20C) and cold (-14 and -9C) ambient conditions." Since it is unlikely the temperature had an impact on equipment, this reflects a decrease in the power developed by athlete.

And in cycling, there are also equipment impacts to consider. This website shows us how low temperature impacts on both air resistance and the rolling resistance of your tires slow times compared to a similar amount of effort (power output) on a summer outing.

Why the lower power output in extreme temperatures?

Mitigation of Extreme Heat and Humidity

A number of techniques have been shown to be of benefit. In competition a number of studies have shown the benefit of precooling so the athlete starts the event at the lower end of their ideal core temperature.

For those of us doing recreational riding, drinking a cold beverage provides the easiest solution. delay a rise in core temperature. And it did increase time to exhaustion performance, but just shy of the level defined as "statistically significant". A second study supported the benefit of drinking cold beverages and again demonstrated an increase in performance (this time statistically significant). Bottom line? I add ice to my water bottle, and if I remember, actually put the bottle, partially filled, in the freezer the night before to form an internal "ice cube".

Training and competing in the heat. I recently had a personal encounter with the effects of riding without adequate acclimatization to the heat. I train in the NW (Seattle) but was riding in the Sierras in California. On day 2 of a multi-day ride I had my first cramps (ever) while on the bike. Quad cramps that almost kept me from finishing. It was 95 degrees, we were climbing Emigrant Pass (8000 feet), my gloves were white with salt, and I'm sure I was not drinking enough. Fortunately they had electrolyte powder at the next rest stop, and I took 10 minutes to drink a couple of water bottles or rehydration fluid. And I slowed down. Lesson learned. As I read this recently published article, it definitely resonated. I'll quote a few pertinent sentences.

Mitigation of Extreme Cold

Proper clothing provides the best option, although there is still the overall impact of the general heat loss from breathing cold air as well as the breathability of most fabrics. Put on a windproof barrier and the challenge now becomes prevention of sweating and damp clothing that increases the clamminess with any slowing of pace and internal heat production.

Questions on content or suggestions to improve this page are appreciated.

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