The Heat Cycle

The Heat Cycle

Whether you do it for transportation, leisure, or sport, bicycling is an outdoor activity. And while many of you will avoid or limit riding during cold weather months, you will have trouble finding cyclists who do the same during the hottest parts of the year.


That can be problematic, as hot weather is arguably far more dangerous for cyclists than cold. And those dangers are generally less apparent.


Sweat Equity


The most obvious danger for cycling in hot weather is the impact upon the body. Cycling can be a very rigorous physical activity, and the workout can generate a substantial amount of body heat.


While this fact makes it easier to keep warm in cold weather extremes, it becomes very dangerous in hot weather. The physical exertion of riding not only causes you to heat up, but your body’s defense against overheating – namely, sweating – can cause you to become dehydrated very quickly. 


Worse, hot weather can also mask dehydration, making it hard to recognize when it’s time to stop, rest, and re-hydrate. For example, when the air is humid (as it often is in the summertime), it is already full of water vapor, which slows the evaporation of sweat that cools the body, leaving you hot and soggy. But when that air is hot and dry (as it is in the desert), evaporation happens so fast that you might not even notice yourself sweating. 


This can be very dangerous for cyclists who don’t carefully manage their hydration. Because the body’s cooling process works so efficiently – sweat evaporates and keeps the body cool – cyclists can literally burn through their body fluids without seeming to break a sweat. If cyclists don’t compensate by consuming fluids at the same rate they are losing them, they may not realize they are dehydrated until their muscles start to cramp.


As a cyclist, hydration should be your top priority when riding on hot days. Understanding how your body loses its moisture can be the key to ensuring you do not lose more fluid than you consume.


Risk Assessment


Anyone who performs physical activity in hot weather should be aware of their risk of developing a heat-related illness, such as heat stroke or heat exhaustion. These are very serious and dangerous conditions that can lead to a loss of consciousness, brain damage, or even death. 


But they are also entirely avoidable, so long as one practices safety and uses common sense while riding in hot weather. 


All riders should familiarize themselves with the signs and symptoms of heat-related illnesses, so they know what to watch out for, and can tell when it’s time to stop, rest, and cool down.


In addition to taking precautions against the heat, cyclists should also protect themselves from the sun. It only takes a few minutes of sunlight to cause a sunburn, and the full effect of a sunburn is often not felt for hours after exposure.


But exposure to the sun does not just cause sunburns, it also causes your body temperature to rise just as physical exertion does. So limiting your exposure can help keep your body from overheating as you ride.


Bicycle Health


The good news is that your bike does not face the same degree of risk from hot weather. Unlike you, a bike isn’t going to get too hot from being ridden, and even the hottest outdoor temperatures will not really damage it.


But that doesn’t mean it won’t feel the effects of the heat.


Many bikes have 8 (or so) bearings that allow wheels, pedals, derailleurs, gears, and handlebars to spin to one degree or another. While the faster-spinning bearings (like those in the wheels) may heat up due to friction, they aren’t likely to overheat at the velocities bikes are able to achieve. However, riding hard in hot weather can tax these bearings, and lower the viscosity of the lubricants that keep friction to a minimum.


So even though hot weather won’t damage the bearings, it may limit their lifespan overall. This problem can be exacerbated by dirt or corrosion within the bearings themselves. When bearings become dirty or corroded, they don’t spin freely, and can generate an abundance of friction that will speed up their degradation, potentially causing them to fail or seize up.


Hot weather can also speed up the degradation of tires and other rubber parts, but not in an alarming way. Bikes are simply better kept indoors – and only exposed to the elements while being ridden.


Being a responsible rider means taking good care of your equipment, and for cyclists, that includes the engine that powers the bike – your body itself. Whether riding in the extreme heat, cold, or anywhere in between, cyclists need to understand the risks and be aware of their physical limitations.


Ride safely.