Last summer Dennis and I and Rex and Michele West had a very hot ride home from Tulsa. By late in the afternoon we were headed south on I45 in temperatures around 100 degrees, and all four of us were feeling the effects. Stuck in a traffic jam we were finally able to bail off of the freeway north of Conroe and get into some shade. We made it home safely, but since the hot weather is upon us again it seemed appropriate to discuss techniques for riding in the heat.
Below are some excerpts from David Hough’s book “Proficient Motorcycling” along with commentary from your Rider Educator.
David writes: “The body has sweat glands to keep the skin damp. The evaporating sweat sucks heat from the skin, and transfers it to the air. Of course sweat is primarily water, so it’s critical to keep replenishing the supply. That's one reason why we need to drink about a pint of water every hour during hot, dry conditions. One problem for mo-to cyclists is that at highway speed, the sweat glands may not keep up with the evaporation. Or, if the sweating uses up too much water, your body temperature regulating system goes on the fritz, like a dry battery.”
In high temperatures we need to stop every 60 or 70 miles to cool off and drink water. Riders who can carry beverage holders on their bikes should keep them filled with ice water. NK
“The heart responds to increasing heat ("hyperthermia") by increasing the heart rate to pump more blood into those enlarged blood vessels. As the air temperature rises, heart rate can increase 50% to 70% faster than the normal resting rate. The increased flow causes blood pressure to drop, and blood flow is shunted away from muscles and brain, towards the skin. Consider the implications of those changes on a motorcyclist. The lowered blood pressure reduces muscle control and brain activity.
“The human body won't take much of an increase in core temperature without complaining. The symptoms of overheating are leg cramps, tired muscles, headaches, dizziness, and even fainting. The various symptoms are trying to tell you how overcooked you're getting.”
“If ambient air temperature is lower than body temperature, excess heat can be absorbed by the air. But if the air gets hotter than the skin, the increased blood flow simply soaks up more heat from the air and pumps it back to the core.”
That’s one reason why we keep covered up with long pants and sleeves when we ride in the heat. NK
“People often react to hot weather by removing clothing. That helps cool the skin--providing air temperature is less than body temperature. Even if the air is 89F, the air will absorb heat from your skin (assuming your body is around 99F). Now, consider what happens when you curl your fingers around a hot cup of coffee. Your skin rapidly absorbs heat from the cup, because the cup is hotter than your hand. The same thing occurs when the air temperature is hotter than your body temperature.
“You may think your body is hot at 99 F, but it’s "cold" compared to air at 110 F. If you expose your skin to air that’s hotter than you are, your body just soaks up more heat.
“Once air temperature climbs above 99 F, the best way to keep from getting cooked is to keep your insulation on, and the vents closed. Wouldn’t it make sense to crack your visor when it’s really hot, or at least open up the helmet vents? Nope. Any hot air allowed to reach your skin will heat up the skin, not cool it down. Inside my helmet at 110F, I’m sweltering, but the temperature is probably under 100 F. That crushable helmet liner inside the shell is there to cushion my brain against impacts, but it’s the same expanded polystyrene foam they use to make insulated picnic coolers. So, the helmet actually pro-vides insulation against the hot air.
During the last hour of our ride home from Tulsa I experienced this same effect. Desperate to feel cooler, I opened my face shield for more air flow. But the incoming air, super-heated from the asphalt was heating me up even more. I continued on with my face shield closed.
“When water evaporates, it cools down. Cooling the skin cools the blood, which cools down the whole body. Evaporative cooling works best on areas of the body where there are large blood vessels close to the skin: the groin and the neck.
Get a Cool Collar or something similar to wrap around your neck for evaporative cooling. Dennis has modified a couple of standard bandanas by folding them in half and stitching a pocket in them to hold ice. He ties them around his neck, and the melting ice helps keep his long sleeve shirt cool, too. NK
“The bad news is that evaporative cooling only works well in dry climates. When the humidity is al-ready high, (you're 99/99 in South Texas in August--99 degrees and 99 percent) neither perspiration nor the water in your neckband evaporate very well. Limited evaporation means limited cooling. So look to ride early in the morning when it’s cool, and rest in the shade in the afternoon.
So, when it’s really hot, keep your jacket on, and soak down your T-shirt. Wear a wet neck cooler, and keep dribbling water on it. If you’re getting too hot, or start feeling any hints of muscle cramps or heat exhaustion, don’t just keep riding. Take steps to cool down while you’re still thinking clearly. Take a break in the shade, or stop at a convenience store and buy a bag of crushed ice to stuff inside your jacket. Or best of all, call it a day and get off the road for a cold beverage with your friends!