Drying Out

Text: Robert Smith • Photography: Robert Smith

Until someone invents an air-conditioned bike, motorcyclists will have to enjoy - and endure - the elements. And while hypothermia is a potential hazard at the lower end of the temperature scale, there's an equal danger lurking when the thermometer soars: hypohydration.

Hypohydration (often called dehydration) means, literally, insufficient water. A condition that almost every motorcyclist will experience at least once, it can reduce physical strength and stamina, cause drowsiness or dizziness, and affect mental judgment - any of which could seriously impact your ability to ride safely.

If you spend any time in the U.S. during the summer, you're going to get hot; but as we are warm-blooded animals, our bodies want to maintain a steady core temperature. When the temperature rises, the body's response to the extra heat is to sweat, cooling itself by evaporation of the surface moisture. The higher the temperature, the more profusely we sweat.

How much water loss are we talking about? Our bodies like to regulate fluid levels to within plus or minus 0.25 percent body weight, or about eight ounces for an average size male. A loss of two percent of body mass, say a quart of moisture, will cause hypohydration and the symptoms that go with it.

Riding a motorcycle in hot conditions substantially reduces body fluid through sweat, either because you're overheating inside your riding suit, or because the hot air blowing through your vented jacket is rapidly evaporating surface sweat. Either way, you can become dehydrated quite quickly.

When we get thirsty on a ride, most of us stop and take a drink. Or maybe we have one of those water-bladder backpacks for drinking on the move. Problem solved, right? Not really - because humans, uniquely among animals, are not properly wired to know when they need to drink more. And even when we think we have consumed enough water, it's unlikely we've taken in sufficient quantities to prevent all of the effects of hypohydration. In a hot, dry climate, and without undue physical exertion, your body may need to drink as much as a gallon of water a day to replace lost fluid!

One summer, I was riding the 300-mile route through California's San Joaquin Valley in July, returning a SV650S to Suzuki in Los Angeles. The air temperature was over 110, and the blazing sun beat down relentlessly. In those conditions, I could have been losing close to a pint of water an hour.

I remember stopping a couple of times to grab water in a gas station, but not being able to swallow more than three or four gulps before my stomach felt overfull. So I'd stow the leftover water and carry on. (It didn't help that the water was always ice cold.) By the time I got to L.A., I was completely wiped out, yet I didn't feel particularly thirsty. It was later when waking with a parched throat and a fierce headache that I realized how dehydrated I had become.

That illustrates two quirks of human metabolism that can get us into trouble. First, our thirst-o-meter is not linear - we don't necessarily get thirstier as we lose more moisture. That's why it's easy for us to get hypohydrated, because paradoxically, we may even feel less thirsty as our fluid level drops.

Secondly, most animals, including our canine companions, have the ability to completely rehydrate in one drink, maybe lasting minutes. Unfortunately, humans can't do that. When we take a drink, most of the water is absorbed through the small intestine, and the stomach can't hold all the water we might need to fully rehydrate. It may take hours to swallow enough water for full rehydration, and along the way we may well feel bloated and even nauseous.

So, when adding these factors together - the rapid loss of fluid through sweat while on the move, our relative slowness to detect hypohydration, and our inability to quickly rehydrate - it's easy to see why hypohydration is a big issue for motorcyclists.

Seven-percent solution

ydration should be a major consideration when planning your next motorcycle trip, even if you're not going anywhere excessively hot. Probably the best answer is one of those water-bladder backpacks with a flexible drinking tube and one-way suck-action valve. Camelbak is perhaps the best-known brand, but most outdoor outfitters stock alternatives. Plan to drink 10 to 20 ounces of liquid an hour. Drink more than you think you want to. It's difficult to drink too much.

Good old water is still the best liquid for rehydration. But you might find an isotonic mineral-glucose drink like Gatorade or one of its competitors more palatable, and even better for you if diluted with more water. It's true your body does lose salt while sweating, but most of us get more than enough in our diets to replace the salts lost. And salt tablets will only make hypohydration worse.

Lashing a coffee mug to your handlebars isn't the answer either. Nor is dosing yourself with any variety of the new "energy" drinks. These choices contain lots of caffeine, and energy drinks are usually high in sugar content too, both of which will exacerbate hypohydration.

So how can you tell if you're not drinking enough? Suddenly realizing it's been more than a couple of hours since your last pee break may be a clue; and also if your urine is deeply colored, or if you experience discomfort while urinating.

One tenet of the macho sensibility current in the bad biker community holds that carrying water or stopping for a drink (unless it's in a bar, of course) is somehow wussy. I've also been told the wives' tale that spending a lot of time in a hot climate alters your metabolism to such an extent that you don't need as much water. The first idea is downright irresponsible, and the second is utterly false.

Drinking and riding is fine. In fact, it's a really good idea - as long as that drink is water!