The human body is a fantastic thing. So many critical systems - circulation, pulmonary, digestive, muscular/skeletal, etc., all working in unison, and all controlled by an operating system that never crashes. The most advanced human-engineered machines are primitive by comparison.
Take, for example, the cooling system. When it gets hot, sweat glands open (automatically... you don't even have to think about it) and deposit water on your outer surface, where evaporation provides cooling power. Conversely, when it's cold, the glands pinch shut, and you get "goose bumps."
(Based on observation, I'd say there are a lot of people whose focus in life - whose definition of provident living - is to keep those sweat glands from ever opening. Unfortunate.)
What you do have to think about is keeping that water tank filled up. On a hot day, if you're exerting yourself, you can lose 8+ ounces of fluid every 15 minutes. And if you're riding along on a bicycle, you don't even notice, because most of it evaporates. If you get thirsty, it's too late. You have to think about drinking before you get thirsty.
I know from experience. When I'm riding on a scorching summer day, sometimes I wonder if I'm even sweating at all... until I stop at a traffic signal. 20 seconds later, water is pouring off, and puddling underneath. Yep - I'm sweating.
What are the risks of getting dehydrated?
- increased heart rate (the circulatory system provides backup, but isn't nearly as efficient)
- more perceived exertion (riding gets harder)
- decreased performance
- increased body temperature
- cramps (The only time I ever get leg cramps is after a lot of hard riding on a hot day.)
If you don't take care of it, you can develop some serious problems and risk your health:
- heat stroke
- heart attack
So... what to do? Here's what I do.
I drink a lot of water... all year 'round, but particularly in the summer. (A guy at the office told me I'm probably rusting my innards! I keep a 32-ounce glass at my desk, and drain it 4-6 times a day.)
A half-hour or so before I ride, I'll consciously tank up on water (20-32 ounces).
I normally only carry one water bottle on my bike, and sip regularly as I ride. If I know I'm going on a longer ride (more than an hour), I'll take two bigger-size bottles. If they get low, I start watching for a place - gas station, convenience store, public restroom, etc. - to refill. I'm not fussy, and generally people are very willing to share a bottle's worth of water.
Does the water get hot? You betcha! If it's 98 degrees out, the water is 98 degrees. But it's wet. And after 20+ years, the warm water goes down just as easy as cool. (And easier than cold. I don't like drinking cold water on a hot, hot day.)
If my route takes me by a canal, or river, or creek, on a scorching day I'll stop and take my shirt off and soak it with cool water. It is absolutely amazing how much difference that makes... for 10 minutes or so until all the water evaporates.
If I know I'll have ample opportunity to refill my water bottles, I'll also use them to supplement the water-cooling, by squirting water on my head (through the helmet-holes), over my shoulder onto my back, etc. (Same effect as the canal-break, but not as dramatic.)
When I finish my ride, I love to soak my head and trunk with the hose, and drink up. Sweet relief! (I frequently say, only half-jokingly, that the reason I enjoy riding a bike so much, is because it feels so good to stop!)
What I don't do:
- Drink soda. (I'll have one every so often, but never to quench thirst.)
- Use a "hydration pack." Some people use the back-mounted packs, but that's always been a bit too complicated for me. I love simplicity. (They make sense if you're riding for hours, and no opportunity to refill your bottles.)
- Drink Gatorade or some other special drink. Nothing wrong with that, I'm sure... but water has always worked for me. (If I need salt, I'll eat some potato chips!)
My brother and sister-in-law used to live in Nampa. Many years ago on a hot summer Saturday, I rode over there. They weren't home, but a hose was running in their front yard, onto the lawn. I drank, and drank, and drank out of that hose. So fine! Later I told them. They said, "You don't want to drink that water! It's pressurized irrigation water, out of the canal!" Doh! Fortunately, I never suffered any side effects... and it sure was cool!
Drink [water!] to ride... ride to drink!