This article originally appeared in the Capital Bicycle Club Newsletter August 2013
Huzzah! Huzzah! The clouds have parted and allowed for some really great summer cycling. For most of us, that means longer rides and the challenge of staying hydrated while getting the right amount of fuel to keep us enjoying our efforts. One of the problems that cyclists may encounter on their longer rides is that they take on a higher calorie load than their body can actually digest in an effort to stay hydrated simply because they are drinking more volume of their chosen sports drink. The result may be very uncomfortable symptoms such as bloating, nausea, diarrhea, or vomiting.
For a large part of the year, our cycling trips are shrouded in mist, rain, clouds, and cooler temperatures. During those rides, our sweat rates are lower than they are in hotter weather (in case you haven’t noticed!) Once the weather changes, and demands for staying cool increase, our bodies start producing abundant sweat to keep us from overheating. The body operates best in a fairly narrow temperature range, and sweating is one of the ways that it tries to regulate the stress of exercising in the heat.
Although everyone adapts differently to heat stress, here is an example that may help when you think about putting this information into action: On a 100 mile ride in 50-70° F you may sweat at a rate of 0.8 Liters per hour. If you complete the ride in about 6.5 hours, you’d need roughly 4.6 bottles of water (20 oz.) to keep yourself hydrated. If you ride that same 100 mile ride in the same amount of time, but now the temperature is 70-90° F, your sweat rate may jump up to 1.5 Liters per hour or more. To stay hydrated under these warmer conditions you’d need to drink about 10.5 bottles (20 oz.) to stay hydrated. It may sound like a lot, but consider that Alan Lim, sports physiologist, has seen professional riders complete a 5 hour stage in the Tour de France, while drinking up to 25 bottles of water. Regardless of this high quantity, they still showed significant dehydration at the conclusion of the stage!
One of the solutions to stomach upset that Lim has come up with is that he keeps the concentration of his sports drinks to approximately 4% or 100 calories per 20 oz. water bottle. That’s about the top end of what we can reasonably absorb in liquid form without upsetting the balance of concentration of water in the body (i.e. diarrhea!) If you are staring down the task of drinking 10 or more bottles during a day, paying attention to a detail like this might make or break your day of cycling.
Related to this conversation about balancing hydration with fueling is to consider how much of your food is coming from bars, gels, and powders. For most of us, we’d feel awful if we sat around the house and ate these kinds of foods all day long. I will admit that even my sweet tooth gets tired after a while and wants to eat something else. One benefit of eating real food while you ride is that it stays in your stomach longer while it digests and therefore provides your body with fuel at a slower, steady rate to give you sustained energy. It also takes the pressure off of having to drink all your calories from your water bottle.
Hopefully these tips serve you well and keep you on your bike instead of along the roadside with an ill stomach. See you on the road!