Keeping Cool on Your Ride: Tips for Staying Hydrated

After many years of pushing my body, I have learned to listen to what it needs and try to treat it better. I remember after one hard work-out about 10 years ago when I came home quite dehydrated and while drinking a glass of water I passed out—bam!—right on the floor. I since learned that part of my problem was my low blood pressure became even lower with dehydration. I also learned the hard way that race performance was also negatively affected by dehydration. In the heat, dehydration can lead to heat exhaustion and worse.  (While hyponatremia or water-intoxication can be a problem with marathon runners—especially women—it has not been found to be a nearly the problem with cyclists, so I won’t be discussing it here.)

For cyclists, the question of how much water to bring, how much to drink and whether we ought to add powders or tablets to our water is a question many of us struggle with. Beth and I have been winging it for years but we wanted to get expert advice so we met with Kristi Spence, a sports nutritionist with an Olympic-level athletic background. Although I have sought information from other sources, much of this is from her.

According to Kristi, hydration is important because a loss of as little as 2-3% of body weight from water can result in decreased performance. How much fluid a cyclist needs is influenced by gender, age, body mass, outside temperature, sweat rate, climate, altitude, etc. You get the picture. I have included Kristi’s method for figuring out sweat rate, which is the most accurate way to figure out how much YOU need to be drinking on your next long ride. (Here’s a follow-up article specifically about hydration and altitude.)

IF your bike can't accomodate 2 water bottles, you'll want to buy another water bottle and cage or invest in a back-pack hydration system such as a CamelBak.

Hydration for the Long Ride: the Ideal

Pre- ride and especially before a long ride or competition: At minimum, drink about 16 oz. (+/-) about 90 minutes before ride. For an intense training session or competition such as a longer triathlon, you should start hydrating about 4 hours prior.

During your ride: This is very individual and can vary with weather conditions, but a general rule of thumb has been to drink a 20 oz. bottle of water each hour. You can use that as a starting point and adjust according to your sweat rate (see below). If you are adapting to a new environment with heat, humidity or elevation, you should drink more.

Après-Ride: Quench your thirst! In the hour following your ride, drink another 10-20 oz. If you know your sweat rate, aim to replenish 150% of lost fluid afterwards. (And it is a good idea to monitor your urine color—pale yellow is the ideal—and frequency.) Being well-hydrated helps in nutrient transportation and can help your body recover from intense training.

Day to Day: Kristi advises the young athletes she works with to get into habit of drinking a full 16 oz. glass of water (or milk or juice) at every meal.  If you do that at minimum, you will at least have that to fall back on. Eating soups and fruits can also help add to body’s hydration. Get into the habit of carrying a water bottle around with you so you can drink as needed.

When to Use Sports Drinks

Basically, sports drinks are composed of water, sugar and electrolytes. When you sweat you lose sodium, potassium and magnesium and these drinks should replenish them. The sugar in sports drinks is to help keep your energy levels up. You can use sports drinks before, during and after an intense or long ride (over 1½ hours.)

• 1. Hydration
• 2. Provide fuel for muscles (carbohydrate)
• 3. Provide electrolytes
• 4. Some sport drinks offer protein. This is not essential during exercise, but is important for recovery.

Measuring Sweat Rate… Since everyone sweats differently

• Step 1: Weigh yourself with your cycling clothing on (no shoes) just before your long ride.
• Step 2: Keep track of all fluids you drank during the ride.
• Step 3: Weight yourself after the ride with the same clothing
• Step 4: Find the difference and convert it to ounces (1 lb. =16 oz. or 2 cups of fluid)
• Step 5: Add ounces you consumed during training.
• Step 6: Determine your hourly sweat rate: divide total ounces lost by hours of training.

Example: Jane rides for 2 hours and drinks 20 oz.

• Pre-Ride Weight: 145 lb.
• Fluid on Ride: 20 oz.
• Post-Ride Weight: 142 lb.
• Difference: -3 lbs. (in ounces 48 oz.)
• Add Ride Fluids: 48 oz. + 20 oz. = 68 oz. (8.5 cups)
• Sweat Rate: 68 oz./2 hrs = 34 oz/hr or just less than 4 cups an hour

Next time Jane goes out for a 2-hour ride in similar conditions, she ought to aim to drink about 3/4 of what she might lose while on her ride, so at least 3 cups an hour. She can replace the rest post-ride.

Keep the water in your hydration pack palatable enough to drink on a hot day by adding plenty of ice.

A Few More Questions

Does the Temperature of the Water Matter? That lukewarm water in your water bottle is less palatable and you are less likely to drink what you need to stay hydrated. There is one other advantage with a nice cool drink: cool fluids (45-55 degrees F) actually empty quicker from the stomach and reduce body temperature. To keep your liquids nice and cool, freeze the bottles partially or use insulated bottles. For backpack hydration containers, fill them with plenty of ice cubes. Still, the ideal is cool liquids, they should not be icy-cold when you will be drinking them.

Why Do I Need Sodium? If you are riding in hot and humid conditions or you sweat heavily and you can actually see the dried salt on your skin after a workout, you’ll want to replace that sodium.  A pound of sweat contains between 400-700 mg. of sodium. As always, how much sodium you lose is different than another and as you become acclimated to the heat, your body will become more sweat-efficient and you will lose less sodium. What is the danger? As you become sodium depleted, you will not absorb fluids as efficiently in the stomach and the result will be muscle cramps and fatigue.

What is the Best Use for Nuun, and Other Electrolyte Replacement Tablets? They work best for long endurance exercise or workouts in heat. You can throw them into a jersey pocket and add to water you get along the way to replace electrolytes.