Drinking and Eating - What's Up With That?

Cycling in Hot Weather. The air temperature at Death Valley in mid-May may be hot. Very hot. More than two-thirds of the energy expended during cycling is used to regulate body temperature. Be prepared mentally and physically to deal with the physiological hardships associated with exercising in heat. First, train in hot weather. Second, lose the cycling gloves and windbreaker. A generous amount of body heat is lost through your hands, so let it go. Minimize your chances of overheating by wearing clothes made from materials that promote air circulation—natural fibers—and preferable are white in color. Third, during the ride, don't remove soaked clothing. Wet clothes, unlike dry, function as a swamp cooler. Finally, alternate moderate-to-moderately intense cycling intervals with intense-cycling intervals during the ride to help maintain internal temperature equilibrium.

Water—Your Most Important Nutrient. Water is the single most important nutrient in your arsenal to cope with heat stress. Water makes up 40 to 60% of your total body mass and 65 to 75% of the weight of a single muscle. The physiological functions of water are many. Like the liquid streets of Venice, your internal transportation highways consist of water-based fluids. In addition, every chemical reaction occurring within your body depends on water, including the diffusion of oxygen and carbon dioxide within your lungs. Your internal water acts as a big heat sink, absorbing large quantities of heat and allowing only small changes in internal body temperature to keep you comfy at 98.6°F. Water is noncompressable, and therefore provides structure to body tissues. Water functions as an in-house lubricant to keep joints slippery so bones don't grind against each other.

Dangers of Water Loss. Water balance inside your body is precarious and can be upset when you cycle by losses through urine, feces, and sweat and as vapor through expired air. During strenuous cycling, about 3.5 milliliters of water are lost via the lungs each minute—which equals slightly less than one cup of water each hour just from breathing!

The most serious consequence of profuse and prolonged sweating is loss of body water. How much water is lost depends on the duration and intensity of effort as well as the relative humidity of the air. Hot, humid air contains more moisture than colder, drier air. The sweat off your skin must also compete for air space with nature's other respiratory by-products. On the plus side, our dry high-desert air can absorb considerably more moisture than the moisture-laden air found in such areas as Florida or Hawaii. In dry air, water is more easily evaporated from your skin into the atmosphere, which in turn keeps your sweating mechanisms functioning at optimal efficiency. However, even small water losses can impact your internal balance and overall cycling performance. Your blood volume is reduced when fluid losses approach 2% of body mass: that's a 3-pound weight loss for a 150-pound cyclist. This reduction in blood volume causes a strain on circulatory function that ultimately impairs your capacity for exercise and ability to regulate your body temperature. Death from dehydration can occur when body water lose is greater than 15%. To make sure this doesn't happen to you, drink fluids constantly and consistently when you cycle, before you are thirsty!

Heat Cramps, Exhaustion, and Stroke. Cramping is defined as involuntary muscle spasms that occur during or after intense physical activity in the specific muscles exercised. This form of illness is caused by an imbalance in the body's fluid and electrolyte concentrations. The key word is imbalance. Your electrolyte replacement drink should not be too concentrated or too dilute. As our childhood pal Goldilocks would lament, it must be "just right." So, use the 1:1 rule. For each bottle of liquid electrolyte fluid you drink, drink an equal volume of plain water. Alternatively, double dilute powdered or commercial electrolyte drinks. The second most common illness associated with high temperatures is heat exhaustion. Heat exhaustion is characterized by a weak, rapid pulse, low blood pressure when upright, headache, dizziness, and general weakness. Sweating may actually diminish, but body temperature remains stable. Because you've lost too much water too fast, circulatory adjustments are ineffective at cooling and compounded by fluid depletion. If this happens to you, your cycling day is over. Stop and find a cool place to rest. Drink whatever fluids are available and try to get more from other cyclists. Flag down the sag wagon and enjoy the scenic drive to Lone Pine. Continue to drink fluids throughout the evening, in addition to eating a good meal. Heat stroke is the third member of the fluid-depletion triad and can be deadly. Heat stroke is a failure of the body's heat-regulating mechanisms caused by an excessively high body temperature. Sweating stops, your skin becomes dry and hot, and your body temperature skyrockets. If untreated, you will die. If this happens to you, stop cycling immediately. Send for help via another cyclist or the sag wagon. Crawl to the closest speck of shade, even if it is only a mere shadow cast by a bush or boulder. Lie down, relax, and elevate your legs. If you have anything to drink, drink it now. Try to get additional fluids from other cyclists. When the sag wagon arrives, ask for something—anything—to drink and keep drinking as long as possible. Then ask your rescuers to rub you down with rubbing alcohol if possible. Next, check into the nearest hospital. If a motel is more convenient, jump immediately into the swimming pool. Have a friend check you in to a room. Have a second friend fill the bathtub with lots of ice and water. Have your first friend asset you into the ice-water bath. Immerse yourself in the ice-water bath as you continue to drink fluids. Seek follow-up medical attention at the nearest hospital.

How To Drink. If you're running low on water between stops and you're blazingly hot, drink whatever water you do have rather than pouring it over your head. Water does your body more good on the inside than on the outside. On the first day of the ride, drink 20 ounces of fluids 2 hours before the ride. Drink an additional 12 ounces of fluids 15 minutes before the ride. Drink at least 8 ounces of fluids every 15 minutes or 32 ounces (two 16-ounce water bottles) each hour you cycle. This requirement may increase if the temperature is greater than 90°F. I drink one bottle of water and one bottle of Cytomax every 10 miles (between rest stops), in addition to three cups of water and/or Cytomax shoved at me at the rest stops when I'm pausing. Cold liquids leave the stomach and are absorbed into the rest of the body faster than warm liquids. Insulated water bottles are available for $9—a very wise, low-cost investment for optimizing your performance during the ride. The rate at which liquids leave the stomach is slowed when ingested fluid is concentrated with electrolytes or simple sugars. For example, a 40% sugar solution is emptied from the stomach at a rate five times slower than that of plain water. The double-dilute rule will help alleviate this problem. As a guideline, electrolyte replacement drinks should also contain 4 to 8% carbohydrate. Research shows little difference exists between liquid glucose, sucrose, or glucose polymers (starch) as the ingested carbohydrate source during exercise.

The Best Part: Eating! Cycling is one of the best activities to undertake to sustain lifelong weight control. On an average, the daily caloric intake for amateur female cyclists is 2600 calories; for men, 4600 calories. An active athlete needs 23 calories per pound of body weight each day to provide enough calories for optimal athletic performance. Now that's some serious eating. Most of us don't eat this much each day, but may approach this average if calculated on a weekly basis. Health professionals recommend that carbohydrates supply at least 60% of these calories; however, many cyclists feel and perform better with diets that contain carbohydrate, protein, and fat in a 50:30:20 ratio.

Pre-Event Eating. The main purpose of the preride meal is to provide you with adequate energy and ensure optimal hydration. A preride meal containing 200 to 350 grams of carbohydrate 3 to 6 hours before exercising has the potential for improving performance by maximizing muscle and liver glycogen storage as well as providing glucose for intestinal absorption during exercise. A general guideline is to eat small servings of familiar foods. DO NOT EXPERIMENT. Because it's going to be a long day, I also include a small serving of good-quality protein, such as eggs, for my preride meal, which assists carbohydrate assimilation. If cooking is not an option, try instant oatmeal with powdered milk, cottage cheese, yogurt, or a turkey and cheese sandwich. Allow enough time for adequate digestion before the event. Simple sugars are absorbed into your blood 20 to 30 minutes after eating; complex carbohydrates, 1 to 2 hours; protein, 90 minutes to 3 hours; fats 2 to 4 hours. Milk sugar (lactose) takes slightly longer than glucose (30 to 60 minutes) because digestion is slowed by the presence of protein and/or fat in dairy products. Commercially prepared liquid meals offer an alternate, effective approach to preride meal feeding.

Carbohydrate Loading—A Way To Increase Glycogen Reserves. A particular combination of diet and exercise can result in significant "packing" of muscle glycogen. The end result is an even greater increase in muscle glycogen than would occur with simply consuming a carbohydrate-rich diet. Carbohydrate loading is appropriate for physical activities that last longer than 1 hour and are performed at high intensities. For cyclists that prefer to carbo-load, professionals recommend following a "modified" carbo-loading plan that will increase glycogen stores by 30 to 40% above normal and minimize the negative aspects of the regime. To carbo-load via this manner, train at a high aerobic intensity for 90 minutes and gradually reduce or taper the duration of exercise on successive days. During Stage 1, ingest approximately 100 grams or 400 calories of carbohydrates; in Stage 2, increase this amount to 400 to 625 grams or 1600 to 2500 calories.

Exercise time and carbohydrate content of diet one week prior to event.

Sample menu plan for carbohydrate depletion and loading diets preceding an endurance event.

Event Eating. Expert advice is to eat foods that contain sugar—such bananas, oranges, figs, dates, low-fat cookies, and energy bars—at a rate that supplies 30 to 60 grams (120 to 240 calories) of carbohydrate each hour. These foods must be ingested at least 30 minutes prior to the time when fatigue would normally occur without a carbohydrate supplementation. One valley cyclist makes it much easier: start eating and drinking the minute you leave Stove Pipe Wells and don't stop until you get to the top of Mt. Whitney. It's invaluable advice. Some valley cyclists swear by liquid glucose supplements, consuming as much as 12 packages during the first day of the ride. Others shun sweets, preferring instead the salty sustenance of turkey, salami, cheese, crackers, and peanuts. Still others choose good old pb&j on bread. What you eat is not nearly as important as the fact that you do indeed eat. Eat whatever you can carry in—and easily retrieve from—the pocket of your jersey. Eat small amounts (one or two bits) continuously throughout the day. Eat whatever appeals to you and whatever you will put in your mouth, chew, and swallow.

Post-Event Eating. Follow the general rule of consuming 50 to 75 grams (200 to 300 calories) of carbohydrate as soon as possible after the ride, up to 500 grams (2000 calories) within a 2-hour period. Now is a good time for Cheetos, grape juice, squaw bread, cheeseburgers, pizza, and ice cream, and anything else not bolted down. So eat, drink, mingle, and be merry, for tomorrow, you will ride.

A Final Ponder: Enjoy the beauty of our national parks and the company of fellow cyclists. Be sure to thank the many volunteers who make your cycling day possible!