Note: This article is part 1 of a two-part series on hydration and sports drinks.
To ensure proper hydration, sports drinks are often consumed by many professional and amateur athletes before, during, and after exercise to replenish water loss through sweat. Although consuming liquids is vital to avoid dehydration and safeguard health, sports drinks are far from being the energy drinks commonly – and often inappropriately – promoted in advertisements.
According to Beverage Bird, “Energy drinks are for people looking for a big rush in energy and concentration. Sports drinks are made with athletes in mind and focus on replenishing fluid and electrolytes.
“Both drinks contain a lot of sugar, but energy drinks also contain caffeine, which is not found in sports drinks. While sports drinks focus on better hydration, energy drinks can cause dehydration.”
How the Human Body Uses Its Fluid Reserves to Cool Itself after Exercise
AquaVitality notes that water accounts for about 60-65% of total body weight in humans depending on individual percentages of fat weight versus muscle weight. The body’s internal supply of water creates a remarkable cooling system because this fluid reserve is released as sweat through pores in the skin’s surface.
The evaporation of sweat cools the body as the water on the skin vaporizes, releasing calories of heat from the body to environment as liquid is converted into gas. Nearly 580 calories of metabolically produced heat are released per each quart of sweat that evaporates, according to the Journal of Applied Physiology.
High sweat rates during intense exertion in hot and humid weather occur at the expense of fluids. These fluids are vital to maintaining cellular processes within the body, cardiovascular function, and temperature regulation.
The National Council on Strength and Fitness (NCSF) says that dehydration of as little as 2% of body weight is associated with approximately a 10% decrease in exercise performance. Similarly, Precision Hydration says that dehydration of 9% to 10% of one’s body weight (15% to 16% of total body water) can result in heat exhaustion, heatstroke or even death.
The primary goal of fluid replacement during exercise is to maintain blood plasma volume so that sweating can progress at a rate appropriate enough to minimize the inevitable exertion-induced rise in internal body temperature. Regular consumption of plain water or a sports drink during an endurance workout dramatically improves body hydration as compared to the same activity performed without fluids.
Many Athletic Events Have Tents to Treat Athletes Who Become Dehydrated
Now, nearly all sporting events have tents to treat contestants who become dehydrated to the point where their sweat loss greatly exceeds fluid consumption. But this situation wasn’t always the case; international marathons prior to the 1976 Olympics followed a ridiculous policy of prohibiting water stops for the first six miles. Some competitors would subsequently collapse near the end of the race with fever-level body temperatures exceeding 106 degrees Fahrenheit, a level the U.S. Consumer Product Safety Commission considers incompatible with life.
Continual Rehydration during Sports Competitions Is Vital
Because sweat evaporation is the body’s main heat-dissipating mechanism, continual rehydration during competition is essential. Professional football players competing in full uniform on sunbaked astroturf are sometimes given fluids intravenously at halftime to quickly replenish critical fluid reserves. Measures this extreme are not normally necessary during weekend “fun run” races, because excessive dehydration is generally avoidable by oral fluid consumption at regular intervals.
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How to Hydrate Properly
Common sense dictates to be sure to never miss a water stop during a race. Ideally, beverage cups should hold at least seven ounces of liquid, and water stops should be located at least every one and half miles throughout a race’s course.
Cool beverages are best; warmer fluids will pass faster from the stomach into the small intestine and the bloodstream. Drinks that are about refrigerator temperature (40 degrees Fahrenheit) are generally absorbed the quickest.
Consuming approximately one quart per hour is commonly recommended. However, this recommendation varies considerably from athlete to athlete, depending on sweat rate, body size, conditioning level and exercise mode.
Serious competitors should experiment by establishing a fluid ingestion regime during their training and maintain the same fluid consumption strategy during competition. Ideally, do not wait until race day to try out a new sports drink or rehydration timing strategy.
Also, be aware that it is possible to drink too much. Excessive hydration will cause fluid to accumulate in the gut and the need to stop exercising and urinate. Too much liquid will also create you a bloated feeling, abdominal cramps and in very rare cases, water intoxication, according to Medical News Today.
Carbohydrate loading in the days prior to a marathon-type competition is important to race performance, but fluid loading is just as critical but often overlooked. Begin “hyper-hydrating” your body at least three days prior to competition. Also, remember that your body may remain in a relative state of dehydration for hours or even days after the event if considerable weight is lost and you have not consumed enough fluids post-exercise.
Body weight should be monitored daily during intense training/competition. However, it’s important to keep in mind that nearly all weight loss after training and competition will be due to water loss and not fat loss, as many would like to think.
Another way to monitor body fluid balance is to check your urine. Urine that is a dark yellow in the hours and days following exercise indicates you need to consume more fluids. By contrast, a clear, colorless urine indicates adequate rehydration, according to the Mayo Clinic.
Thirst Is Not a Reliable Indicator That the Body Requires Hydration
The liberal consumption of fluids even though you may not feel thirsty during and after exercise is important; the sense of thirst is not a good indicator of the body’s actual needs. Fluids should be available during all practice sessions, and younger and older athletes in particular should be continually encouraged to drink liquids.
Athletes of all ages often forget to drink when their minds become intensely focused on a competition. Coaches of youth sports should be aware that children are more prone to dehydration than adults, due to their smaller fluid reserve and less developed sweat response.
Interestingly, the dehydration “warning” mechanism is surprisingly less developed in humans than in animals, according to Baylor College of Medicine. For example, most animals quit abruptly their exercise when their body temperature exceeds a certain level and later drink back exactly enough water to regain any lost weight. Unfortunately, severely dehydrated humans may continue running even while lapsing into the end stages of heat exhaustion (approaching heatstroke) and later refuse precious fluids at the treatment tent after a race.
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Proper Precautions Will Allow You to Ensure Hydration
The best treatment for dehydration is prevention. Serious heat illnesses due to fluid depletion are one of the few preventable medical problems.
When possible, strenuous exercise should be conducted during cooler times of the day; the effect of local weather on your body can also be checked by reviewing the Wet Bulb Globe Temperature. You should also avoid wearing oil-based sunscreen lotions as they may clog pores and block sweat secretion.
Another option for proper hydration is to exercise in windy conditions to minimize the rise in body temperature that creates sweat and to deter dehydration (for indoor exercise, a fan can mimic the real wind). Wind greatly enhances evaporative heat loss by allowing a greater percentage of your sweat to evaporate. According to an Acta Physiologica Scandinavica article, sweat that falls to the ground only dehydrates the body – it does not assist in cooling the body.
Part two of this series will discuss the advantages and disadvantages of consuming sports drinks for hydration.
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