Athletes, people trying to lose weight, and even the general public are instructed to ensure high levels of hydration through out the day. Ingesting non-diuretic and non-damaging (ie alcohol) fluids help the body to maintain normal function of the organs, encourages homeostasis within all systems of the body, and keep the physiological stress of the tissues at a lower level. Fluids provide a sensation of fullness (one of the reasons they benefit weight loss), and also encourage mental alertness. People who struggle to get through the day (headaches, hunger pangs, fatigue) are often alleviated by increasing the intake of fluids. Thirst has been said to be a poor indicator of hydration because by the time the thirst mechanism is activated, it is too late. Urine color has shown to be a better indicator where lighter urine color (lemonade-like) is ideal versus a darker color (apple juice color). Note that some vitamins and foods will have an effect on color regardless of exertion and fluid intake.
Hydration’s Effect On Performance
Researchers from the U.S. Army Research Institute of Environmental Medicine reveal interesting findings relating to hydration, and performance in the heat as well as the cold. Common knowledge and personal experience has shown many people that activities performed in the heat are harder to accomplish than when the temperature is cooler. This experiment confirms this observation but also notes that when all other factors were held constant, a drop in temperature alone did not have a negative effect on performance. The bulk of the study examined the body’s response to hot, cold, fluid retention, and performance in each of those environments.
Not surprisingly, the researchers found that as it got hotter and the more dehydration set in, there was a worsening of performance. The subjects felt as though they were performing at the same level, but they were actually not able to produce nearly as much as power as they had previously done. Fluid absorption and intake will help prevent weight loss and the loss of essential substances of the body. Losing as little as 3% body weight (which is often and easily done by marathoners) has a dramatic effect on performance when the activity is being done in the heat. This research is important to athletes who compete in the heat, as well as people who are physically active while outdoors. Performance in this study was sport related, but it shows that the body is affected so it should serve as fair warning to construction workers, gardeners, soldiers, lifeguards, and any other individual who must be physically active and spends time in the heat. The hotter it got, the more markedly the negative effects were.
While colder temperatures had less of an effect on performance based on the “fluid status” of the person, there seemed to be a way to keep fluids available for use even though the individual could not consume them. Participants consumed a glycerol substance and were found to be hyper-hydrated after they were exposed to cold air temperature. The glycerol is a sweet syrup like substance that reacts in such a manner that allows the body to “better preserve the extravascular fluid volume, accounting for the improved TBW (total body water), compared with water alone. This extravascular ‘reserve’ could later be called on during exercise or heat stress, when hydration becomes important to performance and thermoregulation,” the paper noted. The next step will be to examine how this finding will translate to performance while under these cold temperatures.
We see that the body needs proper fluid balance in order to perform at its peak. Dehydration will have negative effects on performance, especially as it get warmer. Dehydration will have marginal affect on performance in the cold, but it is possible to increase the level of available fluid by ingesting a glycerol solution. As with anything ingested, fluid consumption should not be done to either extreme. Find balance, and find yourself performing better.