Hydration is simple. Feel thirsty? Drink something. Despite this simplicity, there’s an ocean of misleading information out there that leaves hard working truck drivers confused. CDL drivers face numerous dangers in the summer heat, and staying hydrated must remain top-of-mind. Check out the following myths about hydration from this Month’s Melton Safety Topic Guide:
1. Myth: Drink eight glasses of water a day.
Truth: You do need a healthy dose of hydration daily, but how much is an individual thing. “The eight glasses a day is totally arbitrary,” says Susan Yeargin, Ph.D., assistant professor of athletic training at the University of South Carolina. “Everybody, especially athletes and those working in excessive heat, has different needs.” The Institute of Medicine guidelines are more specific, recommending 91 ounces per day for women and 120 for men. But the institute notes that “the vast majority of healthy people adequately meet their hydration needs by letting thirst be their guide.”
2. Myth: Caffeine dehydrates you.
Truth: While caffeine provides a performance-boosting edge, it also acts as a diuretic, right? Not exactly. “Recent research shows that caffeine doses between 250 and 300 milligrams—about two cups of coffee—will minimally increase urine output for about three hours after consuming it,” says Yeargin, “But the research also shows that exercise seems to negate those effects. If you exercise within one to two hours of drinking coffee, you don’t pee more.” Most likely, during physical exertion, blood flow shifts toward your muscles and away from your kidneys, so urine output isn’t affected, Yeargin explains. In addition, if you always have a latte in the morning or a diet soda at lunch, your body is acclimated to the caffeine, so its effect, on both your physiology and work performance, is minimal.
3. Myth: Pure water is best for hydration.
Truth: Although water is a great way to hydrate, it may not be the best choice in all situations. For an easy, hour-long tarp job on a coolish day, sipping water is fine. But if you’re working outside 1+ hours on an August summer morning and are a salty sweater (you have white salt streaks on your face or clothes), you need to ingest some sodium as well. “Salt helps you retain water,” says Yeargin. “You’re less likely to pee it out.” A sports drink, such as Gatorade, and water enhanced with electrolytes, like Nuun, are good options. “There’s no way to ‘preload’ with sodium to negate sodium loss,” says Yeargin. “You just pee out anything you don’t use.”
4. Myth: You can’t drink too much.
Truth: “You absolutely can drink too much,” says Casa, “and it can be deadly.” Too much water can cause symptomatic hyponatremia, a condition where the sodium levels in the blood become dangerously low. Although Casa estimates that fewer than one percent of individuals develop symptomatic hyponatremia. “For the industrial athlete, the best way to prevent hyponatremia is to listen to your thirst,” says Casa.
5. Myth: Drinking lots of water is a good way to “detox.”
Truth: “There is no evidence that excess water makes your body more clean,” says Dr. Stanley Goldfarb, M.D., a professor of medicine in the Renal, Electrolyte, and Hypertension Division at the University of Pennsylvania’s Perelman School of Medicine. “If anything, drinking too much water can slightly impair the ability of the kidneys to filter blood.” He adds that the only people who should drink more water with a focus on their kidneys are those who have had kidney stones.
6. Myth: Staying hydrated eliminates your risk of heat stroke.
Truth: Heat stroke is a life-threatening condition where your body temperature rises above 104°F. Dehydration can make you more prone to it. “People who are dehydrated are hotter,” says Casa. In fact, in a study published in the Journal of Athletic Training, Casa determined that for every one percent of body mass lost through sweat, your body temperature increases by half a degree, “which makes hydration hugely important for preventing heat stroke,” he says. But there are still a number of other factors that play a role. Body size, exercise intensity, fitness level, and age as well as humidity and air temperature can affect who does or doesn’t develop heat stroke, says Casa. Certainly staying hydrated is a good call and can reduce your risk, but paying attention to the whole picture is a better predictor.