Scientific research isn’t always your friend. The evidence can be conflicting, backed by financially interested parties, or simply not applicable to your particular brand of sport. You’re the athlete, and if you listen, your body will likely tell you what’s up. However, there are some trusted schools of thought behind hydration and rehydration.
In researching this article, I found a sweet chart depicting urine color as it corresponds to hydration levels. A nice, light yellow for a well-hydrated body gradually increasing to something the color of pea soup as dehydration sets in. (Pretty sure the pea-soup fella has severely compromised kidney function and should go to the emergency room immediately.) Unless you’re taking high levels of Riboflavin (vitamin B2, which causes urine to fluoresce), this color method is a good indicator of fluid levels. You can also look to the amount of urine output as a guide. Most individuals need to go every couple hours with proper fluid intake, rounding out to a good seven or eight trips to the restroom daily.
My method is to drink water first thing when I wake up. As the day goes on, I drink more. I divide my body weight (in pounds) by two, and then try to drink that many ounces of water. I weigh 130 pounds, so that’s 65 ounces of water, though I usually make it to about 80.
Now we need to factor in sweating. This is where things get complicated—where everyone goes to their own corners to play.
As you exercise, your body temperature increases, and as your body temperature increases, you sweat to cool yourself down; this is common knowledge. But sometimes we forget the basics. Sometimes nutritionists like myself will nearly pass out from heat exhaustion on a quick 5k and wonder why we aren’t breaking a sweat. Sometimes we get so used to being the girl who never goes anywhere without 40oz of water that we don’t notice when we’ve stopped being the girl who actually drinks that water.
Fluid levels and electrolyte (salt) balance on the interior and exterior of cells are important for your body to function properly. When this balance isn’t actualized, your body gives you clues. If I go on a run while I’m dehydrated, I don’t sweat. If I don’t sweat while I run, I’m soon walking, red-faced and weak. Dehydration can also cause muscle fatigue and a loss of coordination.
But there’s also such a thing as overhydration. Consuming too much water or other fluids as you work causes your cells to swell, meaning there’s too much water in them in relation to electrolytes. Your body can more or less adapt to this situation and will alert you via muscle soreness, dizziness, or an upset stomach. In severe cases, however, your brain may actually swell. Because your brain lives within a confined space, this swelling can affect blood and oxygen flow to the brain and result in actual brain damage.
The American College of Sports Medicine (ACSM) advocates weighing yourself before and after exercise and rehydrating to keep sweating-induced weight loss at under 2% of your body weight (for me, roughly two pounds). I don’t own a scale, so I refer to my own knowledge of how much water I’ve had leading up to exercise and the color of my urine both before and after.
My seven-year-old plays soccer. She runs with her arms tucked up near her torso like a tiny T. rex. She doesn’t sweat. Aside from the T. rex stance, her little soccer buddies are in the same boat. Yet some of their parents provide them with heavily sweetened sports drinks. Do they need these? And, even if you’re a more accomplished athlete than these kids, do you?
Con: Sugar (nutrient-free calories) content. One benefit of exercise is that it uses up excess calories, helping you maintain a healthy weight. Many sports drinks, however, have an amount of sugar rivaling that of soda.
Pro: They also contain electrolytes such as sodium, chloride, and potassium, which we’ve discussed as important for maintaining proper fluid balance in the cells and therefore proper bodily function.
The fact of the matter, though, is that light exercise, even that spanning an hour or two, or exercise resulting in moderate sweating really isn’t enough for your body to require help maintaining electrolyte balance. It already knows how to do this, and as long as you’ve provided it with adequate water prior to exercise and during (if you’re sweating moderately or simply hot and thirsty), it can handle the more detailed electrolyte work on its own. If you’re participating in endurance activities (marathons, high-intensity bike rides up the Pacific Highway, hours-long hikes in knee-deep powder searching for perfectly untouched lines), then a drink providing you with carbohydrate content (the con just became a pro) and electrolyte support can be useful. Some drinks, often marketed as recovery drinks, also include protein, which help replace muscles’ energy stores (glycogen) as well as aid the body in repairing and synthesizing new muscle.
You can make this as complicated as you want. You can worry about how soon before, how soon after, what ratio of X ingredient to Y ingredient, etc., but isn’t life hard enough already? I choose to make it simple. Water is usually sufficient; just remember to drink it. Hydration and recovery drinks can have benefits in the body under certain circumstances, but they’re often overused and an unnecessary cost. Listen to your body; most of us don’t give ours the credit it deserves.