Your skin does this weird ‘tent-ing’ thing
Pinch the back of your hand and hold for a few seconds; when you let go, your skin should snap back into position pretty quickly. If it’s slow to return to normal, take that as one of the signs of dehydration. “Skin turgor—a measure of skin elasticity—begins to decrease with a fluid loss of about 5 percent, which is considered mild dehydration,” explains Chris G. Adigun, MD, a board-certified dermatologist in Chapel Hill, North Carolina. With more moderate or severe dehydration, the pinched-up skin will remain “tented” in place. You know why else you should stay hydrated? To help you look younger. “Especially as we age, the visible appearance of the skin of the face improves with superb hydration,” adds Adigun. Here are some more health benefits of drinking enough water during the day.
You have a crappy workout
Dehydration reduces blood pressure and makes the heart work harder, which impacts how much you can push yourself, explains Larson. “Even a 2 to 3 percent fluid loss affects your ability to get a good workout,” she says; “and more than 5 percent dehydration decreases exercise capacity by about 30 percent.” Here’s how much water you should aim to drink a day.
You drive like you’re drunk
You pee before you hit the road and barely sip your bottle of water en route, all in the name of avoiding pit stops. We get it. But according to research published in Physiology and Behavior, driving while dehydrated may be just as dangerous as getting behind the wheel intoxicated, in terms of how many mistakes you could make on the road. British researchers had study participants take two-hour drives (using a simulator): when they were well-hydrated, there were 47 driving errors; dehydrated, slips-up—including lane drifting and late braking—more than doubled to 101. Dehydration causes fatigue and affects our cognitive abilities, like clear thinking and reaction time, says Larson.