Maintaining proper hydration in the summertime is pretty easy. It’s hot outside, so we naturally want to drink more water. Sure, it’s easier to get dehydrated in the summertime because of the heat and increased outdoor activity, but it’s also easier to tell how dehydrated you are. In the wintertime, it’s a bit more difficult to tell how dehydrated you are.
A study done by a group of kinesiology researchers at the University of New Hampshire reported that the body’s thirst response is diminished by up to 40% in cold weather. This happens because when you’re cold the blood vessels in your hands and feet (your extremities) constrict. Your body does this to conserve heat and draw more blood into your core. As a result your hands and feet get uncomfortably cold in the wintertime. This also means your body is a lot less sensitive to knowing how much water you’re storing in it at any given time. You could be dehydrated and not know it. Your body is basically fooling itself into believing it’s well-hydrated and doesn’t have to tell you to drink water. This can be especially dangerous for athletes who don’t feel the same need to hydrate as they would in warmer weather.
Along with fooling your sense of thirst, your body does an even better job of fooling itself. If your body thinks it’s perfectly hydrated, your kidneys will continue to excrete water from your system rather than store it. It’s more difficult to adequately hydrate yourself in the wintertime if you don’t pay close attention to how much water you’re drinking. The current recommendation is the “eight-by-eight rule” – eight ounces of water eight times a day. You’ve probably heard of this rule. You might be surprised to learn that this rule actually has no scientific basis. It’s an arbitrary number, put forward by the 1945 Food and Nutrition Board of the National Academy of Sciences. When they made this recommendation, they cited no clinical studies to back it up. Still, this rule has benefited people for years. It’s an easy-to-remember number. If you try to follow this rule, you’re bringing hydration to the forefront of your mind, and you’ll remember to drink more water throughout the day. Unfortunately, since this guideline isn’t backed up by real clinical studies, there’s no way to know how much water you really should consume in a day. The best recommendation is to listen to your body: it’ll tell you how much water you need to drink. If you’re stuck in cold, wintry Iowa where your body’s thirst sensors are tuned down by 40%, you’re best to just make sure to carry a water bottle around with you all day long. That way you’ll always have water if you need it, and you’ll be carrying a constant reminder to hydrate, hydrate, hydrate. About 60% of your body is composed of water. So do your body a favor and make sure you hydrate all day long, every season of the year.