How much water do I need to drink?
You’ve likely heard you should aim to drink eight glasses of water a day, and maybe you’ve seen people lug huge jugs of water around the gym. Perhaps your officemate keeps a pitcher of water on her desk and makes a point to drink it all each day. Which of these is right for you? Or do you need something different?
The answer, well, it depends on a few factors, because every person’s water needs are a bit different—and your individual water needs could change from one day to the next.
How do my hydration needs compare to yours?
Hydration needs vary from person to person, but men typically require more water than women. The average man needs about 12 cups (3 liters) a day while the average woman needs around 9 cups (2.2 liters) per day. If you’re feeling overwhelmed by those amounts, remember that plenty of the food we eat hydrates us too.
Some of the most hydrating foods include watermelon, cucumber, strawberries, and lettuce. But you’ll still need to sip on something to truly quench your thirst, and generally, water is your best bet. Soft drinks may sound appealing when you’re hot and thirsty, but drinking soft drinks in order to rehydrate has actually been shown to worsen dehydration and increase the potential for kidney damage. Caffeinated beverages, such as coffee, are often said to act as diuretics. While this isn’t entirely true (if you regularly consume coffee, you will develop a tolerance for that amount of caffeine and it will no longer have the same diuretic action), it’s important to realise that caffeinated drinks don’t provide you with the optimum hydration to focus and feel energised the way plain old water does.
Another reason to consider sticking with water? Drinking a little more than 2 cups (500 milliliters) of pure water has been shown to increase your metabolic rate, which is a pretty cool way to increase that burn.
As we get older the human body is better able to conserve water. With age, our sense of thirst becomes less acute too, which makes it easy to become dehydrated without realising. The elderly population is generally more likely to take a variety of medications, some of which can lead to dehydration. And to top things off, because some elderly people experience mobility problems, it's not only more challenging to get a glass of water, but also significantly more difficult to use the restroom regularly.
Infants and children are at even greater risk of dehydration, as they’re the demographic most likely to experience vomiting and diarrhea—both of which are seriously dehydrating. Young children may also simply lack the ability to communicate their thirst or get themselves something to drink.
This won’t come as a shock, but when it’s hot out, we sweat more—meaning we need to replace more fluids. High humidity is also a factor, as it prevents sweat from evaporating and cooling efficiently.
In addition to acute issues such as vomiting and diarrhea, other illnesses including uncontrolled or untreated diabetes, kidney disease, or even a cold or sore throat can increase your risk for dehydration.
Whether you participate in a sport or fitness event or work outdoors, your risk of becoming dehydrated increases with any vigorous activity.