Why must I drink lots of water?

September 8, 2012

Q: I have read that it’s important for people who work out to drink enough water, but nobody has ever explained to me exactly why I have to choke down 8-10 glasses daily if I’m not thirsty. Also, I have found that if I try to drink more I end up having to get up during the middle of the night to use the bathroom, and I’d rather sleep soundly. So why is it so important if I seem to do fine without it?

A: Everyone knows you are what you eat, but I think a lot of people underestimate the importance of water. Drink enough water and your body will function like a finely tuned machine. Drink too little and your performance will suffer, and you could be at risk for some very serious medical conditions.

Water equals life

The human body can last up to eight weeks without food but can only live three to five days without water. This is mainly because water is needed for every physiological function from breathing air to properly digesting food. It’s also because, unlike food, the body can’t store water, so it must be replenished daily or you’ll have some big problems on your hands. Now obviously, most people will drink enough water to stay alive, but many will underestimate the need for proper hydration while exercising and will suffer heat-related injuries. Don’t let it happen to you - drink 8-10 glasses of water a day, and increase your water intake on days when you are more active or experience abnormally hot weather.

Boost your metabolism and lose weight

There are many different diets out there today, but the one thing they all seem to agree on is that drinking 8-10 glasses of water a day will accelerate weight loss. This is because research has proven that drinking water can kick your metabolism into high gear, help you properly digest food and reduce hunger by making you feel fuller and less likely to snack between meals. In fact, many people confuse hunger with thirst, and drinking enough water can help you control your appetite without the added calories.

Increase results and physical performance

Drinking enough water can boost your performance during workouts by lubricating your joints and helping your muscles recover faster. This is mainly because muscles are made up of about 70-75 percent water, and when you become dehydrated they can’t function properly. Failure to drink enough water can result in painful muscle cramps or spasms, or even strains or tears. It can also cause fatigue and lack of energy and strength, making it difficult to work out or perform at optimum levels.

Promote mental clarity

Most people associate dehydration with a decline in physical performance, but few realize the effect it can have on their mental state. Fatigue, anxiety and stress and are all results of dehydration and can be avoided by drinking enough water. Remember, your brain is made of approximately 70-80 percent water, and if you are dehydrated it won’t function properly.

Look and feel young

Drinking water hydrates skin cells and improves circulation and blood flow, resulting in younger-looking skin. It can also help increase energy and will make you feel great if you drink enough water and stay hydrated.

It’s important to remember that those who work out require more water than those who don’t, so for best results adjust your water intake depending on environmental conditions and activity levels.

  • Chris Antonio is a personal trainer and former world-class weightlifter. He has been lifting for more than 20 years and has trained a wide variety of clients ranging from All-American athletes to the average person trying to get into shape. To send a question to the Ask the Trainer column, email Chris at or check out