How Much Water Should You Be Drinking When Exercising?

Whether you’re an elite athlete or a fitness enthusiast, drinking enough water during workout is essential.

Staying hydrated and drinking plenty of water during exercise is incredibly important because your body needs enough fluid before and after exercise, especially first thing in the morning when your body is partially hydrated from not having consumed any fluids throughout the night. But how do you know when you’ve had enough?

How much water should you be drinking when exercising? Not only does research show people who drink more water consume fewer calories, but H2O is also an essential pre-workout beverage.

Whether you need to drink water during workout depends on a number of factors.

Firstly, how long you’re exercising for, how intense your workout is and the air temperature at which you’re working out as each of these factors will affect how much fluid you’re losing through sweat.

So it’s usually recommended to have small to moderate amounts of fluid during a workout, to keep you performing at your peak without hampering your routine and minimize the need to replace so much fluid when you’re done working out.

When you work out, you’re more likely to lose water, both through your breath and through sweat. That’s because water helps your body to exercise efficiently. Not only it lubricates your entire body, but it is also a vital part of the many chemical reactions in the body.

If these reactions slow down then tissues heal slower, muscle recovery becomes slower and the body won’t function at 100% efficiency.

Why Is Hydration Important?

Around 70% of human body is made of water. It’s vital for every chemical reaction in the body. 

Our body needs around 2-3 liters of water a day to transport nutrients, help with digestions, to carry out waste and toxins, and also to support brain function for mood, energy and concentration. 

You lose water and body salts – mostly sodium and chloride – through urine but also when it evaporates as sweat. Even more fluids are lost when you work out, and water losses of only 1-2% of your body weight can impair performance by around 10-20%.

To better understand how you need to deal with thirst during workout, you first need to consider how water can impact your athletic performance. When you start feeling thirsty between your workout sessions, you’re probably a little hydrated already.

Because water makes up 75% of all muscle tissues and about 10% of fatty tissues, the onset of dehydration, even at minimal levels, can have a significant impact on your overall performance. Beyond moderate dehydration, things can get really worse.

Good hydration is important not only for your overall health but also for performance in sport. Many people tend to underestimate their fluid requirements and are constantly dehydrated. When you’re well hydrated, the heart does not have to work as hard to pump blood to the body, and oxygen and nutrients can be transported more efficiently to the muscles whilst working out.

This means it is a lot easier to exercise hard when you are hydrated well and maintain this level of hydration as you work out.

How Much Water Do You Need?

We all lose fluids at different rates depending on our levels of exertion, but as a general guide, always start any workout session well hydrated. But how much water should you drink before, during and after a workout?

How much water you need varies greatly from person to person. There’s a plethora of factors that can determine your hydration needs – including your conditioning level, nutrition, climate and the specific workout.

When working out, it is generally recommended that you consume 15 to 20 ounces of water 1 to 2 hours before starting a workout, as this gives enough time to excrete any excess fluid.

Fifteen minutes before you start, you should drink another 8 to 10 ounces and then continue to drink another 8 ounces for every 15 minutes of physical activity if possible. You may need to drink more if you’re sweating too much, especially if you’re exercising outdoors in very hot weather.

How Should You Hydrate Your Body?

For the best hydration possible, it is recommended that you weigh yourself before and after any type of exercise. For every pound you lost, replace it with 16 to 20 ounces of fluid. If you are losing weight, it is likely that you need to drink more to maintain hydration. It’s important to remember that hydration needs to be maintained daily and not just when you are working out.

Deciding how much to sip in the middle of a sweat session is a little more subjective. If you’re in the middle of a particularly intense workout and feel that you can’t go without a sip of water, by all means, you should take some.

Just know that your preparation for the workout extends beyond eating well and mobilizing. You also need to factor in the temperature of your workout environment. If the temperature isn’t bearable, reaching for the water is still tactic.

Many people use sports drinks during a workout but that’s generally not necessary unless you’re working out for an extended period of time. After 90 minutes of moderate exercise, water is no longer enough.

At this point, your glycogen stores are mere fumes, so you’ll need to start sipping electrolyte-rich sports drinks. Commercial sports drinks are designed to offer you a combination of the fluids and salt you lose during exercise and they come with a variety of descriptions. Managing your minerals is even more important if you’re an endurance athlete.

Drinking Too Much Water

Drinking too much water without replacing electrolytes can cause a condition called hyponatremia. With hyponatremia, the blood becomes excessively diluted from too much water and sodium levels drop to dangerously low levels. This can lead to nausea, headaches, fatigue, seizures, organ failure, and in extreme cases, coma and even death.

However, you’d have to drink like gallons of water to suffer hyponatremia – enough to gain weight over the course of a workout which is rare. If you’re tackling long-distance runs, make sure you have a proper hydration strategy in place.

Paul J

Last Updated on August 20, 2021