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Optimal Hydration For Athletes

Updated: Oct 20

Arguably the biggest factor that can directly impair athletic performance is hydration status — and it's not as simple as just drinking loads of water all day. Let’s talk about the latest evidence when it comes to optimal hydration for athletes. First, we're going to just review the importance of hydration.

Maintaining an optimal hydration status will help:

  • Regulate body temperature (helps cools your body in hot and humid environments)

  • Improve your muscle’s ability to recover

  • Minimize risk for muscle cramps

  • Enhance cognitive performance

  • Support immune function

When it comes to dehydration, if you experience a 2% total weight loss from sweat during exercise; that would be considered significant. This is when impairments in health and performance occur, such as lack of concentration, dizziness, early fatigue, trouble tolerating heat, delayed recovery, muscle cramps, headaches, nausea, abnormal heart rate, and an increase in perceived exertion (meaning you feel much more tired than you actually are).

So a 2% weight loss; what does that look like? Well if you're 180 lbs, that would be 3-4 lbs of weight loss during your session. Now I don't always like to recommend weighing yourself, especially as an athlete, but if you are curious to know how much weight you're losing in the form of sweat during your session, I think it can be a pretty valuable tool. So what are some general indications of dehydration?

You are likely dehydrated if you have two or more of the following markers:

  • Darker urine in the morning

  • Lower waking body weight

  • Greater thirst than usual

Keep in mind, it can take up to 24 hours to recover from a state of dehydration; so don't expect to fully rehydrate a couple hours a big game or training session. Rather you need to evenly distribute fluid intake throughout the day for best results.

How Much Fluid Do You Need?

As always, the answer is: it depends. There's a lot of factors that go into hydration and needs are personal. Three primary factors include: 1) the duration and intensity of activity; 2) the environment, such has heat, humidity, and altitude; and 3) you’re your sweat rate, which varies person to person.

Practical Tips and Guidelines:


  • 2-3 hours before; aim for 16-20 oz. of fluid

  • 15 minutes before; aim for 8 oz. of fluid


  • For sessions < 60 minutes: drink plain water as needed

  • For sessions > 60 minutes: drink 16-32 oz. of water or sports drinks depending on intensity and environment


  • Replace 1.5 x weight loss experienced during exercise

  • Example: Drink 24 oz. of fluid for every pound lost

Daily Needs:

  • Aim for at least half your body weight in ounces

  • Example: 150lb person should have a minimum of 75 oz. per day

Simple Tips To Improve Hydration:

  • Carry a water bottle everywhere you go

  • Aim to have at least 2 cups of water with all meals

  • Begin lunch or dinner with a veggie soup

  • Drink a glass of water first thing when you wake up

  • Steep a a cup of herbal tea in the evening

  • Consider adding more fruits and vegetables that have high water content, such as:

  • Oranges, berries, melons, pineapple, eggplant, zucchini, carrots, cucumbers, and tomatoes

If you are a serious athlete who wants to be precise with fluid needs during exercise, you can take it to the next level by calculating your sweat rate. This may sound intimidating, but it’s not really that difficult at all. Everyone has a slightly different sweat rate, and it could be helpful to know yours if you want to appropriately replace your sweat losses. You can follow the step-by-step guide below if you are curious:

Proper hydration is a cornerstone to overall health. While some days are better than others, most people listen to their bodies and do a decent job at getting in enough fluid throughout the day. However, when you factor in physical activity, your risk for dehydration goes up exponentially! The longer and harder you exercise, the more important it becomes to pay attention to your fluid intake. If you do a little extra planning, you will set yourself up for success. If you are consistent with your water intake throughout the day and are mindful of pre-, during-, and post-exercise hydration; not only will you prevent potential issues, but you will actually improve your performance!


Jack O’Connor, MS, RD

Lead Performance Dietitian, Inc Nutrition

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