Hydration Facts: Understanding Your Fluid Needs & How to Stay Hydrated

By Melissa Halas, MA, RDN, CDE

Use these guidelines to understand your daily fluid needs and to learn key hydration facts for optimal health and performance.

Clients constantly ask, “how much water should I drink per day?” Unfortunately, the answer is less than concrete. People’s needs vary based on their physical environment, exercise routines, sweat habits, food intake, weight, and more. So, it’s best to focus on the body’s tell-tale hydration signs to feel confident about meeting your needs.

Factors that Impact Hydration Needs

There are numerous factors that can influence your hydration needs. Two of the top elements are weight and your exercise routine.

1. Weight

For those who enjoy a more quantitative approach to hydration—weigh yourself before and after exercise to assess your fluid losses. Make sure to do this with minimal clothing since sweat in your clothing can falsely report your weigh-in after exercise.

Then, consume 16-24oz of water for every pound lost once your workout is complete. To improve your fluid absorption, be sure to sip and not chug! In this case, slow and steady really does win the race. (1)

2. Physical Activity and Sweat Habits

During exercise, the body loses a combination of fluid and critical nutrients such as sodium, potassium, and chloride. These electrolytes are essential for fluid balance, ultimately impacting the body’s ability to rehydrate effectively.

But the number of electrolytes needed is dependent on your sweat habits. If you are a “salty sweater,” where you notice a granular residue on your skin or ring marks on your clothing, consider increasing your electrolyte consumption to avoid dehydration.

How Much Water Do Athlete’s Need Each Day?

While this is not an end-all-be-all factor for hydration, it provides a helpful guideline to get started. So, calculate your hydration needs using the steps below.

1. Convert your body weight from pounds to kilograms by diving by 2.2.

2. Multiply your weight in kilograms by 30.

This number is your daily recommended fluid intake in millimeters. (2) However, remember that your habits can increase based on exercise, sweat loss, and your environment.

Fluid Needs Based on Exercise Time and Temperature

• If your workout is under an hour, sticking to water is recommended.

  • During moderate to high-intensity physical activity, it’s recommended to consume approximately 15-30oz of fluid per hour. To make it simple, a big gulp of water ranges between 1-2oz.

• If your sweat-sesh ranges between 60-90 minutes or occurs in a hot and humid environment, water can’t work alone. In this case, add an electrolyte beverage or tablet to help replenish your stores.

For a more individualized hydration approach, consult with a registered dietitian.

Easy Ways to Stay Hydrated

When distracted by the hustle and bustle of the workday, it’s easy to let hydration habits fall by the wayside. Despite your best efforts, your work environment may not be conducive to your health goals. However, allowing your fluid intake to fall short can decrease concentration, cognitive function, energy, and overall work performance. So, check out these easy ways to reach your hydration needs even on the busiest of days.

1. Carry a BPA-Free Water Bottle.

Whether you park it on your desk or toss it in your bag for all-day errands, keeping a water bottle available is a must. Based on your calculated needs, determine how many times you should aim to refill your bottle. Then, be sure to evenly distribute your daily intake to better your overall fluid absorption.

Otherwise, chugging your water will have you ducking out of work meetings or important functions for multiple trips to the bathroom. So, help improve productivity in more ways than one by focusing on consistency rather than speed.

2. Keep Your Drinks Interesting.

Give your beverage an added flare by adding fresh fruit, vegetables, a splash of juice, or herbs. Feel free to also enjoy herbal teas or sparkling water to help improve your intake habits.

3. Take water breaks!

Set a reminder on your phone, laptop, or computer to rehydrate! It’s also a good opportunity to stretch your legs to break up sedentary time. This momentary distraction can help clear your mind while promoting positive habits. If stepping away seems near impossible, simply stand up at your desk! However, a little self-care can go a long way to reaching your health potential.

4. Choose High-Water Content Foods.

Fluids and vegetables are abundant in water. Choices such as cucumber, tomato, celery, watermelon, apples, and peaches are water-filled ways to help hydrate your day. In fact, previous research shows that 20% to 25% of total fluid intake comes from food consumption. So, yet another reason to eat 5-9 servings of fruit and vegetables a day!

5. Enjoy a Tea or Coffee.

As if there weren’t enough reasons to appreciate your morning cup. But, for those who like to customize their brews with all the fixings such as creamers or sweeteners—beware of added calories. Also, be mindful of caffeine intake, with the upper limit being approximately 400mg per day.

Next time you’re looking for hydration facts, come back to these key tips. Knowing your daily fluid needs and staying hydrated for both the work week and for physical activity can help you thrive and feel your best. Plus, your body will thank you!

References:

1. Popkin BM, D'Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010 Aug;68(8):439-58. doi: 10.1111/j.1753-4887.2010.00304.x. PMID: 20646222; PMCID: PMC2908954.

2. Bossingham MJ, Carnell NS, Campbell WW. Water balance, hydration status, and fat-free mass hydration in younger and older adults. Am J Clin Nutr. 2005 Jun;81(6):1342-50. doi: 10.1093/ajcn/81.6.1342. PMID: 15941885; PMCID: PMC2495085.