Good Ol’ Summertime Hydration Includes Drinking Coffee

Temperatures climb. Humidity increases. And so does outdoor activity for many of us. So, paying attention to drinking enough fluids and staying well hydrated is important. After all, our body is about 60 percent water, and fluid is the key for maintaining normal physical and cognitive function. Even mild dehydration may cause fatigue, headache, mood change, tension and decreased memory.

Now, here comes the good news. Coffee counts! Yes, moderate coffee consumption – including caffeinated coffee – contributes to daily fluid intake needs. And what is considered “moderate” when drinking this world-wide favorite beverage? According to most authorities, it’s 3 to 5 (8-oz.) cups in a day.

What the Experts Say

After repeatedly hearing advice to avoid caffeinated beverages because they cause dehydration, it may be hard to believe that there’s widespread consensus stating the opposite.

  • In 2004, the Institute of Medicine said that all beverages – including caffeinated beverages – are hydrating.
  • The International Life Sciences Institute issued a consensus statement in 2006 recommending consuming a variety of caffeinated and non-caffeinated beverages to meet the body’s fluid requirements.
  • And the U. S. Beverage Guidance Panel reviewed the scientific evidence on coffee and hydration and concluded in 2006 that consuming up to 500 mg of caffeine in a day (about 5 regular cups of coffee) does not cause dehydration.
  • More recent studies continue to support these statements.

So What About Caffeine, Exercise & Heat?
It’s the same story!

  • According to research, the amount of caffeine found in about 3 regular cups of coffee (300 mg) has no significant effect on overall fluid balance during exercise. It induces a mild, short-term diuretic effect, similar to that of water.
  • Also, there is no evidence that caffeine is detrimental in hot climates during exercise when fluid losses are the greatest.

Daily Fluid Requirements
Your fluid needs are quite individual and widely vary based on activity level, climate and health. Here are a few points to keep in mind:

  • Think about drinking enough fluid so that you are rarely thirsty.
  • Choose no calorie or low calorie beverages most of the time, remembering to hydrate at and between meals, and before, during and after exercise.
  • 8, 8-oz. glasses of fluid a day is a good place to start. This totals less than most health authorities’ recommendations (about 9 to 13 cups, higher amounts for men). But it isn’t too far off when water from food in a healthy, balanced diet is included.
  • Calorie-free, inexpensive water always is a great fluid choice! For variety, remember that coffee, tea, milk, juice, are mostly water, too. Black coffee is 95% water and only has about 10 calories in an 8-ounce cup.
  • Food contributes about 20% of the fluid in your diet. Many fruits and vegetables, such as melons, citrus, berries, squash, spinach and cabbage, are high in water.
  • Additional fluid is required with exercise, in certain environments (heat, humidity, higher altitudes), pregnancy and breastfeeding, and some illnesses. It is possible, though rare, to consume too many fluids, which can cause sickness and potentially be life-threatening. Consult a doctor or registered dietitian nutritionist for individual recommendations.

Tasty Summer Hydration
Summertime is ideal for sipping cold, refreshing iced coffee – at home. Yes, you can simply brew coffee your usual way and let it cool before pouring over ice, yielding a bold, bright and refreshing drink.

But many prefer cold-brew coffee for making iced coffee because of its smooth, more subtle flavor. To make cold-brew coffee, here are the super-simple steps.

Easy Cold-Brew Coffee at Home​

  1. Combine ground coffee and cool water in large container (about 1 cup coffee for every quart of water; I used 5 cups or 12 oz. ground coffee and 5 quarts water)
  2. Cover and let sit at room temperature about 24 hours (less if desired)
  3. Filter through cheesecloth-lined strainer or coffee filter… then refrigerate this liquid gold
  4. Serve over coffee ice cubes (I freeze leftover coffee in ice cube trays so the iced coffee doesn’t become diluted) or ice
  5. Stir in as desired: milk, almond or soy milk, cream, flavored creamer, condensed milk, simple syrup (heat and combine equal parts water and sugar; keep in refrigerator) or a pinch of Kosher salt

Note: Store cold-brew coffee in refrigerator, up to a week.


Popkin B.M. et al. (2006) A new proposed guidance system for beverage consumption in the United States. Am. J. Clin. Nutr, 83:529-542.
Silva A.M. et al. (2013) Total body water and its compartments are not affected by ingesting a moderate dose of caffeine in healthy young adult males. Appl. Physiol. Nutr. Metab, 38:6.
Kolasa K.M. et al. (2009). Hydration and health promotion. Nutr Today, 44:190-203.
Ganio M.S. et al. (2007). Evidence-based approach to lingering hydration questions. Clin Sports Med 26, 12-16.
Goldstein E.R. et al. (2010) Caffeine enhances upper body strength in resistance trained athletes. J. Int Soc Sports Nut, 7:5.
Armstrong L.E. (2002). Caffeine, body fluid-electrolyte balance, and exercise performance. International Journal of Sport Nutrition and Exercise Metabolism 12, 205-222.
Killer S. C. et al (2014) No Evidence of Dehydration with Moderate Daily Coffee Intake: A Counterbalanced Cross-Over Study in a Free-Living Population. PLoS ONE, 9(1): e84154.
Ganio M.S. et al (2009). Effect of caffeine on sport-specific endurance performance: a systematic review. Journal of Strength and Conditioning Research. Volume 23; 315-324.

Beth Witherspoon, MPH, RDN, has a passion for communicating culinary and nutrition information. She is a registered dietitian/nutritionist who consults with Community Coffee Company to help communicate the flavor and health benefits of coffee.