The Question:
How much water should you actually drink per day? It is common knowledge that hydration is extremely important to health and exercise. The human body is made up of around 60% water, and it is extremely important for helping remove toxic metabolic byproducts with the help of namely your kidneys and liver. Water also helps with regulating bowel movements and increasing muscles growth. This is good to know, but how much water is the right amount? This is a question that we have been asked a lot recently, and I started looking into the research. We have all heard the common 8 glasses per day but recently there has been an abundance of YouTubers telling us to drink a gallon of water a day. So what is the real amount of water you should aim for? Let us tell you below!!
The Science Behind Daily Water Needs:
Throughout the research, the amount of water is usually shown in glasses, ounces, liters, and gallons. Seeing as this can get pretty confusing, I am going to show all of the conversions to you up front, and always use glasses of water to equalize the results as we discuss.
8 ounces = 1 glass
4 glasses = 1 liter
3.8 liters = 1 gallon
In the journal of Nutrition Reviews, Dr. Sawka found that while human’s need for water consumption can vary considerably given exercise and heat stressors, the vast majority of men need around 3.7 L (15 glasses) and the majority of women need around 2.7 L (11 glasses) of water per day. So while 8 glasses per day has been a staple for decades, it seems that the numbers we actually need is much higher.
The Institute of Medicine also compiled many research studies into a list called the dietary reference intake. This agrees with Dr. Sawka’s finding for adult males 14 years and older (15 glasses) and adult females 14 years and older (11 glasses). It also talks about children 1-3 (5 glasses) and 4-8 (7 glasses). Pubescent males need around 13 glasses, and pubescent females around 9 glasses.
The Science Behind Water Needs While Working Out:
The American Council on Exercise reviewed 16 studies and published a great list of recommendations regarding how much water is required while exercising. Ironsnack Fitness reviewed their recommendations and summarized those with valid evidence below.
- Drink 2-3 glasses of water within 2 hours before working out
- Drink 1 glass of water 30 minutes prior to working out
- Drink 1 glass of water for every 20 minutes of workout
- Drink another glass after you finished working out
- If you are working out for longer than an hour it is important to replenish your carbs and electrolytes with some sports drink
Thoughts From a Triathlete:
As a long distance triathlete hydration is extremely important to me. This next section is from personal experience and words from coaches and Ironman finishers. During long distance triathlons, I always have multiple bottles of water handy during my bike and run. Along with a bottle that I sip on after my swim while changing and getting ready for the bike. Drinking water during the transition is not necessarily a recommended action, because it wastes some time from the actual race. That being said, I know that when I played college tennis, the minute I would get dehydrated even slightly my game play would drop tremendously. Because of this I usually opt to take a few minutes extra for water breaks in transition, and hope that it takes time that could have been wasted if I let myself get dehydrated. I usually will drink one bottle of straight water, and multiple bottle of a sports drink during both the bike and runs depending on length. For beginner triathletes that usually ends up being a bottle mixed of water and gatorade. There is a company called Infinit, that now will spend 30 min talking with you on the phone and completely customize a sports drink to your height, weight, and racing style. That is what I have been using and I am very excited about it. I also found this water bottle which I love because it’s easy to clean and lets me keep track of how much I am drinking. Regardless of what you use, make sure to stay well hydrated! I have seen people who have messed up their hydration, and it ruins the entire race for them. Follow the simple guides we have provided here and hydration should never be a problem for you. If you have any questions, please feel free to comment below or contact us.
Resources For How Much Water To Drink:
Human Water Needs
https://academic.oup.com/nutritionreviews/article-abstract/63/suppl_1/S30/1927756/Human-Water-Needs
Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Total Water and Macronutrients
Healthy Hydration
https://www.acefitness.org/acefit/healthy_living_fit_facts_content.aspx?itemid=173