Updated: Oct 15, 2021
Depending upon age and gender, the human body is made up of about 70% water. On average about 45-50% of body weight in adult females is water. For adult males, body water is about 50-60%, due to more lean mass, on average. As we age, from childhood through adulthood, and gain and lose lean mass, our body water changes.
The brain is about 95% water, blood is about 82% water, and the lungs are about 90% water. Given these numbers, it’s safe to say water is, hands-down, the most critical, nutritious substance we need to consume. Not one supplement, macro, or drug can take the place of the developmental and nutritive benefits of water.
Benefits of Hydration
Aside from staying alive, regularly consuming water throughout the day can help with:
Improved Cognitive and Muscular function: Muscles are about 75% water and the brain is about 95% water. A mere 2% drop in hydration level will affect endurance, speed, agility, reaction time, mental clarity, and thermoregulation.
Improved Circulation: Being properly hydrated means the body can more effectively circulate blood, and thus move oxygen and nutrients into muscles and organs, while also removing waste products.
Blood Pressure Regulation: Through the improved circulation, your heart won’t have to work quite as hard to maintain normal blood pressure during and after exercise.
Reduce Injury Risk: Through exercise, muscle fatigue is inevitable, which can lead to increased injury risk. Properly hydrated muscles resist fatigue and reduce injury risk, to a point.
Improved Thermoregulation: The body regulates heat through sweat, which causes us to lose water. Replacing that water is critical to thermoregulation, which protects us from heat exhaustion, cramps, even heat stroke.
There are a lot of thoughts on this, and the reality is that it varies based on activity, intensity, environment, age, and weight. The gold standard that has been kicked around for a long time is to drink eight cups of water per day. That’s likely plenty for those of us who exercise for an hour, then go about our day in meetings and hanging out at home.
For athletes, especially those who train in more extreme conditions (hot or cold), something closer to 0.5-1oz of water per pound of body weight each day. Plus, keeping an eye on how much weight you lose during practice will help you get a better idea of whether you need to adjust that metric. Typically, you don’t want to lose more than 2% of your body weight during a workout or practice session. Make sure to take regular sips throughout your exercise session, and drink about 24oz of water for each pound of body weight lost during your workout.
Yes, that’s a lot of water, and yes, you will have to pee a lot. It’s a small price to pay for optimal performance. Also, these aren’t hard rules, they’re starting points.
Water should be consumed throughout the day. From first thing in the morning to the evening. Upon waking up, you’ve likely gone about 7-8 hours without any water. While you’re brewing your morning coffee, drink a glass of water. You get extra points if you add a pinch of salt and some lemon juice to get in some electrolytes and kick-start your digestion.
Keep drinking throughout the day with meals and in-between meals. This can really help with hunger if you’re fasting or cutting calories. Around your workouts is the next big area to focus on. We discussed this a bit in the above section. In the evening, try to taper-off drinking water as you get closer to bedtime. Multiple trips to the bathroom in the middle of the night can ruin a good night of sleep. I think one or two trips max is okay.
Hydration requirements, like any other dietary requirement, are highly dependent on the individual, their physical stress, environment, and physiology. We have some metrics for starting points, but it takes a lot of time and experimentation to find what works best for the individual, and in what circumstances.
For most of us, making sure we drink water upon waking, during meals, and around exercise will set us up for success. For athletes, especially those in demanding endurance and power sports, it’s worth investing the time in your hydration, just as you likely do in your nutrition. The two go hand-in-hand. Drink your water!