The human body comprises around 60% water.
It’s commonly recommended that you drink eight 8-ounce (237-mL) glasses of water per day (the 8×8 rule).
Although there’s little science behind this specific rule, staying hydrated is important.
Your brain is strongly influenced by your hydration status.
Studies show that even mild dehydration, such as the loss of 1–3% of body weight, can impair many aspects of brain function.
In a study in young women, researchers found that fluid loss of 1.4% after exercise impaired both mood and concentration. It also increased the frequency of headaches.
Many members of this same research team conducted a similar study in young men. They found that fluid loss of 1.6% was detrimental to working memory and increased feelings of anxiety and fatigue.
Constipation is a common problem that’s characterised by infrequent bowel movements and difficulty passing stool.
Increasing fluid intake is often recommended as a part of the treatment protocol, and there’s some evidence to back this up.
Low water consumption appears to be a risk factor for constipation in both younger and older individuals. Increasing hydration may help decrease constipation.
Mineral water may be a particularly beneficial beverage for those with constipation.
Studies have shown that mineral water that’s rich in magnesium and sodium improves bowel movement frequency and consistency in people with constipation.
If you don’t stay hydrated, your physical performance can suffer. This is particularly important during intense exercise or high heat.
Dehydration can have a noticeable effect if you lose as little as 2% of your body’s water content. However, it isn’t uncommon for athletes to lose as much as 6–10% of their water weight via sweat.
This can lead to altered body temperature control, reduced motivation, and increased fatigue. It can also make exercise feel much more difficult, both physically and mentally.
Optimal hydration has been shown to prevent this from happening, and it may even reduce the oxidative stress that occurs during high intensity exercise. This isn’t surprising when you consider that muscle is about 80% water.
If you exercise intensely and tend to sweat, staying hydrated can help you perform at your absolute best.