water is virtually eveywhere, from soil moisture and ice caps, to the cells inside our own bodies. depending on factors like location, fat index, age, and sex, the average human is between 55-60% water. at birth, human babies are even wetter.
being 75% water, they are swimmingly similar to fish. but their water composition drops to 65%by their first birthday. so what role does water play in our bodies, and how much do we actually need to drinkto stay healthy? the h20 in our bodies works to cushionand lubricate joints, regulate temperature, and to nourish the brain and spinal cord. water isn't only in our blood. an adult's brain and heart are almostthree quarters water.
that's roughly equivalent to the amountof moisture in a banana. lungs are more similar to an apple at 83%. and even seemingly dry human bonesare 31% water. if we are essentially made of water, and surrounded by water, why do we still need to drink so much? well, each day we lose two to three litersthrough our sweat, urine, and bowel movements,
and even just from breathing. while these functions are essential to our survival, we need to compensate for the fluid loss. maintaining a balanced water levelis essential to avoid dehydration or over-hydration, both of which can have devastatingeffects on overall health. at first detection of low water levels, sensory receptors in the brain's hypothalamus signal the release of antidiuretic hormone.
when it reached the kidneys, it creates aquaporins, special channels that enable bloodto absorb and retain more water, leading to concentrated, dark urine. increased dehydration can causenotable drops in energy, mood, skin moisture, and blood pressure, as well as signs of cognitive impairment. a dehydrated brain works harder to accomplish the same amount
as a normal brain, and it even temporarily shrinksbecause of its lack of water. over-hydration, or hyponatremia, is usually caused by overconsumptionof water in a short amount of time. athletes are often the victims of over-hydration because of complications in regulating water levels in extreme physical conditions. whereas the dehydrated brain ampsup the production of antidiuretic hormone, the over-hydrated brain slows,or even stops, releasing it into the blood.
sodium electrolytes in the bodybecome diluted, causing cells to swell. in severe cases, the kidneys can't keep up with the resulting volumes of dilute urine. water intoxication then occurs, possibly causing headache, vomiting, and, in rare instances, seizuresor death. but that's a pretty extreme situation.
on a normal, day-to-day basis, maintaining a well-hydrated systemis easy to manage for those of us fortunate enough to have access to clean drinking water. for a long time, conventional wisdom saidthat we should drink eight glasses a day. that estimate has since been fine-tuned. now, the consensus is that the amountof water we need to imbibe depends largely on our weightand environment. the recommended daily intake varies frombetween 2.5-3.7 liters of water for men, and about 2-2.7 liters for women,
a range that is pushed up or down if we are healthy, active, old, or overheating. while water is the healthiest hydrator, other beverages, even those with caffeine like coffee or tea, replenish fluids as well. and water within food makes up about a fifth of our daily h20 intake.
fruits and vegetables like strawberries, cucumbers, and even broccoli are over 90% water, and can supplement liquid intake whileproviding valuable nutrients and fiber. drinking well might also have variouslong-term benefits. studies have shown that optimal hydrationcan lower the chance of stroke, help manage diabetes, and potentially reduce the riskof certain types of cancer. no matter what, getting the right amountof liquid makes a world of difference
in how you'll feel, think, and function day to day.