The harmless H2O which makes up about 60% of the human body, can actually become harmful in some cases. There are lots of health myths surrounding water, which turned it into something similar to a miracle. Water can help you lose weight, make your skin look better, flush out toxins and other such claims are wide spread in health publications.
Perhaps the most important claim, which truly drives some people into drinking more water than they need is the myth saying when you’re thirsty you’re already dehydrated. We start feeling thirsty the amount of solids in blood rises by 2%. Serious symptoms of dehydration appear once blood solids have risen by at least 5% so under normal circumstances thirst is a reliable indicator for water intake.
Sure, it’s not the 8×8 rule that can kill you (8, 8-ounce glasses of water per day). Dilutional hyponatremia also known as water intoxication, occurs when the concentration of sodium in the blood drop below 135 millimoles per liter.
This happens when you drink too much water within a short period of time. Because the kidneys can only flush a limited amount of water, the excess water leaves the blood entering the cells. While brain cells do have the ability to expand (like other cells in our body), there’s practically no room for that inside the skull. That’s why a severe case of water intoxication can lead to rapid brain swelling which causes seizures, coma, respiratory arrest and ultimately death.
Water intoxication can be worsened when you drink an excessive amount of water and don’t replace the minerals your body has lost. Wikipedia has quite the collection of notable cases of people who suffered and even died from water intoxication. It’s not hard to notice some of the most common causes include: over-hydration during intense and prolonged physical effort (marathons, army march) and water drinking contests.
Places long-term strain on kidneys and circulatory system
Sometimes it’s ok to drink water to prevent dehydration, such as before a strenuous workout. But drinking lots of water throughout the day without actually feeling thirsty as a habit adopted because of one or more of those unfounded water myths can damage your health in subtle ways.
Firstly, your total blood volume increases when you drink more water than you need. As a result you will put an unnecessary strain on your entire circulatory system.
Secondly, all that extra water you drink gets filtered by your kidneys, making them work more, when it really wasn’t necessary. Nephrons are tubular structures in the kidneys that filter blood to form urine. The initial step in filtering blood is done by the glomeruli, networks of capillaries found at the beginning of nephrons. All this extra work can damage the glomeruli, drinking too much water being one of many possible causes (one which can be avoided).
If you’re thinking “I drink lots and lots of water throughout the day and I feel just fine!” be cautious: there are no obvious symptoms. However, it doesn’t mean you’re not damaging your health over time.
Lowers sleep quality
This one is pretty obvious. If you drink lots of water, you’ll need to go to the toilet very often. Most likely, you won’t be able to hold it from bedtime until the next morning. You’ll be interrupting your sleep for a reason which could have been easily avoided. Getting quality sleep is so important for your overall health and far more beneficial than an extra glass of water.