How Much H2O Should I Be Drinking?

What does water do?

The body is made up of roughly 70% water. Water helps to control body’s temperature, lubricates and cushions our joints, and protects sensitive tissues.  It also prevents constipation, lessens burden on kidneys, helps dissolve minerals and other nutrients, and carries oxygen to cells.  Water is processed by water through urination, perspiration, and bowel movements.

How much water do I need a day?

Water is loss from the body through breath, perspiration, urine, and bowel movements.  This water needs to be replaced so the body can function properly.  Twenty percent of our fluid intake comes from food.   Women should consume about 2.2 liters of water and men should consume about 3.0 liters of water a day.  Our ability to sense dehydration increases as we age.

You should drink more water when you sweat during physical activity, are in hot and humid environment, if you are pregnant or breastfeeding, and if you are throwing up are having diarrhea.  If not these factors could cause dehydration.

What is dehydration?

It is caused by an excessive loss of water from the body, which causes a rise in blood sodium levels.  Water loss is usually accompanied by a deficiency in electrolytes.  If dehydration goes untreated it can lead to shock.

To prevent dehydration during working out, you should measure body weight before and after exercise.  Drink 1 pint of fluid for each pound lost.  You should drink about 17 ounces of fluid about 2 hours before exercise to promote adequate hydration and allow time for excretion of excess ingested water.

Fluid Replacement, not just water?

Addition of carbohydrates to fluid replacement would be necessary in exercise that lasts longer than an hour.  This helps prevent fatigue.  So when you are on a long run, grab a sports drink.

Can you have too much water?

Excess water can lead to hyponatremia.  Hyponatremia is a deficiency of sodium in the blood which can cause cell malfunction or can be fatal.  Symptoms can include bloating, puffiness in face and fingers, nausea, vomiting, muscle weakness, headache, and disorientation.  Marathon runners can be prone to this.  To prevent hyponatremia calculate your “sweat rate” ahead of a race by weighing before and after exercising for half an hour at the pace and under the conditions anticipated in the race. For every pound lost through sweating, the racer should drink a pint per hour during the race.