Heat and Hydration

Much of the United States is experiencing a heat wave this week, so it’s a good time to revisit the issue of hydration.

With temps in the high 90’s and humidity making it feel even hotter, it is best to limit time outdoors if possible. But when you must be exposed to the heat, it is imperative that you drink much more that you would normally. If you are working or exercising outdoors, you may need a sports drink as well. Don’t reach for the sports drinks routinely however. While they have their place, they add sugar and calories you may not need. Athletes engaging in continuous, strenuous exercise need the sugar to fuel their muscles. If you are not exercising, the sugar will just be stored as fat. Electrolytes in these drinks are needed if you are sweating profusely, as that is when you lose them. For the average person, water alone would be best.

How much? On a normal day, a good rule of thumb is 8 (women) to 12 (men) glasses. That is what we lose through perspiration, normal metabolism and elimination. On a hot day, you need more, depending on how much you sweat.

Thirst not a reliable indicator of need for water. By the time we feel thirst, we are already dehydrating. Also, the thirst mechanism fails with aging.

Be safe. Drink water throughout the day. Eat fruits and yogurt, which have high concentration of water. And only consider sports drinks when you are exercising your muscles and sweating a great deal.

Water, Water Everywhere . . . . .

It is HOT today. How hot? How about in the 90’s, but it feels over 100 degrees due to high humidity. An air quality alert is in effect as is a heat alert. “Cooling centers” are open in public spaces like libraries and senior centers, some schools, etc. Take your time shopping at the Stop and Shop, where it is always cold. We’re in for several more days of this, so listen up!

When we were little, we learned that our bodies were comprised of about 90% water. I thought, “How could that be? Wouldn’t we just fall like a shapeless heap? Bones can’t be made of water; they hold us upright.”

Well, I learned since then, the number is more like 60% (still quite a lot). Water is one of the essential nutrients, as is protein, carbohydrates, fat, vitamins and minerals. Water is essential as it carries nutrients and wastes through the body, is needed for metabolic functions, is a solvent for water soluble vitamins and minerals, and supports the molecular structure of body cells. It lubricates and cushions the joints, regulates body temperature and maintains blood volume. Because it carries the electrolytes sodium and potassium, it is important to proper heart function. Are you listening now?

Most people are in a constant state of dehydration. We, as a nation, don’t drink enough. By the time we are thirsty, assuming the thirst mechanism is working properly, we have lost 2% of our body fluid volume. Add to that that many of our thirst mechanisms don’t function well, particularly as we age, and it can spell trouble.

Dehydration can be serious. If you lose 1-2% of body fluid, you experience thirst, fatigue, weakness, loss of appetite and discomfort. At 3-4%, your physical performance is impaired, your mouth is dry, urine output is reduced (leaving more toxins in your body), your skin flushes and you experience apathy and/or agitation. At 5-6%, you can’t concentrate, may get a headache, will be irritable, and sleepy. Your respiratory rate will rise, putting strain on your cardiovascular system and your body will be unable to regulate temperature. At 7-10%, dizziness, muscle spasms, loss of balance, delirium and collapse are likely. When thirst is not motivating you to take in fluids, you can pass through these stages quickly.

Water needs vary by person, but a good rule of thumb for an average person is to take in 8-12 cups of water form all sources. Juicy fruits like watermelon provide a lot of water, vegetables have some, all drinks count, but don’t use sports drinks as they contain high doses of sugars and sodium They are best only when exercising vigorously, for an hour or more. Be sure to increase your intake when exercising, especially if it is in hot weather. Do your outdoor exercise early in the day or late in the evening to lessen the risk of dehydration.

Water is essential. As essential as air. We can’t live without it. Be aware of how much you are taking in. Don’t wait until you are thirsty as it is an unreliable indicator of need. By the time a normal person is thirsty, s/he has already lost 1-2% of body fluid. In the elderly, it is especially critical to drink on schedule, as thirst is a function that declines with age.

Respect your body’s need for water. It is the MOST essential nutrient!