In the last two weeks, we learned about the importance of both identifying and treating heat stroke and heat exhaustion, as well as how to be safe in and around water.
This week I’d like to address another situation that is often brought about by a rise in temperatures … dehydration.
Dehydration simply means your body doesn’t have as much water as it needs. Technically speaking, dehydration comes about when one loses 2 percent of one’s body weight in fluid. Also, when it comes to sweating, remember if your skin is damp, you’ve lost pints. If it’s wet you’ve lost quarts.
Obviously, dehydration is facilitated when temperatures are higher, but there are several other causes that may have nothing to do with heat.
In addition to sweating, the body can lose excessive amounts of water from vomiting, urination, diarrhea and even breathing.
If intravascular (within blood vessels) fluid volume is low, the body merely compensates by shifting water from within cells into the blood vessels.
Here’s the problem. If cells don’t have enough water inside, the cell’s organelles (little organs within the cells) can’t do their jobs, therefore the body’s cells don’t work properly. In mild cases (1 – 2 percent water loss) of dehydration, symptoms may include unexplained tiredness, thirst, decreased urine volume, abnormally dark urine, headache, lack of tears when crying, dry mouth and irritability.
Symptoms of moderate dehydration (5 – 6 percent water loss) may include no urine output, extreme sleepiness, lethargy, sunken fontanel (soft spot) in infants, sunken eyes and fainting. In cases of severe dehydration (10-15 percent water loss), symptoms include tingling in one’s limbs (paresthesia), spastic muscles, dim vision and possibly shriveled skin. Losses greater than 15 percent are usually fatal.
Mild to moderate dehydration can usually be reversed by drinking more fluids, but severe dehydration requires immediate medical treatment.
By far the safest approach is to prevent dehydration.
One thing I recommend you not do is rely on your sense of thirst when trying to hydrate yourself. One reason is that in people over age 50, the body’s thirst sensation diminishes, and continues to diminish with age.
When I do consultations, I ask if the client drinks much water. If they say yes, I ask if they are thirsty often, and invariably they say, “ yes.” I then ask if they know someone who doesn’t drink much water, and they usually say they do. I then ask if that person is often thirsty. They almost always say “no.” I then ask them “Doesn’t that seem backward?”
You’d think if someone drank lots of water he wouldn’t be thirsty, and you’d think if someone didn’t drink much water, they would be thirsty, but it doesn’t work that way. Why? Here’s why.
Always remember your body can’t tell the difference between what you choose to do and what you have to do. Let me give you an example.
Say you were stuck in the desert, and couldn’t get water. You’d begin to thirst to death, so your brain would then shut your thirst mechanism down so you wouldn’t suffer so much.
Well, when you choose not to drink water, your brain doesn’t know you’re choosing not to drink, it just knows water isn’t coming through there.
Conversely, when you drink lots of water, your brain says “I can afford to be thirsty, because there’s plenty of water available. ”
When it comes to the question of how much water one should drink a day, there are no easy answers, because of varying factors like age, health, activity level, and geographic location.
One good approach is the 8×8 rule.
Drink eight 8-ounce glasses a day. I recommend athletes drink two 8-ounce glasses before participating in any sport.
Also, remember muscle is 70-75 percent water, so if you’re dehydrated, it’s like running on flat tires. In addition to water, you need to replace electrolytes like sodium, potassium, chloride, calcium and magnesium. Electrolytes, carry electrical charges through muscles, and without them you could cramp.
Remember too, that drinking alcoholic beverages dehydrates you, so choose water or sports beverages instead.
Diet or exercise question?
Email me at dwcrocker77@gmail.com or visit fitness4yourlife.org.
David Crocker of Landrum has been a nutritionist for 24 years. He served as strength director of the Spartanburg Y.M.C.A., head strength coach S.C. state champion girls gymnastic team, USC-Spartanburg baseball team, Converse college equestrian team, lead trainer to L.H.Fields modeling agency, taught four semesters at USC-Union. Crocker was also a regular guest of the Pam Stone radio show.