DEAR DR. DONOHUE: I hear contradictory advice about what to drink when exercising in the heat. I run long-distance races and do so year-round. I was taught to drink lots of plain water before and during races. Now I hear that can be dangerous. Should I be drinking only sports drinks? Will you clear up this matter for me? – R.T.

ANSWER: Exercising in hot weather presents two challenges: One is dehydration; the other is overhydration, with a drop in the body’s salt level.

You belong to a special group of people, ones performing prolonged exercise. The following applies not just to athletes, but to all who work in the hot sun for many hours. These people should drink lots of fluid. They should have two 8-ounce glasses of fluid two hours before running a race or before working in the sun. During work or exercise, they must continue to drink, and they can let thirst be their guide. Previously, we had been told that thirst lagged behind our need for fluid, so we were supposed to drink even if we weren’t thirsty. Thirst usually strikes about every 20 minutes. This program takes care of the hydration problem.

The salt problem is an added burden to those who are working hard for more than an hour. Drinking only plain water can cause the blood sodium level to drop. That’s hyponatremia, and it can be dangerous. Confusion, nausea, vomiting and headache are some of the early signs of sodium deficit. If sodium levels continue to fall, people can suffer from seizures, coma and even death. To prevent this, add a quarter teaspoon of salt to every quart of water. Or if you like, drink sports drinks that have sodium added to them.

Prolonged exercise drains muscles of their glycogen, stored sugar. To replenish glycogen, the fluid drunk should have a carbohydrate content of 6 percent to 8 percent. Most sports drinks also contain carbohydrates. You don’t have to use sports drinks, but you do have to be careful about replacing sodium and carbohydrates (sugar).

DEAR DR. DONOHUE: What’s the best way to take care of sunburn? I want to know if I did it right. – M.M.

ANSWER: Cold compresses make the skin less painful and limit the swelling that comes with sunburn. Aspirin is good for adults, but not for children. A bath in cool water to which Aveeno Oatmeal Bath Treatment or baking soda has been added provides pain relief. Don’t apply petroleum jelly, butter or oils to the skin. They delay healing.

If a sunburned person has fever, chills, great swelling or extensive blistering, that person should see a doctor.

DEAR DR. DONOHUE: My wife is a physical-education teacher who spends a great deal of time in the heat, wind and sun. Please provide options for keeping the skin, especially that of the face, looking youthful and smooth. – M.H.

ANSWER: The sun is the greatest destroyer of youthful skin and one of the greatest contributors to skin cancer. Limiting the exposure of the skin to its ultraviolet rays keeps it wrinkle-free and lessens the chances for cancer.

Sunscreens are most important. Your wife and you should apply a sunscreen with an SPF (sun protection factor) of 15 or more, 15 to 30 minutes before going outside, and you both should reapply it frequently. Most sunscreens protect against ultraviolet B rays, and that is good. However, ultraviolet

A rays are also involved in skin wrinkling. Get a sunscreen that contains protection for both. Zinc oxide and titanium oxide are two ingredients that provide such protection. Formerly, they came in white ointments that made users look like they were circus clowns. Now they come in fine particles that don’t draw any attention.

Limiting sun exposure between the hours of 10 a.m. and 4 p.m., when the sun rays are their strongest, limits the amount of skin damage.

Wearing a wide-brimmed hat affords protection to the face.

DEAR DR. DONOHUE: I am 73, in good health and take no medicines. I see doctors only occasionally. In the past few months, I have had several dizzy spells. My doctor sent me to a neurologist, who found nothing wrong with me. The neurologist sent me to a cardiologist, who says I have sick sinus syndrome. I’d like information on it and its treatment. – P.T.

ANSWER: The sinus here is not a head sinus; it’s the heart’s sinus node, located in the upper-right heart chamber. It’s like a metronome, generating a regular, electric impulse 60 to 100 times a minute. When the impulse reaches the lower heart chambers – the pumping chambers – it causes them to contract and pump blood out of the heart.

In sick sinus syndrome, this tiny, electric generator is malfunctioning. At times, it causes the heartbeat to be so slow that an insufficient amount of blood reaches the brain and the person becomes dizzy, comes close to fainting or actually faints. At other times, the node suddenly speeds up so fast that the heart’s pumping action is impaired, causing a shortchanged blood supply to the brain.

A monitor that records all heartbeats for an entire day or days can usually provide evidence of sick sinus syndrome. If the monitor doesn’t come through with the proof, then a special cardiologist, an electrophysiologist, has techniques that can ferret out the problem.

The treatment for sick sinus syndrome is usually a pacemaker. Don’t view that as terrible news. Implanting a pacemaker is not lengthy surgery, and it does not involve a lengthy recuperation. The artificial pacemaker becomes the heart’s new pacemaker, and it dictates the rate of the heartbeat. You won’t be having any more dizzy spells once the heartbeat problem is corrected.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from

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