DEAR DR. DONOHUE: Every year for the past five years, I go to Colorado with a group of friends to ski. This year, my skiing lasted only three days. I developed pain on the thumb side of my right wrist. It was so bad I couldn’t hold on to a ski pole.

I found a doctor who was staying at the same place I was. He said I had skier’s thumb and told me I should stop skiing. I did. Now, 10 days later, my wrist still hurts. What should I be doing for it?

No one in my skiing group nor I had ever heard of this. — T.C.

ANSWER: Skier’s thumb has many other names. One is de Quervain’s disease, and another is Washerwoman’s disease (the name picked by Dr. de Quervain). Strangely, it happens to pregnant women, too. I don’t know why.

It’s an inflammation of the tendons that move the thumb. They’re the same tendons used for a firm grasp on ski poles.

Tendons are bundles of collagen fibers. Collagen is a body protein used for support and as the substance in many tissues that require constant motion. It’s the stuff of scars. Collagen has lots of water in it. Inflamed tendons lose water, and they can’t tolerate the constant stress that they usually put up with. They have to regain their water, something that happens only with rest. A wrist splint will help you rest those tendons during the day.

Ice the painful area for 15 minutes every four hours. If icing doesn’t bring relief, switch to heat. Tylenol or a nonsteroidal anti-inflammatory medicine (Aleve, Advil, Motrin) eases the pain.

You should be free of pain in three weeks or so. If things haven’t resolved by then, you must see a doctor. Other conditions have similar symptoms.

DEAR DR. DONOHUE: I vaguely recall you writing about this before, but I wonder if you would repeat it. It’s the idea that a person can get rid of more fat by doing light exercises. The idea interests me if it’s true. I remember you were not too in favor of this, but I can’t remember why. Why not? — H.L.

ANSWER: It is an appealing idea, but doesn’t make sense to me.

It is true that low-intensity exercise burns more fat than does high-intensity exercise. Close to 50 percent of energy burned in light exercise comes from fat stores.

With high-intensity exercise, the kind that leaves you panting, more energy comes from glycogen, stored body sugar.

But the arithmetic tells the story. Say you burn 200 calories in light exercise. Fifty percent of those calories come from fat, so you have burned 100 calories of fat.

With intense exercise, around 40 percent of energy is furnished by fat-burning. If you burn 500 calories doing intense exercise, 40 percent of those calories come from fat — 200 calories. The high-intensity exercise is the clear winner when it comes to fat-burning.

DEAR DR. DONOHUE: My son played in two basketball competitions, one right after the other. When they were over, I took him for pizza. He ate an entire large pizza. He also got sick after doing so. He threw up. He thinks he had food poisoning. I think he ate too much too fast. What do you think? — M.G.

ANSWER: I don’t think it was food poisoning. Food poisoning seldom happens so quickly after eating.

Overeating immediately after exhausting exercise makes some people sick. The explanation is that the buildup of lactic acid that comes during hard exercise hasn’t completely dissipated. It makes some people sick to their stomachs.

Dehydration is another explanation. Stuffing lots of food into a body that’s short on fluids can also cause nausea and vomiting.

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 www.rbmamall.com.