DEAR DR. DONOHUE: I’ve talked with other runners, so I know I’m not the only one with this question. What gives a person a “second wind”? I can feel totally wiped out about three-quarters into a run, but if I keep running, I get a burst of energy and am able to finish. Is there any way to capitalize on this? – B.R.

ANSWER: The totally wiped-out feeling is a sign that your body has run out of glycogen. Glycogen is carbohydrate stored in muscles, in the liver and in other places. It is the major source of fuel for muscles, and it is high-octane fuel. When glycogen stores are depleted, the body turns to fat as its fuel source. That’s when you feel a surge of new energy – the second wind. It’s not something you can control. It happens automatically. I’m not sure what you mean by capitalizing on it. You can load up on carbohydrates before a long run and delay the switch to fat-burning. By doing so, you provide the body with its preferred fuel source. Carbohydrate loading used to be a much-discussed method for marathon runners to fill their glycogen stores over their normal capacity. Runners deliberately deplete their glycogen about four or five days before a big race. Then they go on a high-carbohydrate diet. Their glycogen-starved muscles are so avid for carbohydrate that they take in much more than they usually can. That prolongs runners’ stamina and delays the necessity to switch to fat for fuel.

DEAR DR. DONOHUE: I am a 59-year-old male in good health. I work out regularly on a treadmill for 30 to 40 minutes three times a week. I cannot diminish the size of my male breasts. What exercise or diet will help ? – R.S.

ANSWER: If you’re overweight and if your breasts are large because of stored fat, then a weight-reduction diet will rid you of it. Fat will be lost from all fat depots, not just the breasts.

There is no exercise that selectively removes fat from one area. If the breasts are enlarged due to true breast tissue, the condition is gynecomastia. It happens to just about every boy going through puberty, when there is a relative imbalance between male and female hormones. When the hormone balance is restored, the breasts almost always return to the normal male size.

Gynecomastia happens to older men when, once again, there is a relative imbalance between male and female hormones. Your doctor can distinguish breast tissue from fat and run a few screening tests to make sure nothing bad is happening. The only way to get rid of true breast tissue is surgical removal.

DEAR DR. DONOHUE: I read the letter of the mother who was worried about her son playing football because she, as a high-school student, had seen a football player die. You told her to forget that past incident. I can’t forget my 24-year-old son, the picture of health, dying suddenly in a triathlon due to an undiagnosed congenital heart condition called left main artery atresia. His only symptom might have been a fainting incident in high school while jogging. Many tests were done then, but the doctor gave him a clean bill of health. If an automatic external defibrillator had been present at the triathlon, he might be alive today. I advise parents who have had a child die of a sudden cardiac death to go to www.parentheartwatch.org and find out what is being done to educate the community about this. – R.N.

ANSWER: No one can appreciate the sorrow of parents losing a child except a parent who has experienced such a tragedy. Your son’s condition is a rare condition of a heart artery. Anomalies of heart arteries account for about 20 percent of sudden heart deaths in young athletes. Those changes are difficult to detect. Signs that should make everyone sit up and take notice are chest pain, fainting or irregular heartbeats occurring during exercise. Even then, detection is still difficult. I, like you, would love to see more defibrillators available at all athletic events.

DEAR DR. DONOHUE: Would you please discuss the problem of arteriosclerosis and how it affects the body? Is it connected to cholesterol? Is there any connection with hardening of the arteries? What are its causes and treatment? I am sure there are a great many people affected by this disease. – A.S.

ANSWER: “A great many people” is an understatement. It’s the No. 1 cause of death in Canada and the United States. Arteriosclerosis (are-TEAR-ree-oh-skluh-ROW-suss) is artery hardening – “sclerosis” means “hardening.” Atherosclerosis (ATH-ur-oh-skluh-ROW-suss) – a buildup of cholesterol and fat in arteries – is the most common kind of arteriosclerosis. Cholesterol has everything to do with it. The causes are familiar to you, but they might not have been spelled out as the causes of artery hardening. High blood cholesterol and high LDL cholesterol (the bad cholesterol) deposit within artery walls.

The deposit grows and eventually obstructs blood flow through the artery. If a heart artery is affected, the result is a heart attack. If a brain artery is affected, the result is a stroke. Any organ whose feeding artery is blocked suffers a similar fate. Aging, obesity, inactivity, high blood pressure, smoking, family genes and diabetes contribute to artery hardening. You probably heard all this in relation to heart attacks, but the basic problem is plugged arteries.

Treatments are familiar to you too. If a person suffers from diabetes or high blood pressure, treatment consists of keeping both under control. Smokers have to stop smoking; smoking fosters artery hardening. Being a couch potato leads to artery obstruction, so exercise is a must. Walking is something that just about everyone can manage.

Obese people have to lose weight. Cholesterol must be lowered to acceptable levels. If diet doesn’t bring it down, then people should be on cholesterol-lowering medicines.

Genes and aging can’t be changed. The other risks can.

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.