Meds May Cause High Pulse Rate

DEAR DR. ROACH: I have been on blood pressure medicine (nifedipine) and cholesterol medicine for approximately 30 years. I am 72. Over the past two years, an average of my readings (morning and night) is 135/85, and my pulse is 103.

I exercise 20-25 minutes every day, farm, play golf, work in my wood shop and stay active. Why is my pulse so high? — N.R.

ANSWER: A fast heart rate (over 100 is, somewhat arbitrarily, considered abnormally high) can be a sign of serious illness, so you are wise to be concerned. However, in your case, the high pulse rate likely is a side effect of the nifedipine. Nifedipine works by relaxing muscles in blood vessels throughout the body, causing them to open up (we like to use the term “dilate”) and reducing resistance to blood flow. This causes more blood to flow under less pressure, so nifedipine is a very useful drug for people with high blood pressure, but also those with some types of heart disease.

However, the body often acts to maintain equilibrium, so when a medicine is used on one system, another system tries to compensate. In this case, the heart rate increases in response to the decreased pressure. This is termed “reflex tachycardia.”

A heart rate of 103 is not dangerous in most people with healthy hearts, and it may be that nothing needs to be done. If the heart rate goes higher, and if the person could benefit from slightly lower blood pressure, a physician may use a low dose of a beta blocker, which slows down the heart rate and may protect against heart disease, especially in people at higher risk. Some data show that slower heart rates reduce heart disease risk, but I am just not sure how applicable it is in your case, given your exercise regimen and your medication.

DEAR DR. ROACH: I’ve read that brown and white fat cells may help with obesity. What can you tell us about this, and is it a real solution to losing weight? — G.L.

ANSWER: White fat cells are the regular fat cells we all have (they are white because they are full of fatty acids). These serve as a reservoir of energy that can keep us going during times of little energy intake. This is a critical evolutionary advantage, but in a world without energy deficits, it has proven to be a problem: In some people, fat continues to accumulate, leading to increased risk of diabetes, heart disease and other problems once the fat level becomes too high.

Brown fat is metabolically active fat (it is brown because of high numbers of mitochondria, which contain iron and other pigments). These will (almost literally) burn calories under periods of cold or under certain hormonal changes. The excitement in the field of obesity research surrounds being able to make brown fat more active, or to turn some white fat brown, so that people can expend more energy without exercising. Current treatments for obesity are largely aimed at decreasing calorie intake, so having a second mechanism to treat could be very powerful.

There is no approved therapy to create or activate brown fat yet; however, the research in the field is rapidly increasing, and I hope to see potential therapies in the not-too-distant future.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGood Health@med.cornell.edu or request an order form of available health newsletters at 628 Virginia Dr., Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com.

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