Dear Dr. Roach: I鈥檓 54 years old, 5 feet, 1 inch tall and weigh 110 pounds. I鈥檓 not medicated and I go for yearly physicals with my MD. I exercise regularly and have done so for most of my adult life. When I ride my bike outdoors, I鈥檓 usually out for a good three hours. My heart rate averages 155, at its highest 175. I鈥檓 always still able to breathe and talk, and when I rest it comes down quickly. This is a lot higher than the target heart-rate zone for my age (116-149). What are your thoughts? A.D.C.
Target heart rate is a good example of a characteristic that varies a great deal from one person to another. The ranges that are published are right for many people, but not for everybody. The formula for women is even less accurate than the one for men. It is particularly bad for athletes, who tend to have heart rates similar to those of younger women. The fact that your heart rate comes down quickly is another sign of good fitness.
The best way to find your maximum heart rate is to have a supervised maximal exercise session. However, being able to talk during exercise is a good way to regulate your exercise.
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Dear Dr. Roach: I understand that THC is the active drug in marijuana. Where medical marijuana is legal, why isn鈥檛 THC extracted and prescribed? T.A.
Synthetic THC has been available for years as the prescription medication dronabinol (Marinol). It is Food and Drug Administration-indicated to treat nausea associated with chemotherapy and to help people with advanced HIV gain weight, but is also used for pain, headaches and other symptoms. However, many people feel the synthetic drug does not work as well as actual marijuana, which has several types of THC, not just the delta 9听that is in Marinol.
Medical opinion is divided about whether natural marijuana has any benefit over the pharmaceutical product. In addition to the many other active substances in natural marijuana, oral use is different from smoked, since any drug taken orally must go through the liver, which metabolizes it into yet more听compounds. The American Medical Association has recommended further study before it is recommended for general use.
My limited experience is that synthetic Marinol is very effective for a subset of people.
Dr. Roach regrets he can鈥檛 answer individual letters, but will incorporate them in听the column whenever possible. Email [email protected]
