[Sportsandrec] Calculating Heart Rates

[Thornbury, Kelly]

Hi Charlie, 

There are a number of factors that can contribute to higher blood pressure, and stress is just one. Getting into an aerobic exercise program and getting back to a healthier diet will help. Be careful at first, because a lower blood pressure is a side effect of acute exercise, meaning if you run on a treadmill for a workout, then step off, for a while after that (up to a couple hours), your blood pressure will be lower than "normal," and if you are also on a blood pressure medication, you may become dizzy. If you work with a trainer or gym staff, be sure they know what medications you are on. 
One of the biggest changes you can make for lowering blood pressure is to cut down on sodium in your diet. Eating out at fast food places inevitably increases salt intake (they put it on everything...at least twice). Exercise will help reduce stress, and the oxidative stressors (body chemicals produced when you are stressed), which will help with blood pressure too. 
Finding your target heart rate (HR) by taking 220 and subtracting your age, and multiplying by 65-75% is a widely used formula, but not the best. It doesn't take into account your current fitness level, or conditions and medications that can affect HR. A better formula is:
220 minus your age, then minus your resting HR. Then multiply by 40-50%. Finally, add back in your resting HR. This formula takes into account your current fitness level, and is used more often by personal trainers when prescribing exercise intensity levels. The other formula works too, and is simpler for the non-professional, but isn't quite as accurate. 
As for calculating your HR while working out, a heart rate monitor is nice, but I haven't seen a talking one that was very accurate. My OR monitor is always at least 10 beats per minute off (reading higher than I'm actually working out at), and often times when I'm on a bike jumps to over 250 beats per minute, before losing the pulse all together. I've found few exercise equipment measurements to be accurate either, often being up to 10 beats off too. The easiest way is to do the above formulas to find your target heart zone, divide those numbers by 6, then take your HR for ten seconds by checking your wrist and using a stopwatch. If you want your beats per minute, then multiply the exercise number by 6 again. 
Before starting a vigorous exercise program, talk to the doctor who prescribed the blood pressure medication. There are several different types of meds, and they all react differently to exercise, so having your doctor's "advice" is a good idea. 
Also, if you lift weights, reduce the intensity (amount of weight lifted) until the blood pressure is under control. Lifting increases blood pressure acutely (while lifting), and "too high plus higher equals too much higher," increasing the risk of vessel complications. Another topic best discussed with your doctor.