Appendix A: target heart rate.

Target Heart Rate

Target heart rate (THR) is a common way of judging how hard you should exercise during endurance activities. It tells you how fast the average person should try to make his or her heart beat during endurance sessions. It's not always the best way for older adults to decide how hard to exercise, though, because many have long-standing medical conditions or take medications that change their heart rate. We recommend using the Borg scale shown in Chapter 4 instead. However, some older exercisers who are in basically good health and who like taking a "scientific" approach to their endurance activities may find the THR method useful. Others should check with their doctors first.

For those of you who can use THR, the chart on the next page shows an estimate of how fast you should try to make your heart beat, once you have gradually worked your way up to it. "Gradually" is an important word here. Going immediately from an inactive lifestyle to exercising at the rate shown in the chart is not advised.

One way to reach your THR gradually is to take your pulse during an endurance-type activity that is already a part of your life (walking, for example). Do it at the pace you normally do it, and record your heart rate. From session to session (or over several sessions), increase how hard you work, so that your pulse rate gradually gets faster, over time.

Eventually, you can try to get your heart rate up to 70 to 85 percent of its maximum ability (the rate shown in the chart). Making it beat faster than this is not advised.

Note: The goal is not for your heart rate to be faster all the time--just when you do your endurance activities. In fact, you should find that, as your heart becomes more efficient from endurance exercise, your resting pulse rate is slower than it was before you took up this healthy habit.

DO NOT Use the THR Method If ...

* You take medications that change your heart rate

* You have a pacemaker for your heart

* You have an irregular heart rhythm called "atrial fibrillation"

* You have any other condition that affects your pulse rate. All of these situations can give you inaccurate readings.

Many older adults take medications in a class called "beta blockers" for high blood pressure or some heart conditions. Your doctor can tell you if your heart or blood-pressure medicine is a beta blocker, or if you have other conditions or medications that will affect your pulse rate during exercise. Some eyedrops used to treat glaucoma also contain beta blockers.

Your heart rate is a reflection of how hard your body is working. Beta blockers tend to keep your heart rate slower, so no matter how hard you push yourself, you might never reach the heart rate you are trying for. You might end up exerting yourself too much, as you try in vain to reach a heart rate that your beta blockers won't allow. Being on beta blockers doesn't mean you can't exercise vigorously; it just means you can't rely on your heart rate or on your pulse rate to judge how hard you are working.

How to Take Your Pulse

To take your pulse, press the tips of your index and middle fingers against the inside of the opposite wrist, just below the mound at the base of your thumb, and count how many pulsations you feel in a 10-second period. Multiplying this number by 6 will give you your heart rate. Don't count your pulse for an entire minute. During the minute that you have stopped exercising to take your pulse, your heart will have slowed down, and you won't get an accurate reading.

Age   Desired Range for Heart
      Rate During Endurance
      Exercise (beats per minute)

 40             126-153
 50             119-145
 60             112-136
 70             105-128
 80              98-119
 91              91-111
100              84-102