Whether you’re training for a 10K or just walking around the block, you’ll need to exercise with the proper intensity to lose weight and help your heart. Generally, moderate-intensity exercise is best: Exercise that’s too easy won’t burn enough calories or get you the heart and lung benefits you’re looking for; exercise that’s too hard will lead to injuries, cause burnout and, ultimately, hinder your weight-loss goals.
To gauge your intensity level, follow your heart or, more accurately, your heart rate. By monitoring your heart rate, you can keep it within a target range by adjusting your physical effort.
How fast should your heart beat during exercise? First, you need to determine your maximum heart rate, which is how fast your heart should beat when you exercise as hard as you can. Researchers have been able to simplify this process by calculating a universal maximum heart rate of 220. Subtract your age from 220, and you’ll get your maximum heart rate. If you’re 50, for example, your maximum heart rate is 170 beats per minute (bpm). (See “Medication Alert.”)
Your target heart rate is a percentage range of your maximum rate. Moderate-intensity exercise should raise your heart rate to between 50 percent and 70 percent of your maximum. For example, if you’re 50 years old:
- 50 percent of 170=85 bpm
- 70 percent of 170=119 bpm
Thus, to exercise at moderate intensity, your heart rate should stay in the target range of 85 to 119 bpm. Working out in this range for about 30 minutes gives you an effective workout.
As you become more fit, your target heart rate percentage needs to increase so you can continue to gain cardiovascular benefits and lose weight. Aim for 70 percent to 85 percent of your maximum heart rate.
So, how can you determine whether you’re in the “zone”? To check your heart rate, feel for your pulse with the tips of your index and middle fingers over the radial artery at the outside of your wrist when your palm is facing up. Begin counting on a beat, starting with zero. Take a full 60-second count of the beats or count the beats for 30 seconds and multiply by 2. (You can also count for 10 seconds and multiply by 6.) Using a watch or clock with a second hand will ensure more accurate results.
You can also use a heart-rate monitor as you exercise. A monitor eliminates the need to stop, count and calculate. It typically consists of two components: a transmitter on a strap worn around your chest, which detects your heartbeats, and a wristwatch-like receiver that displays your heart rate.
The American Heart Association suggests you aim for the lower part of your moderate-intensity target zone (50 percent) when starting an exercise program. Gradually build up to the higher end of your target zone (70 percent). After several months, you may be able to hit the vigorous 85 percent mark. If you can’t, don’t sweat it. Regular, moderate exercise is all you need to keep your heart and lungs healthy.