CAUTIONS AND CAVEATS

❚ If you don’t have a heartrate monitor, it’s possible, albeit cumbersome, to train by heart rate without one. Find a place where your pulse can be strongly felt, such as on your neck. Count your pulse for 10 seconds, then multiply that number by six to get your current heart rate. On-the-go measurements are possible in some activities, such as stationary cycling, but if you’re running, you might need to briefly interrupt your workout. Most modern gym equipment includes a grip or other way to get a snapshot of your heart rate.

❚ Allow for heart-rate drift. Except during low-intensity and easy workouts, your heart rate will gradually increase over the course of a workout. That phenomenon, known as heartrate drift or cardiac drift, occurs sooner and to a greater degree in hot, humid weather. (When it’s hot, your heart pumps more blood to your skin in an effort to keep you cool, resulting in a higher heart rate at the same pace.)

To account for heart-rate drift, start exercising at the lower end of the range for a given workout. On hot days, keep your heart rate in the right range and adjust your pace, incline or resistance as needed, conditioning coach Debra Atkinson advises.

❚ For water workouts, if you’re tracking your heart rate while swimming or doing water aerobics, adjust your intensity ranges down by 10 to 12 beats. For example, if your target heart rate for a moderate-intensity workout is usually 140 to 150 beats per minute, aim for 130 to 140 in the water. That adjustment is necessary because water pressure on the body increases how much blood returns to and is pumped from the heart.