Find your target zone: what's the best way to determine my ideal heart rate, or target zone, for exercise? … and more of your questions answered here

Shape, Nov, 2004 by Suzanne Schlosberg

Q What's the best way to find my maximum heart rate? I've heard the "220 minus your age" formula is inaccurate.

A Yes, the formula that involves subtracting your age from 220 is "very old school and has no scientific background," says ultra-endurance athlete Sally Edwards, author of several books about heart-rate training, including The Heart Rate Guide Book to Heart Zone Training (Heart Zone Publishing, 1999). This formula has remained popular over the years because it's simple, but it assumes that your maximum heart rate will decrease by about one beat per year, which isn't true for everyone. "Everyone's max heart rate is hugely different, regardless of age or fitness," Edwards says. "The only way to know it is to test it."

The most precise tests are done in a lab. While you're running on a treadmill or pedaling a stationary bike, the tester will gradually crank up the intensity every 15 seconds and within a few minutes you'll reach your maximum heart rate. A more practical, less grueling approach is to test yourself using a "submax" method; you'll increase your intensity to a certain below-maximum level, then use various formulas to extrapolate what your maximum would be. A submax test isn't as precise as a max test, Edwards says, "but you can get a pretty accurate idea, within five beats." She recommends taking two or three different submax tests and averaging the results.

One example of a submax test is the step test. Step up and down on an 8-to 10-inch step for three minutes without pausing between steps, then take your average heart rate (HR) for one minute (see last question on next page for information on heart-rate monitors that can determine this) and add the appropriate estimate factor for your fitness level using the formula that follows. To ensure consistency, keep both the step height and the cadence the same each time you test yourself.

_________   ________ = ________
Avg. HR     Estimate   Estimate
last min.   factor     max HR

ESTIMATE FACTOR:
Poor shape = 55; Average shape = 65;
Excellent shape = 75; Competitor = 80

You'll find several other submax tests at heartzones.com. Once you've estimated your maximum heart rate, you can base your exercise program on different percentages of this maximum. The American College of Sports Medicine recommends working out in your "target zone"--from 55 percent to 90 percent of your maximum heart rate--to burn the most calories and gain aerobic fitness without risking overexertion or injury. Exercising near the 90 percent range will result in higher calorie burn, but it's tough to maintain this level for long periods. Interval training, or alternating between the top, middle and lower ends of your target zone, is one way to gradually train your body to tolerate the higher intensity of the 90 percent range.

Q Each month I find terrific fitness plans in Shape, but then the next month I see different plans. Is it better to follow one plan to completion for six to eight weeks, then switch to a new program? Or should I try a new plan each month?

A "Whether you should switch plans depends on how fit you are, where you are in your current plan and whether you're seeing results," says Linda Shelton, Shape's fitness director. If you're a beginner, Shelton suggests sticking with a six- to eight-week plan to completion so that you build a strong base and get into an exercise groove, focusing on your form and increasing your intensity gradually. But if you're already fit, Shelton says, trying a new program each month can be a great motivator as well as a boon to your fitness level: "Changing your plan helps keep your body from getting too comfortable and staying stuck on a plateau." You also can mix and match, incorporating elements of a new plan into the program you're already following.

Also consider whether you are pleased with the results of a particular plan--are you enjoying the workouts, feeling more fit and gaining energy? "Not every program is for every person," says Shelton. "Even though we feel all of our programs are fantastic, individuals do respond differently."

However, don't dump a program simply because you haven't lost weight as quickly as you'd like. "If you have a lot of weight to lose, it won't happen in a month, regardless of the plan," Shelton notes. Weight loss requires both exercising more and eating less, as well as a healthy dose of patience. Don't aim to lose more than 1 pound per week.

Q I've been swimming competitively since I was 7 years old. I am now 24, and my shoulders are very broad. I lift weights every other day. Should I stop working out my shoulders? I don't want them to get any bigger.

A "By all means you should still work out your shoulders," says Monica Bocks, a certified fitness trainer at Sierra Nevada Dance and Fitness in Truckee, Calif. "I understand your concerns about being broad through the shoulders, but remember that strong shoulders will allow you to continue to swim at a competitive level." What's more, if you neglect any muscle group in the gym, you increase your risk for injury. "A good weight routine should be balanced, working all major muscle groups," Bocks says.