How hard is hard enough?

By Erica Moe | Get Fit

You’re sweating, you’re sore, and you’re short of breath. But is it enough? Is the effort you exert enough to condition your heart and lungs? Is it enough to maximize the calorie burn? If intensity is too low, your heart and lungs may not get conditioned, and you may not burn as many calories as you want.

Intensity Levels

Cardiovascular exercise can be categorized as light, moderate or vigorous. The Centers for Disease Control and Prevention recommends that most adults do 150 minutes of moderate exercise or 75 minutes of vigorous exercise per week. Moderate activities would include walking briskly, water aerobics or playing tennis (doubles). Vigorous activities would include running, swimming laps, tennis (singles) or jumping rope.

Heart Rate Range

There are many formulas to calculate heart-rate ranges. The old faithful is 220-age, and then multiply by the percent of effort. Per the CDC, 50 to 70 percent is considered moderate intensity and 70-85 percent is considered vigorous intensity. The only variable in the equation is age, so there’s no accounting for the fact that you may exercise regularly or perhaps just got off the sofa. If you are a 35-year-old Olympian or a 35-year-old coach potato, your recommended heart-rate rang will be the same. What’s more, it can be difficult to measure your own heart rate during exercise. There may be sensors on cardio equipment at the gym, or you may need to use a heart rate monitor, which can be expensive.

Rating of Perceived Exertion (RPE)

Your rating of perceived exertion is a subjective measure based on how hard you feel that you are working. The scale ranges from six, which is zero effort, to 20, which is maximal effort.  A rating of 12-14 is considered moderate intensity and 15-17 is considered vigorous intensity. There is a correlation between multiplying a person’s RPE rating by 10 for their exercise heart rate. For example: A person with an RPE of 13 could correlate that exercise heart rate to 130 beats per minute. RPE can be an inexpensive and easy way to measure intensity. If you run a 9-minute mile with an RPE of 16, after a few months, you can feel a difference in your RE due to your aerobic conditioning. Hopefully, that same 9-minute mile will only feel like a 14.

Talk Test

The talk test measure takes into account the fitness level of the individual. If you are exercising and are able to talk comfortably, your intensity would be considered moderate. When talking becomes uncomfortable or challenging — you can say a few words, but then need a breath — your intensity level would be vigorous and can be sustained for approximately 20-30 minutes. As it becomes impossible to talk, you will only be able to maintain the intensity for a few minutes.

Even though technology is available, it isn’t necessary. Using RPE, or better yet, the talk test, can be a great way to measure your intensity.

—Erica Moe, M.S., is an ACSM-certified exercise physiologist who writes on behalf of the Mission Valley YMCA where she is fitness director.

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