Traditional Guidelines for Physical Activity (Cont'd)

Intensity

Intensity is how hard a physical activity session is. Intensity is often categorized into low, moderate, and high levels. There are many misconceptions about intensity. The standard of high-intensity physical activity was common when today's elders were young adults, and persisted until the 1990s. Moderate-intensity physical activity provides many health benefits and appeals to most older adults. High-intensity physical activity also promotes fitness, but it is not necessary for older adults to do high-intensity physical activity in to order get health benefits.

There is also some confusion between high-impact and high-intensity physical activity. Impact refers to the likelihood of injury and is not related to intensity. A low-impact activity can have moderate or high intensity, which is why it is beneficial to cardiovascular health.

How to Know What High- and Low-Intensity Feels Like

The aerobic exercise boom of the 1970s popularized the concept of being physically active in your target heart-rate zone. Heart rate, or how hard the heart is beating while you are being physically active, is a measure of your physical activity intensity. Individuals can determine whether they are being active at the desired intensity by taking their pulse while being physically active. If the pulse rate is less than their target heart-rate zone, they can do the activity harder; if it's higher, they can reduce intensity.

Older adults who have difficulty accurately taking their pulse or who take beta-blocker medication for heart conditions (which artificially maintains a low heart rate) should choose an alternative approach to measuring intensity from the two other methods listed below.

Calculating Your Target Heart Rate Zone
How To Take Your Pulse

Alternative Methods to Evaluate Physical Activity Intensity

There are two good, easy alternatives to using the target heart-rate zone method to determine physical activity intensity that are well suited to older adults: the Borg Rating of Perceived Exertion Scale, and the Talk Test.

Rating of Perceived Exertion

Gunnar Borg developed the Rating of Perceived Exertion, or RPE scale, as a self-assessment of physical activity intensity.³⁴ The scale goes from level 6 (least effort) to level 20 (maximum effort). The individual uses the scale to assign a number to how hard she feels she is being active, based on her own assessment of her total amount of exertion and fatigue.³⁵

Although it is a subjective measure of an individual's intensity, studies have found that the Borg scale correlates well to heart-rate levels (the number on the scale x 10 = approximate heart rate). The "somewhat hard" rating of 13 corresponds to approximately 70 percent of maximum heart rate (mid-range of the target heart-rate zone), and the "hard" rating of 16 corresponds to approximately 85 percent of maximum heart rate (high end of the target heart-rate zone).³⁶

The Borg Rating of Perceived Exertion (RPE) Scale

Least effort
6
7	Very, very light
8
9	Very light
10
11	Light
12
13	Somewhat hard
14
15	Hard
16
17	Very hard
18
19	Very, very hard
20
Maximum effort

A simplified version of the Borg scale ranges from 1 to 10, which most individuals find easier to relate to than the original scale.³⁷ The "somewhat hard" rating of 5 corresponds to approximately 70 percent of maximum heart rate, and the "hard" rating of 7 corresponds to approximately 85 percent of maximum heart rate.³⁸

1	Very, very light
2	Very light
3	Fairly light
4	Light
5	Somewhat hard
6	Moderately hard
7	Hard
8	Very hard
9	Very, very hard
10	Extremely hard

The Talk Test

The Talk Test is another self-assessment of physical activity intensity that correlates well to heart-rate levels. During aerobic (endurance) physical activity, individuals can self-administer the Talk Test by saying a few sentences out loud. If the person can easily talk (or sing!) and is not the least bit out of breath, he is being active at an extremely low intensity. On the other hand, if an individual is so out of breath that she cannot say a few sentences, she is being active at an extremely high intensity (probably too high). As with the other methods, the individual can compare the assessed intensity with the target intensity, and adjust the effort if desired.

³⁴ Cotton, p. 137. cf. Borg, G. (1998) Borg's Perceived Exertion and Pain Scales. Champaign, IL: Human Kinetics.

³⁵ American College of Sports Medicine. (2000) ACSM's Guidelines for Exercise Testing and Prescription, (6th ed.). Baltimore, MD: Lippincott Williams & Wilkins.

³⁶ NIA Guide, p. 28; Cotton, pp. 116, 135-36.

³⁷ To order laminated aerobic intensity wall charts in color contact Young Enterprises in Kansas: telephone (800) 765-3975, website: www.youngposters.com

³⁸ NIA Guide, p. 28; Cotton, pp. 115, 134-37.