To improve overall cardiovascular health, the American Heart Association recommends at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise per week – or a combination of the two for adults.
But what exactly do moderate and vigorous exercise mean and how do you know if you’re working out at the right intensity?
There are a couple different ways to measure the level of intensity at which you are exercising and that level is based on your individual fitness level and overall health.
The Borg Rating of Perceived Exertion (RPE)
As defined by the Center for Disease Control and Prevention, this is a way of measuring physical activity intensity level. Perceived exertion is how hard you feel like your body is working. The RPE is based on the physical sensations you experience during physical activity, including:
- increased heart rate,
- increased respiration or breathing rate,
- increased sweating, and
- muscle fatigue.
A high correlation exists between a person's perceived exertion rating times 10 and the actual heart rate during physical activity; so a person's exertion rating may provide a fairly good estimate of the actual heart rate during activity (Borg, 1998). For example, if a person's rating of perceived exertion (RPE) is 12, then 12 x 10 = 120; so the heart rate should be approximately 120 beats per minute.
Note that this calculation is only an approximation of heart rate, and the actual heart rate can vary quite a bit depending on age and physical condition. The Borg Rating of Perceived Exertion is also the preferred method to assess intensity among those individuals who take medications that affect heart rate or pulse.
During your workout, use the RPE Scale to assign numbers to how you feel. Self-monitoring how hard your body is working can help you adjust the intensity of the activity by speeding up or slowing down your movements.
Through experience of monitoring how your body feels, it will become easier to know when to adjust your intensity.
- Moderate-intensity physical activity is defined as - physical activity done on a scale relative to an individual's personal capacity, moderate-intensity physical activity is usually 11-14 on a scale of 1 to 20.
- Vigorous-intensity physical activity is defined as - physical activity done on a scale relative to an individual's personal capacity, vigorous-intensity physical activity is usually 17-19 on a scale of 1 to 20.
Examples of Moderate Intensity:
- Walking briskly (3 miles per hour or faster, but not race-walking)
- Water aerobics
- Bicycling slower than 10 miles per hour
- Tennis (doubles)
- Ballroom dancing
- General gardening
Examples of Vigorous Intensity:
- Race walking, jogging, or running
- Swimming laps
- Tennis (singles)
- Aerobic dancing
- Bicycling 10 miles per hour or faster
- Jumping rope
- Heavy gardening (continuous digging or hoeing)
- Hiking uphill or with a heavy backpack
For example, if you are a walker and you want to get moderate-intensity activity, you would aim for a RPE level of 12-13 to get the recommended level of activity by the AHA. If your muscle fatigue and breathing seems about an 8, then you would want to increase your intensity. On the other hand, if your exertion was about a 15, you would need to slow down to achieve the moderate-to-vigorous intensity range.
Ratings are on a scale from 0 to 20. Zero (“0”) expresses how hard you’d be working if you were lying in bed and “20” relates to sprinting as fast as you possibly can. You can also use the “talk test” to estimate your relative intensity. In general, most people are able to talk or hold a conversation during moderately intense activities. By comparison, holding a conversation or saying more than a few words before stopping to take a breath is more difficult during vigorous activities.
Ratings of Perceived Exertion:6 No exertion at all
7 Extremely light (7.5)
9 Very light
13 Somewhat hard
15 Hard (heavy)
17 Very hard
- Target Heart Rates
- AHA Physical Activity Recommendations in Adults Infographic
- AHA Physical Activity Recommendations in Kids Infographic
Last Reviewed 3/2014