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Fitness Focus: Copy-and-Share: Improving JOURNAL/acsms/04.02/00135124-200509000-00004/ENTITY_OV0312/v/2017-07-29T053957Z/r/image-pngO2max

Thompson, Dixie L. Ph.D., FACSM

ACSM's Health & Fitness Journal: September-October 2005 - Volume 9 - Issue 5 - p 4

The third and final part of this copy-and-share series on maximal oxygen consumption provides guidelines on how to achieve a safe and beneficial cardiorespiratory overload.

Dixie L. Thompson, Ph.D., FACSM, is the director of the Center for Physical Activity and Health and an associate professor in the Department of Exercise, Sport, and Leisure Studies at the University of Tennessee, Knoxville.

This is the third of a three-part series on maximal oxygen consumption, abbreviated O2max. In previous columns, O2max was defined and the relationship between it and health and performance was discussed.

Improving O2max can lead to health and performance benefits. To improve O2max, a cardiorespiratory overload is needed. This can be done in a variety of ways depending upon goals and personal preferences. The amount of improvement in O2max depends upon genetic potential, initial level of fitness, and the type of training program.

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Symbol ACSM Recommendations

ACSM has established the following recommendations for the improvement of cardiorespiratory fitness:

  • Frequency: 3 to 5 days per week
  • Intensity: 50% to 85% of heart rate reserve (40% to 50% may be a good starting place for those with very low fitness)
  • Duration: 20 to 60 minutes
  • Type of activity: continuous aerobic exercise using large muscle groups such as jogging or swimming


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Symbol Calculating Target Heart Rate

To determine the appropriate exercise intensity, 50% to 85% of heart rate reserve (HRR) is the recommended target heart rate range. First, estimate maximum heart rate (HRmax) by subtracting your age from 220. For example, a 40-year-old individual would have an estimated HRmax of 180 beats per minute (bpm). Then, to calculate HRR, use your resting heart rate (RHR). To calculate 50% of your HRR use the following formula:



For example, if a 40-year-old man has a RHR of 70 bpm, then 50% of his HRR would be 125 bpm and would represent the lower end of the target heart rate range.



To calculate the upper end of the HRR range, use the same formula but substitute 0.85 for 0.5. Attempt to keep your heart rate between those two extremes during aerobic workouts.

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Symbol Avoiding Injury

Injuries are linked with doing too much exercise before the body adapts. When beginning to exercise regularly, start by exercising at the lower end of your HRR range and duration range. As endurance builds, increase exercise intensity and duration. Cross training incorporates different types of activities into your exercise routine and can lower the chance of overuse injuries. For example, you might cycle 3 days per week and play tennis on 2 other days.

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Symbol Training for Competition

Athletes must exercise at higher intensities, more frequently, and for a longer duration than is required for general health/fitness improvement. Endurance athletes typically combine long bouts of moderately high intensity exercise with days of high intensity training. A personal trainer or coach who specializes in developing training programs for athletes can design individualized programs for O2max improvement.

© 2005 American College of Sports Medicine