Training-Sensitive Zone
Training Sensitive Zone
Maximum exercise heart rate is on most occasions determined after 2 to 4 minutes of all-out effort during a given form of exercise. It must be noted that this level of exercise, requires great motivation and is not advisable for adults to attempt who are not medically or at a physical level which the test requires. It is certainly not for individuals with known conorary heart disease. Added to this for safety reasons, persons place themselves in the ‘average’ category and make use of the ‘age-predicted maximum heart rates as in the image link supplied below.
It is acceptable that persons of certain age groups have differing HRmax values, the difference in accuracy (generally, +- 10 beats per minute is the standard deviation for any age-predicted HRmax) is on ‘most occasions’ of little significance in establishing an effective training program for healthy people. Maximum heart rate can be established as 220 subtract the person’s age in years, with values being independent of race or sex in children and adults. (Note: This decrease in maximum heart rate with age is probably the result of reduced sympathetic output from the medulla and possibly changes in the inherent characteristics of the S-A node) Although the formula represents an acceptable ‘rule of thumb’, it is only an estimate. Within normal variation, about 95% (+- 2 standard deviations) of 40-year-old men and women have a maximum heart rate between 160 and 200 beats per minute. The image also depicts the ‘Training-senstive Zone’ in relation to age. Conditioning of the aerobic systems can be achieved by maintaining the exercise heart rate is within this zone.
A 40-year-old woman (or man) wishing to train at moderate intensity but still achieve the threshold level would select a training heart rate equal to 70% of age-predicted HR max, that is, a target exercise heart rate of 126 beats per minute (0.70 x 180). Then, by trial and error (by using progressive increments of light to moderate exercise), the person could arrive at a walking, jogging, or cycling exercise level that produces this target heart rate. If the person wishes to increase training intensity to 85% of maximum, the exercise intensity must be increased to produce a heart rate of 153 beats per minute (0.85 x 180)
The use of swimming or cycling for aerobic rewards
[if sidelined with injury which does not allow weight bearing exercise – however it is first necessary to check with your medical advisor to see whether you are able to do any form of exercise]
Running versus swimming and other forms of upper body exercise. An adjustment must be made in estimating HRmax if swimming or other forms of upper body exercise are used for training. Maximum heart rate during these exercise modes averages about 13 beats per minute lower than while running for trained and untrained persons. This difference is probably the result of a smaller feed forward stimulation from the motor cortex to the medulla as well as less feedback stimulation from the smaller active upper body muscle mass. In swimming, the horizontal body position and cooling effect of the water also may contribute to a lower HRmax.
To establish the appropriate exercise intensity for swimming and upper body exercise, the difference of 13 beats per minute noted above should be subtracted from the age-predicted HRmax given in the image below. Consequently, a 30-yr-old person wishing to swim at 70% HRmax would select a swimming speed that produces a heart rate of 124 beats per minute [(0.70) x (190 – 13)]. This more accurately represents the appropriate threshold training heart rate for swimming. If this is not done, a prescription of upper body exercise based on a percentage of the HRmax during leg exercise results in an overestimation of the appropriate threshold training heart rate.
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Is less intense training effective?
The recommendation of using 70% HRmax as a training threshold for aerobic improvement should be viewed as a general guideline for establishing an effective, yet comfortable exercise level. This lower limit may depend on the participant’s initial exercise capacity and current state of fitness. In addition, older and less fit men and women may have training thresholds closer to 60% of HRmax, which corresponds to about 45% VO2max. Although 20 to 30 minutes of continuous exercise at the 70% level will stimulate a training effect, exercise at the lower intensity of 60% for 45 minutes will also prove beneficial. Generally, a lower exercise intensity can be offset by a longer exercise duration.
Reference: Exercise Physiology 4th Edition Pg 405 McArdle Katch Katch
Methods of Training
More training tips and sessions to follow
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