Cardiac reserve in physiology
Cardiac reserve is the heart's ability to increase its blood output in one minute.
Compared to basal conditions, the human heart can increase its range of 3-7 times, in relation to age, health and degree of training. The maximum percentage increase in cardiac output (or output) compared to the values basal (at rest), constitutes the cardiac reserve.
Reserve heart rate according to Karvonen
The Karvonen method is concerned with indirectly calculating the ideal training heart rate or THR (target heart rate). Compared to the other indirect methods, that of the reserve heart rate is credited with the lower percentage of error.
Karvonen assumes that resting heart rate differs from individual to individual and uses this data to establish a new benchmark, called reserve heart rate. It then sets the subject's number of resting beats as zero, then calculates the training intensity percentage based on the difference between maximum heart rate and resting heart rate.
Heart reserve rate (HRR) = HRmax - HR rest
Therefore, in a 30-year-old male subject with a resting HR of 70 bpm, the theoretical cardiac reserve is equal to:
220 - 30 (age) - 70 (HR at rest) = 120 bpm
At this point the calculation of the range to control / maintain during training is estimated as follows:
(% Heart Rate Reserve) + Heart Rate resting heart
More generally:
THR = ((HRmax - HR at rest) ×% Intensity) + HR at rest
where is it:
% intensity = 60 - 70% for active or beginner recovery work
% intensity = 70 - 80% for aerobic work
% intensity = 80 - 90% for anaerobic work
One of the advantages of the reserve heart rate is that for moderate to high work intensity, the percentage value of HRR is similar to the heart rate corresponding to a "similar percentage of reserve of VO2max. Especially for a trained person, therefore, it represents a much more accurate reference than just a percentage of your maximum heart rate.
