Cardiorespiratory endurance may be improved through a number of different methods. Largely, the amount of improvement possible will be determined by initial levels of cardiorespiratory endurance. Continuous training involves four considerations:
1) Mode
The type of activity used in continuous training must be aerobic. Aerobic activities are those that elevate the heart rate and maintain it at that level for an extended time. Aerobic activities generally involve repetitive, whole - body, large muscle movements performed over an extended time. Examples of aerobic activities are running, jogging, walking, cycling, swimming, rope skipping, stair climbing, and cross - country skiing. The advantage of these aerobic activities as opposed to more intermittent activities, such as racquetball, squash, basketball or tennis, is that aerobic activities are easy to regulate by either speeding up or slowing down the pace. Because we already know that the given intensity of the workload elicits a given heart rate, these aerobic activities allow us to maintain heart rate at a specified or target level. Intermittent activities involve variable speeds and intensities that cause the heart rate to fluctuate considerably. Although these intermittent activities improve cardiorespiratory endurance, they are much more difficult to monitor in terms of intensity.
2) Frequency
To see at least minimal improvement in cardiorespiratory endurance, it is necessary for the average person to engage in no less than three sessions per week. If possible, one should aim for four or five sessions per week. A competitive athlete should be prepared to train as often as six times per week. Everyone should take off at least 1 day per week to allow for both psychological and physiological rest.
3) Duration
For minimal improvement to occur, an individual must participate in at least 20 minutes of continuous activity with the heart rate elevated to its working level. Recent evidence suggests that even shorter exercise bouts of as little as 12 minutes may be sufficient to show improvement. Generally, the greater the duration of the workout, the greater the improvement in cardiorespiratory endurance. The competitive athlete should train for at least 45 minutes with the heart rate elevated to training levels.
Of the four factors being considered, the most critical factor is the intensity of training, even though recommendations regarding training intensities vary. Hiis is particularly true in the early stages of training, when the body is forced to make a lot of adjustments to increase workload demands.
Because heart rate is linearly related to the intensity of the exercise and to the rate of oxygen consumption, it becomes a relatively simple process to identify a specific workload (pace) that will make the heart rate plateau at the desired level. By monitoring heart rate, we know whether the pace is too fast or too slow to get heart rate into a target range.
Several formulas identify a target training heart rate. Exact determination of maxireal heart rate involves exercising an individual at a maximal level and monitoring the heart rate using an electrocardiogram. This is a difficult process outside a laboratory. However, an approximate estimate of maximal heart rate for both males and females is that maximal heart rate is thought to be about 220 beats per minute. Maxima heart rate is related to age. As age increases, maximal heart rate decreases. Thus a relatively simple estimation of maximal heart rate (HR) would be Maximal HR = 220 - Age. If an athlete is working at 70% of maximal rate, the target heart rate can be calculated by multiplying 0.7 ( 220 - Age).
Regardless of the formula used, it should be clear that to see minimal improvement in cardiorespiratory endurance, the heart rate should be elevated to at least 70% of its maximal rate. In a trained individual it is not difficult to sustain a heart rate at the 85% level.
