The ability of the human organism to withstand physical strain is one of the most important characteristics of health. We can easily distinguish a person who is able to run 10 miles from an individual that can't even walk 100 yards without a break. The difference between them is in their physical fitness. But what is "physical fitness"? According to physiology it is first of all the ability of the cardio vascular system to provide the function of the organism in the state of heightened strain. Therefore, in assessing the state of the cardio vascular system we are also assessing the state of physical fitness. In recent times, for this purpose, the method of analyzing heart rate variability during the orthostatic challenge test became widely used.
Heart Rate Variability It is well‐known that orthostatic challenge test is one of the most informative methods used to detect subtle changes in cardiovascular function and specifically its regulatory mechanisms. When body's position is changed from supine or sitting to standing, specific changes in heart rate and blood pressure happen as a compensatory reaction of the body. This standup maneuver as well as keeping a standing posture within several minutes does not cause any significant physical exertion to a healthy individual. However if body's regulatory mechanisms do not have adequate functional capacity or there is subtle cardiovascular deficiency then this maneuver becomes a significant stressor to the body.
With the help of heart rate variability analysis it is possible to asses these regulatory mechanism. During the standup maneuver in the first 10-15 seconds after standing up the frequency of heart beats increases from the fall in blood pressure due to gravitational redistribution of the blood mass. Then the cardiovascular system attempts to compensate an orthostatic effect of standing up by constricting peripheral blood vessels. As a result blood pressure returns to its normal level and heart rate drops. Multiple research studies have shown that reaction of the cardiovascular system on changing body posture and speed of its compensation depends on fitness level. The most indicative parameter of this Heart Rate Variability test is a pattern of heart rate changes caused by a standup maneuver. The weaker and slower this reaction is the less an organism is fit and susceptible to physical exertions, which means lower level of fitness.
Modern techniques of HRV (Heart Rate Variability) analysis allow us to determine an almost exact cardiovascular function condition during the orthostatic challenge test. For example, the Heart Rhythm Scanner program, developed by Biocom Technologies, includes Cardiovascular Health Test. It makes an assessment of the cardiovascular function condition based on two variables:
Cardiovascular Tolerance - indicates dynamic regulatory reserve of the cardiovascular system responsible for a quick reaction to rapid changes in the body's condition.
Cardiovascular Adaptation - indicates the ability of the cardiovascular system to adapt to physiological changes in the body and establish a new stable regulatory state.
The higher the variables of these results the better the ability of the organism to withstand physical strain and as a result a higher level of fitness.
Heart Rate Variability is a powerful, very accurate, reliable, reproducible, yet simple method of fitness assessment. Regardless of the vast amount of research in this field, its use by fitness specialists has not yet spread to reach full potential. However, the use of this method will give an individual the ability to customize his physical strain according to cardiovascular function. This will help to avoid overstrain of the organism during workout. The Heart Rhythm Scanner can make any workout more effective.