True / False: The use of heart rate variability (HRV) allows practitioners to examine the influence of the nervous system upon the body and upon recovery. Greater variance in the R-R intervals indicates stronger influence of the parasympathetic nervous system (select one word answer only please).

Answer;

Explanation:

If it is possible to  measure the  time intervals  between consecutive heart beat in milliseconds, and determine how the time intervals varies from time to time, then the value obtained is called Heart Rate Variability. It can be  felt when pulse at the wrist is measured and  deep breath taken and exhale afterwards.

Longer interval is observed during exhalation when the HR is long thus the  heart slows down,while short intervals during fast beat of the heart,with fast HR.It can be detected by ECG through measurement of intervals between R waves( R-R).

HRV is regulated by ANS, through the sympathetic , which increases the heartbeat and therefore reduces the  HRV, and the parasympathetic which reduces the heart beat and therefore increases the HRV, since  the slower beats enabled  easy measurements of  intervals between  consecutive heartbeats.

Therefore,  the variance  in  the R-R waves intervals is determined by the parasympathetic nervous system which slow the heart beats for  higher HRV values to be obtained.The answer is TRUE

the second one is wrong

explanation: