How does heart rate variability (HRV) react to heavy physical load (such as an hour of athletic activity)?
The HRV reacts in a highly sensitive manner to very different loads, especially to physical exertion. It decreases as the pulse rises („sympathicotonic condition“). Then it remains low until the body has largely recovered. This can last up to 24 hours (depending on the workload performed). If the HRV has still not normalized after this amount of time, this may indicate a „state of overtraining“. In this case, affected individuals usually feel tired and their condition worsens with additional training. Regular HRV measurements are therefore appropriate for recognizing a „state of overtraining“ relatively quickly and countering it with sufficient rest or adjustment of the training load.
Is the HRV subject to daily fluctuations?
Yes. A difference between day and night rhythms is especially apparent, with the influence of the sympathetic nervous system dominating during the day and that of the parasympathetic nervous system during the night. The HRV also fluctuates according to the stage of sleep, which has motivated some sleep researcher to classify sleep stages according to the HRV. Hormones also appear to be able to trigger fluctuations in the HRV over the course of a day.
How can disturbing influences (agitation, expectation) as evidenced by blood pressure measurements (high blood pressure in response to a doctor‘s examination, for instance) be avoided?
„White coat“ effects can be avoided by leaving the person to be examined alone for a few minutes. The recording works without a physician or other specialist needing to be present. If the person being examined still cannot relax, distraction tactics can be suggested (a few friendly words or even a short therapeutic discussion, 3 knee-bends, relaxing music, a slide show ...)
What medications can influence the HRV?
It is primarily the anticholinergic drugs that reduce the HRV (thus, antidepressants, for example). There is not yet a complete list.
Can more than one person use the same device (e.g. in one household)?
Clue medical can be used by more than one person (e.g. in one household). Before clue medical is passed on to a second user the memory should be deleted. Before passing on the device to other persons it is recommended to clean the device. How to delete the memory and how to properly clean the device please read the enclosed Operating Instructions.
Tachogram of the heart period
If, for each heart action μ within an established measurement period (e.g. 2 minutes with „clue medical“), the associated heart period TH(μ) (i.e. the respective RR-interval) is determined, and if this is applied as a function of the corresponding heart action, then a „tachogram of the heart period“ is obtained as a characteristic cardiovascular function. Such a representation therefore illustrates the fluctuations from heart beat to heart beat and therefore heart rate variability as well.
Heart rate variability (HRV)
Heart rate variability (HRV) is understood as fluctuations in heart rate from heart beat to heart beat over the established period of measurement. According to this, the heart beat is not normally even; instead, it fluctuates in a characteristic manner. The HRV is a parameter of the autonomic function of the heart as well as a measure of its regulatory capacity.