<p>Yes. Several of the leading proponents of heart rate variability (Joel Jameson and a strength coach for a pro soccer team) hang out on Mike Boyle’s Stregthcoach.com forum where there have been lengthy discussions of HRV. Jameson sells a HRV app for iPhones (<a href=“http://www.bioforcehrv.com/”>http://www.bioforcehrv.com/</a>). The soccer coach, among other things, records HRV daily for all his players. It’s definitely a major fad in fitness circles.</p>
<p>1) For it it even maybe tell you anything useful, it’s got to be measured for several minutes while completely at rest – ideally first thing in the morning. In theory, decreasing variability indicates a state of over-training and “adrenal fatigue” (whatever that is). Increasing variability is theoretically a rested state, good to go for a hard workout.</p>
<p>2) My old Garmin could have HRV recording enabled and there’s a SportTracks plugin that records it , so I did a test for a month, recording a 5 minute segment first thing in the morning, sitting quietly, while waiting for the coffee to brew. It was a big waste of time. My HRV, based on geezer studies, is better than average and does not correlate with impeding cardiac doom, which is good. I already knew that from simple measures like heart rate recovery after max heart rate… But, as for day to day or week to week signals, HRV didn’t correlate with anything I was doing exercise-wise. Fir example, it didn’t show bupkis when I came home toasted from three days of camping and hiking. It it was readily apparent (to me) that I was toast after three consecutive days of testing, but the HRV testing didn’t show anything.</p>
<p>3) The guys who use it say that, at best “you have to interpret the results along with all kinds of other data, like how the athletes are feeling that day, etc.” To me, that’s just weaseling out. I don’t think the knowledge base is there.</p>
<p>4) If it’s useful at all (a big IF in my opinion), it seems to be a tool to convince crazy over-training athletes to take some easy rest days: MMA fighters and others who train obsessively at very high intensity. I don’t think a rational geezer fitness program should put you in that kind of overtrained state, with a mix of activities, some hard days, some easy days, some rest days.</p>
<p>5) IMO, they’ve taken a couple of small studies and extrapolated predictiveness and usefulness far, far, far beyond what is warranted. It’s probably a better prognosticator for heart attacks than athletic training. Most of the research that can be found online is in cardiology.</p>
<p>My new Garmin doesn’t have HRV enabled (it’s part of the Training Effects analysis that Garmin pitches with a couple of their running watches). It’s not a feature that I’m missing!</p>
</p>