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HRV DFA alpha 1

I wrote some python code to do some analysis of my Heart Rate Variability - HRV. Why is HRV interesting? Well the theory is that microvariations in heart rate increase as your work rate increases.

So I did a ride in largely Z1-3 today and this is the plot of HR and DFA Alpha 1

well that isn't too useful but you see that DFA Alpha 1 is inversely proportional to HR. In other words the harder you ride the greater the beat variability.

It has been claimed that a figure of 0.75 is the lactate threshold. so Zooming in on the climb at 1300 seconds this seems to be 162bmp - rather high as my HRmax is 185bmp and normally we'd expect this to be around 80% of HRMax, so more like 148bmp.

Why is this interesting? Well polarized training suggests doing 80 % of your rides under the lactate threshold HR. There is a minor industry that has grown up building apps that estimate lactate threshold.

This is another snapshot. We see that when the blue line cross 0.75 the HR is around 145 which is more in the ball park.

and to finish a plot of DFA Alpha 1 against HR. It looks a bit of a mess tbh but if you were to plot a center trend line it would show an inverse relationship between HR and HRV and the 0.75 point would be somewhere around 145bpm.

I don't know if any of this is interesting or actually useful or even if the data can be interpreted. If anyone is interested in the code it is some python scripts which use the DFA routine from Marco Altini.

Just to point out, my ride isn't the kind of protocol that is used in this kind of exercise. Normally you'd be expected to do a ramp test with 10bmp jumps in hr every 2-3 minutes. I'll try giving that a go.

BASI Nordic Ski Instructor


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