Heart Rate Variability maps the road to recovery

I am on the road to recovery from the debilitating illness that had incapacitated me for 4 weeks. The two charts below show the Poincare plots of R-R intervals recorded using my Polar RS800cx during 5 minutes of relaxed deep breathing while sitting, on 12th July (3 days after the resolution of symptoms) and on 18th July (9 days after resolution of symptoms).

Poincare12-18July2009

The much greater scatter of points on 18th July demonstrates that I am now far less stressed. On 12th July mean heart rate while sitting was 60 bpm while it had decreased to 54 bpm by 18th. Even more dramatically, the overall standard deviation, which provides an indication of the overall amount of variability in heart rate, had increased from 40.1 milliseconds to 82.9 milliseconds. The standard deviation in the direction at right angles to the 45 degree line (which provides an indication of the amount of parasympathetic activity) increased from 23.8 milliseconds to 56.4 milliseconds. These numbers reveals that the variability of my heart rate had more than doubled over the six day period. The increase is due to an increase on both parasympathetic activity (which is associated with relaxation and recovery) and also an increase in variability of sympathetic activity.

I had done some easy running on 10th and 11th July, and since 12th, I have done a further 3 sessions, on each occasion running 5Km in the lower aerobic zone.

Overall, these observations are very encouraging. However, I have lost a great deal of fitness during the four weeks of illness. Today, during an easy 5Km run, I recorded 722 heart beats per Km, whereas I was recording values around 650-680 beats per Km when running at a similar pace before I became ill. Although the degree of variability is similar to that before I became ill, my average heart rate of 54 bpm when sitting today was still somewhat higher than the 46 bpm recorded prior to my illness. I think these data should be interpreted as evidence that my stress levels are back to near the pre-illness levels, but my aerobic fitness is substantially reduced. Nonetheless, the recovery of my heart rate variability suggests that I am now sufficiently recovered to resume regular training.

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3 Responses to “Heart Rate Variability maps the road to recovery”

  1. Ewen Says:

    That’s quite a dramatic improvement. It’s going to be interesting to see how the plots change once you commence regular training (and how quickly the beats per km return to normal.

    I agree with your comment on my post about the possible usefulness of HRV readings for predicting overtraining. The trouble with the RS scale, is that one can see the pattern after the event. I’m also interested in using it to guide the number of easy days between hard days.

    It sounds like Polar have improved the footpod – if so, it could be useful in big city races (for me) where the Garmin plays up because of tall buildings.

  2. Todd Says:

    I’m a 43 yr old runner recovering from a heart attack/heart surgery and want to graph my hearts recovery from past & present records from my Polar RS800cx. Could you help with infromation on how you graphed your data shown in this post?

    • canute1 Says:

      Todd. The easiest thing to do is to use the Polar ProTrainer software to create the Poincare plot. (Note that Polar simply calls it a scattergram). Select a segment of the HR trace that is about 2 minutes in length (during which you level of activity was constant – eg resting); and then select scattergram within the view menu. This will create the Poincare plot. You might need to adjust the properties of the display to ensure that the range of R-R values fits within the field of view.

      To produce a plot in which I could easily adjust the display for presentation in my blog, I exported the r-r data into a text file (using export as text command in the file menu); loaded the text into excel, created two adjacent columns displaced by one R-R interval such that the 1st R-R interval in column one was beside the 2nd R-R interval in column two, and then created a scatter plot of the two columns (with the nth R-R on one axis and n+1st R-R on the other. However, unless you want to manipulate the display for optimal visual display, I suggest you let Polar Protrainer create the scattergram.

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