More thoughts about HRV-guided training

After yesterdays’ post on HRV guided-training, in which I discussed the two studies by Kiviniemi and colleagues [1,2], I realized that what I had written might give the impression that I undervalue the findings of those studies.  Although I do not consider that those studies provide convincing evidence about the practical value of HRV-guided training, I do consider that they provide some very thought-provoking findings.  To me the crucial point in both studies is that they demonstrate that for recreational athletes, doing more than three intense sessions per week is likely to result in over-reaching. 

In the first study, the participants were club runners.  In the second study they were moderately active individuals doing about 2 exercise sessions per week.   In both studies, the intense sessions included 30 minutes of tempo running at 85% of HRmax.  In both studies, scheduled intense sessions were replaced by low intensity sessions or rest if there was a moderate decrease in HRV measured in the morning.  In both studies, the control group following the fixed training schedule did at least one more intense session per week than the HRV-guided group, implying that a decrease in HRV exceeding the threshold dictating abandonment of an intense session occurred at least once per week.   Furthermore, abandoning at least one high intensity session per week was associated with significantly greater improvement in performance by the end of the study

In the first study, the control group performed four high intensity sessions per week while in the second study the control group performed an average of 3.3 high intensity sessions per week  These studies provide clear scientific confirmation of a fact that many athletes and coaches have discovered through experience: doing more than three high intensity sessions per week  is counterproductive.  In the case of frequent intense sessions, more pain does not usually produce more gain.

The narrow gap between Scylla and Charybdis

A further conclusion that can be drawn from these studies is that even for recreational runners there is a fairly narrow gap between the training load that is required for worthwhile improvement in performance, and the training load that results in over-reaching.  Because most recreational athletes do not have an experienced coach to steer them between Scylla and Charybdis (the mythical sea monsters on opposing rocky shores, threatening to wreck hopes from either side) each individual needs to work out a satisfactory way of judging for themselves how intensely to train. 

What do we hear when we listen to the body.

One approach is simply to ‘listen to the body’; reduce intensity whenever the body complains; and rest whenever the level of fatigue becomes excessive.  The problem with this approach is that it is very difficult to decide what level of fatigue indicates significant over-reaching.  It is not uncommon to experience sluggishness during the early part of a training session and then fell lively later in the session.  If we rest whenever we feel moderate fatigue we are unlikely to achieve our full potential. 

Another approach is to include an easy week in the schedule every fourth or fifth week.  In general, this can be a fairly successful strategy, and is included in many recommended training schedules. However, there is little evidence to guide an individual regarding to the adjustment in load that is best for him or her.  Optimizing training for the individual requires knowledge abut the individual’s own response to training.  

The message from the heart

My own experience, particularly in the period following my episode of illness last summer, is that measurements of heart rate and heart rate variability do provide a useful guide in deciding whether feelings of fatigue indicate significant over-reaching.  However, I am still undecided as to which measurements are most informative.   Last August, I found that the decrease in the magnitude of the heart rate rise during an orthostatic test was the most reliable guide (as discussed in yesterday’s post).  However, at that time I was suffering from parasympathetic over-reaching. 

The studies by Kiviniemi and colleagues suggest that even the early phases of sympathetic overreaching are associated with diminished benefit from training.  Therefore, I am still eager to explore the possibility that HRV might be a practical guide to adjusting training intensity.  While I do not think the studies by Kiviniemi provide convincing evidence, I think the evidence that they do provide is encouraging.

References

[1] Antti Kiviniemi, Arto Hautala, hannu Kinnunen & Mikko Tulppo (2007) Endurance training guided individually by daily heart rate variability measurements. Eur J Appl Physiol. 101(6):743-751.

[2] Kiviniemi AM, Hautala AJ, Kinnunen H, Nissilä J, Virtanen P, Karjalainen J, Tulppo MP . (2010) Daily exercise prescription based on Heart Rate Variability among men and women. Med Sci Sports Exerc. 42(7):1355-63

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2 Responses to “More thoughts about HRV-guided training”

  1. Jim Manley Says:

    I am very glad you are writing about this. I’ve followed your HRV postings carefully and have tracked mine through Polar’s OwnOptimizer test on my 810. I have found them of some use, but remain unconvinced that they are the key I thought they might be. In particular, I have had many erroneous readings — some of which I didn’t recognize to be so at the time. There is a “9” or “parasympathetic overtraining” flag which I have often got because of unchanged stats. But in fact I was not overtraining — if anything, the reverse — at least on some occasions. I kept training via the same routine (about 100 miles of biking a week, plus some crosstraining — I’m 68) and the greens (1′ and 2’s — “Recovered” and “Normal Training”) started popping up again. Better to listen to the body. But if you selectively discount the readings, this diminishes HRV as the criterian of recovery in training. Best, Jim

    PS The blog I identified is one about controlling cholesterol, one part of which is exercise, one indicator of — HRV

  2. Ewen Says:

    Canute, the ‘listen to your body’ advice is great, but as you say, reading those signals isn’t easy. That’s a skill I’ve yet to perfect, even after almost 30 years of pretty much continuous training.

    I like the idea of a ‘down week’ every third or fourth week. I also think 2 or 3 ‘hard’ sessions per week is all that’s needed. You also make the good point that we may not reach our potential if we are too conservative when ‘listening to our bodies.’

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