Over the past decade or so, there has been some very interesting advancements in our ability to predict ones adaptation potential to endurance training. Heart rate variability (HRV), a measure of cardiovascular-autonomic function, appears to be a strong indicator of one’s adaptation capacity. For example, baseline HRV has previously been shown to correlate well with changes in markers of aerobic fitness following a training program. These findings lead to an experimental protocol by Kiviniemi et al. (2007) that compared HRV-guided training verses pre-planned training in healthy, recreational runners. Essentially, subjects in the HRV-guided training group would train with greater intensity when their HRV was within or above baseline values and would have a low intensity session or complete rest when HRV was below baseline. The results of this study showed that members of the HRV-guided training group improved fitness markers to a greater extent than the pre-planned training group.
A new study published ahead of print in the Scandinavian Journal of Medicine and Science in Sports by Vesterinen et al. (2015) aimed to determine if HRV values can provide information regarding appropriate exercise prescription. Baseline HRV and fitness values were acquired from 37 recreationally trained endurance athletes. An 8 week preparatory period had the subjects perform a standardized training program before a subsequent 8-week experimental training program. For the experimental program, the subjects were matched based on fitness and HRV and evenly divided into a high volume training group and a high intensity training group. The high volume training group trained at moderate intensities, but increased overall volume by ~35% compared to the preparatory period. The high intensity group did not increase their overall volume or work, but did increase the amount of high intensity work.
The results were very interesting. A significant negative correlation (r = -0.74) was found between baseline HRV and changes in fitness in the high volume group, indicating that subjects with low HRV responded well to this type of training while those with high HRV in this group did not respond well to this training. A significant positive correlation (r = 0.63) was found between baseline HRV and changes in fitness in the high intensity group. Here, subjects with high HRV responded best to this type of training while subjects with low HRV responded poorly. These novel findings suggest that baseline HRV may serve as a good marker for determining exercise prescription (high intensity training verses moderate intensity with higher volume) for improving fitness markers.
Kiviniemi, A. M., Hautala, A. J., Kinnunen, H., & Tulppo, M. P. (2007). Endurance training guided individually by daily heart rate variability measurements. European Journal of Applied Physiology, 101(6), 743-751.
Vesterinen, V., Häkkinen, K., Laine, T., Hynynen, E., Mikkola, J., & Nummela, A. (2015). Predictors of individual adaptation to high‐volume or high‐intensity endurance training in recreational endurance runners. Scandinavian Journal of Medicine & Science in Sports.