Who, why and what?
We have known for a long time that aerobic exercise increases heart rate variability (HRV) when performed regularly, but a new paper on a study performed by experienced French & Australian researchers, Chalencon et al., set out to look in more detail at the relationship between training load, performance and HRV. Importantly, they were trying to build a model that would allow elite swimmers’ performance to be predicted from training load and HRV (indicating both recovery and aerobic development). Data were gathered from the 10 swimmers weekly over a period of more than a year, including HRV measurements before performing a 400m time trial assessment.
What did they find?
When individual HF HRV data were plotted against individual performance data, a highly significant relationship appeared for all of the 10 subjects, R² values ranged from 0.55 to 0.80 (p<0.001). This is shown graphically in the chart below:
In fact, the relation they found was so strong that they concluded using performance or HRV as the systems (model) output provided the same information on the impact of training on the fatigue and adaptation status of the athlete.
The effectiveness of the model can be seen in the chart below, where the training load chart over a 30 week period is repeated to allow comparison between the achieved performance, modelled performance, measured HRV and predicted HRV:
The conclusions I took from this study are:
Taper periods need to be quite long (2-3 weeks) in order for adaptations to really take hold. For an individual using ithlete to measure HRV, this could mean continuing the taper until no further rises in HRV are seen before starting to ramp up the next training block. Conversely, if HRV is not decreasing during an intensive training block – you’re not working hard enough.
There is no significant difference between genders in the model, implying that HRV based training is equally applicable for men and women.
It’s not the athlete with the highest HRV that wins, it’s the athlete that manages to increase their HRV the most that gets the biggest gains in performance.
Anyone can repeat this study for themselves by doing regular performance tests in their sport and seeing how well their daily (or baseline) HRV correlates. We’d be really interested in hearing from anyone that has done this!
To read the HRV research paper
Chalencon S, Busso T, Lacour J-R, Garet M, Pichot V, et al. (2012) A Model for the Training Effects in Swimming Demonstrates a Strong Relationship between Parasympathetic Activity, Performance and Index of Fatigue. PLoS ONE 7(12): e52636. doi:10.1371/journal.pone.0052636