Training: Monitoring your recovery

Using heart rate variability to spot overtraining

Heart Rate Variability

Are you overtraining and would you spot it if you were? Neil Pedoe finds out about a new technology that takes the doubt out of how hard to ride.

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You’ll be forgiven for having never heard of heart rate variability, as the expensive cardiac equipment needed to test it was only previously accessible to a handful of top elite athletes and coaches.

But now recovery monitoring technology has made it to the training masses as an iPhone application called Ithlete. Is it really the holy grail of monitoring training recovery? And what is HRV anyway?

Rhythms of the heart

If you were told you had an irregular heart beat you might worry – but you shouldn’t, because it varies constantly as you breathe, speeding up as you inhale and slowing down as you exhale. It’s one of the many ways your nervous system keeps your body in equilibrium.

“Medicine has monitored and measured HRV for years, particularly during the treatment of patients with cardiac problems,” says Arizona-based coach and heart-rate training expert Dr Phil Maffetone. “Many of those patients’ problems are related to neurological imbalances – and likewise over-training will manifest itself in the same neurological imbalances and a similarly decreased HRV.”

So, while a greater HRV is a good indication of how healthy and rested you are, and how well you’re recovering from your training, a consistently suppressed HRV is a sure sign your body isn’t coping. More precisely, researchers have put this HRV depression down to an imbalance between the sympathetic and parasympathetic nervous systems.

The first is the system that regulates your body’s fight or flight reflex and how it responds to immediate stresses, while the second is the ‘rest and digest’ system. Physical and mental stress, illness and intensive training all cause an over-engagement of the sympathetic system, which in turn is reflected by a lower HRV.

This imbalance is immediate in response to stress and will last until your body has recovered from the stress it’s been subjected to. Which is, of course, how training works: it’s not the training that gets you fitter, it’s the training response during your recovery.

Testing, testing

As Dr Gavin Sandercock, lecturer in clinical cardiology at the University of Essex – and an Ironman competitor himself – points out, that’s the real advantage of using a daily HRV testing regime such as Ithlete: “Listening to your heart via HRV can not only stop you overtraining, but actually make your training more effective.”

That way you’re able to adapt your current day’s training load according to whether your HRV has returned to normal after the previous day’s exertions. Despite the complicated algorithms it claims to use for calculating your HRV, using ithlete is deceptively simple and only takes one minute every morning.

The same rules apply as when taking resting heart rate alone – so consistency is key and you should always take it at the same time, ideally before you even get out of bed. You’ll need the software as bought on iTunes, plus almost any standard analogue HR chest strap (there’s a list on the website), the iPhone ECG dongle that’s included in the price of the software, and the iPhone itself of course.

Once your HR strap has been detected, you simply press Start and copy the breathing of the virtual lungs on the screen. Sixty seconds later the software will have recorded a heart rate and HRV reading – just don’t forget that high HRV is good and low is bad.

As the software works by comparing your daily readings to a baseline, you’ll have to invest a few days ‘teaching’ the device before you can get much meaningful data out. But soon enough you’ll see a graph forming of your daily results with a traffic light colour coding of red, amber and green that tells you whether to rest, take it easy, or train as normal that day.

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Maffetone sings the praises of HRV monitoring to regulate training but predicts delays before it’s widely used and completely understood: “It’s not really technology that’s the problem but the speed with which athletes and coaches can learn to use them. The same was true with heart rate monitors when they came out. What’s more, the trouble with measuring HRV alone is it will tell you if you haven’t recovered from day-to-day but not why or what training you should do instead.”