I’ve been using the Android app BioForceHRV for just over a month now. That basically involves me taking a single HR reading almost every morning before I get out of bed and that reading takes about 3 minutes to take including putting the strap on. I have a Samsung S3 Android phone and I used a Polar H7 Bluetooth chest strap. Simple.
Turn the phone on, open the app choose the sensor, wait about 5 seconds for it to find the sensor. Press start and relax for about two and a half minutes. It chimes at the end and you save the result. Voila, a pretty graph like above appears.
You need to get a bit of history over a few weeks so that the software can get a baseline or normal reading for you. I haven’t had an extended rest period so the software might think my baseline is based on periods when I’m training in the above graph. I’m not too sure.
What does the graph show?
Well, from a training point of view it shows the end of a build/peak period, a taper to a race and the aftermath.
The lowest point on the yellow line is approximately race day. So you see before that day the other line is up and down and all over the place. I’ll come back to that.
Let’s start with the yellow line. That shows resting/waking heart rate. My MINIMUM HEART rate is in the mid 40s and you can see that my resting HR is consistently quite a bit above that by >5 bpm. That’s fine. But what the yellow line indisputedly shows is that once I start tapering it falls. If you look more closely (after you have read and understand about the other line) then you will see that the resting HR rises the day after a hard session.
You probably knew or suspected that already. And you know that you could quite easily take and record resting HRs. You could quite easily establish your own resting HR baseline with that information and use it to assess how recovered you are for a session when you wake up.
There are a lot of factors affecting your resting HR. So it’s good as a guide but there IS a more scientific way. Read on….
A bit about your heart
There is variability in how much your heart beats in any one period of time. As you breathe in and out; it changes. From one beat to the next; it subtly changes.
Heart Rate Variability = HRV = Often used synonymously with ‘R-R’
A self evident truth is that if you measure the time in between your heart beats; the time will obviously get less, the faster your heart beats. However, we are not talking about that, we are talking about the variability from one beat to the next.
The higher the variability the FITTER you are.
There are two nervous systems in your body. Basically one does speeding up stuff (heart & exercise muscles – the sympathetic nervous system) and the other does the slowing down and slow stuff (like digestion – the PARAsympathetic nervous system).
A bit about OVERtraining
Overtraining starts to materialise with an imbalance between your aerobic and anaerobic function/ability. You might see an increase in your resting HR and there are other symptoms such as emotional stress.
More serious overtraining may then go on to occur. This is SYMPATHETIC over-training typified by either; a high ANAEROBIC load; a HIGH trainingload; or lifestyle stress.
Even more serious overtraining would be to PARAsympathetic overtraining. Here you are stuffed. Exhaustion, aerobic deficiency. Abnormally LOW RESTING HR, high training HR and so on. If you are at this point you will know something is wrong. You ain’t gonna win anything if you are here.
So. You’ve probably never trained to that degree of wastefullness. But you most probably have had days where you couldn’t hit your normally achievable training targets. You know that during extended training periods you often feel tired. But how do you KNOW when tired is too tired? At that point you would make a micro-change to your schedule, perhaps missing out or delaying a particularly hard session.
Well. Going back to the pretty graphic. You can see a daily bar chart of your training readiness. With green being ready to go! Simple enough. It works. There’s science out there if you care to look for it. I now use HRV and feel a bit better for it.
I also temper the HRV information with the ‘time to recovery’ stat that is produced at the end of my session by my Garmin Fenix2. If I have just done a 6PM session and it says recovery is 26 hours and then the next day my HRV says MEDIUM – then I will do the next day’s session as the Garmin suggested ie late evening the following day rather than earlier.
Also look back to the original graph and at the red/orange/green changing line. Here HRV is re-based on a 0-100 scale, with 100 being super-excellent-elite-athlete. You will see my line declining as I come to the end of a hard peak period. As I taper it then goes a bit up-and-down, haywire!! I think large movements confuse the graph a bit and I think that I have not established, for the software, a proper baseline (which I think would be in the 80s if I was not training)
After the race I am having a few days off and you can see on the left hand side it tells me my current HRV load is LOW – fair enough!
But look before the race. There were a few warning signs there with the red line. Maybe I should have eased off? I felt pretty good in my triathlon race..until there was 3k left to run, at which point my legs were shot. Maybe I wouldn’t have had that had I eased off more in the peak period? It was only my C race so lessons were learnt.
Summary: This is a great way to augment looking at training through trainingload (TRIMPs). It seems to be a much more accurate indicator on a daily level. Trainingload is not able to help you taper well to a race and I don’t think that the HRV will either. BUT it will be a bit more accurate on a granular, daily basis. HRV training will also help you if you plan your own sessions – if you make mistakes it will tell you to ease off the training soon enough. Also I think that over the last few years I maybe have pushed it too much, HRV is already making me temper my training. I’ve yet to see how that pans out with race results or PBs. We’ll see.