5 months with iThlete — tracking recovery through HRV

When I first learned about iThlete, I was extremely excited to get one.  I knew several NFL teams were using an HRV (Heart Rate Variability) system called Omegawave, but Omegawave was way out of my price range, costing thousands of dollars.  iThlete, built on some of the same science, was less than $100 with app, dongle, and chest strap (cheaper if you have the strap already).  Now that’s more like it!

So, what is HRV and why is it important?  Well, HRV is a way to test your current fatigue, but more specifically your CNS (Central Nervous System) fatigue.  An HRV test measures the time between your heart’s beats.  When rested, the time between heart beats will vary efficiently based on your breathing.  Your CNS regulates beats so that your heart beats more rapidly when inhaling (new supply of O2) and less rapidly when exhaling.  However, when your CNS is fatigued (like after a hard workout), your “heart beat efficiency” drops and times between beats are more regular (a little counter intuitive at first — I originally equated consistent beats with recovered — but your body is smarter than that).

The CNS and PNS (peripheral nervous system) controls everything about how we move.  Every stride is a complex loop of sensory input and coordinated motor unit firing.  Thus, understanding how your CNS is taxed and how long and well it responds to being stressed (via workouts) can greatly greatly benefit the athlete and coach.  A low HRV score means your CNS is suffering and working sub-optimally.  And thus your chance of injury is higher, especially if your workout calls for a taxing CNS regiment (e.g. maximal velocity sprints, heavy deadlifting…).  A high HRV score means you are primed for a good workout from a CNS perspective.

Think about it this way: A low HRV score means you are going to be less coordinated.  I don’t mean coordinated like rub you tummy while patting your head.  I mean motor units firing in synchronized and successive order to make accurate and powerful movements.

At least, that’s the theory.  My experiences weren’t perfect, but they were very good.

iThlete — the app

iThlete is an app for the iPhone and Android devices.  I downloaded it on Jun 5, 2012 and have used it “almost” every day since.  The instructions are straightforward. Put on your chest strap, plug in the dongle (dongle-less bluetooth version coming soon), let the app sync (waits for your heart beat to stabilize) and then breath with the animated lungs on the screen.  All-in-all, it takes about 90 seconds from grabbing your iPhone to having a reading.

The app has three tabs: one for measuring your HRV, one for viewing a graphical chart of your results, and another to display and edit a list of results.  The edit allows you to input your workouts level of effort for any given day (0-10 scale).  Overall, the app is nice, clean and simple.  A couple changes I’d like to see (like better interaction with the charts), but nothing major.

Warning: when I first starting using the app, I got some pretty erratic readings.  I’d test myself, then retest, then retest again…just to confirm the readings.  What I got was massive differences from one reading to the next — once going from 60 to 100.  The user guide suggests taking your measurement first thing in the morning while standing.  The reason for this is that standing increases your heart rate slightly, compared to sitting, and thus variations are easier to detect.  However, I found that sitting in the exact same relaxed position every morning yielded more consistent results.  Immediately, my HRV reading began to stabilize from one test to the next and only fluctuate greatly from one day to the next (based on my workouts).  While sitting my personal range is typically between 65 and 85.  A reading under 70 means I’m vary fatigued.  A reading about 80 means I’m primed for a good workout.  In late August, I started doing my test standing up.  Happily, my test-to-test samples were now very consistent.  I believe those early erratic tests were due to nerves and over-interest in the product.  Now, in the standing position, my reading are from slightly less than 60 to low 70s.

Here’s a video from iThlete describing the features in version 2. This gives you a great idea of what you can expect.

Also, here’s a link to my personally readings: ithleteHRV.xls

The Promise

Here’s a copy/paste from the iThlete user manual.  Sounds pretty amazing!

• Objectively measure your body’s response to each workout
• Improve performance without risk of injury or illness
• Decide when and how hard to train
• Optimize your recovery
• Receive early warnings to help avoid overtraining
• Perfect your taper period before big races
• Track long-term changes in your aerobic fitness
• Enjoy rest days without feeling guilty
• Receiver works with most heart rate monitor chest straps

My Experience

I started using iThlete with the approach of 1) working out, then 2) wait for my HRV to return and then 3) workout again.  This worked in a way.  But I really didn’t have a “base” for understanding my reading.  So, the result was that I was working out then skipping 1-2 days every time.  Never did my HRV go sideways and let me workout two days in a row.  This didn’t seem right.  I know I’m 42 years old (now 43), so my recovery is going to be slower than in my prime.  But I felt as if I still needed to be working out more.  One side effect from skipping 1-2 days every time is that my average HRV (a trailing average of the last 20 days, I believe) made a slow steady ascension from around 69 to  79, with peak HRV readings of about 90.  A reading of 90 is really high.  In general, the readings aren’t bracketed between 0 and 100, but from my understanding a reading above 100 is pretty rare.  It suddenly dawned on my that my HRV average could not continue to climb — it had to level out.  What I had been doing is training with the focus on raising my average HRV…which is really just controlling your CNS excitability– or tapering.

So, I adjusted my thinking.  In reviewing the data, it “appeared” that certain workouts had more effect on my CNS then others.  I already knew this in theory, but it was interesting to see in action.  One example that surprised me was when I first threw the shot put.  I hadn’t thrown shot for 18 years, so I took it really easy.  I just did a few over-the-head throws and some standing throws.  I also did a light running workout.  Much to my surprise, my CNS fell through the floor.

With this new knowledge, I reassessed my workout planning.  Categorically, my Anaerobic Speed days were more taxing then my Anaerobic Fatigue days, which of course makes sense.  So, with the belief that it is more important to be fully rested on my Anaerobic Speed days, I chose to design my week as:

M: Anaerobic Speed (high CNS)
T: Anaerobic Fatigue (low CNS)
W: Active rest
Th: Anaerobic Speed (high CNS)
F: Anaerobic Fatigue (low CNS)
S/S: Active rest

I also opted to do more the CNS taxing lifts (deadlift and cleans) on M and Th, before my CNS was too depressed   With this schedule, iThlete confirmed that the combined M/T and Th/F block would depress my CNS enough that I needed a day off.  Biologically, I could probably take just Saturday off, but that doesn’t work too well with a 7 day week.

However, not everything was roses.  Three times during these months I strained my hamstring (twice on right, once on left).  This is above and beyond the minor tweaks that I got throughout the months; these were true “strains”.  On each of these occasions my CNS measurement was high, so I thought I was safe.  At the same time, on each of these days, I could have ascertained the danger had I just used my brain.  Two of the times came the day after a long drive (6-plus hours).  The third came in any early hurdling session, when I was pushing too hard too soon (my hamstring warned me with knots that I ignored).

Scorecard

How did the claims stack up?

• Objectively measure your body’s response to each workout — Yes
• Improve performance without risk of injury or illness — Not totally.  A bit of an exaggeration.  Definitely a warning system, but you need to use your common sense, too.
• Decide when and how hard to train — Yes
• Optimize your recovery — Yes
• Receive early warnings to help avoid overtraining — Yes
• Perfect your taper period before big races — Maybe, but it appears so
• Track long-term changes in your aerobic fitness — I don’t train aerobic, so no comment
• Enjoy rest days without feeling guilty — Yes
• Receiver works with most heart rate monitor chest straps — I assume

Final Thoughts

iThlete is a great tool.  It definitely helped me create the weekly plan that I now follow.  It also gives me insight into which workouts were especially CNS taxing and which perhaps I took too lightly.  While it won’t catch every possible injury scenario, it does give you an early warning system into CNS fatigue related ones and into over training syndrome.  Learn more by visiting www.myithlete.com