There's an App for that!

One of my favorite readers, Heather, asked a very good question about the slogging of marathon training. Instead of responding in a comment, I decided to write a post instead. Here's her question:

"how much fatigue and slogging is an acceptable level for you? Or do you not feel sloggy that often, but simply a bit tired? I have a really hard time determining if I should push through sloggy dead legged phases, or back off before I overreach/overtrain. You've written about being a fan of large amounts of running data, do you use that data to determine if you're recovering properly? Is there an app for that?"

There IS an app for that! I use it every day, and it's called ithlete. This is an app that, coupled with a bluetooth heart rate monitor, measures your heart rate variability (HRV). I've posted briefly about it before, but I wanted to spend a bit more time with it since I have really begun to rely on it as a training tool. I have also been reading more and more research about what an impressive measure HRV is for a number of different things in addition to training.

First off, there are a lot of apps that measure HRV. At one point, I was trying to evaluate a few of them simultaneously which required taking my HRV using 3-4 different apps every morning and that was really not tenable. I quickly zeroed in on ithlete because of the ease of use, the user interface and mostly because of the fact that it interprets the data in a way that I can use. Having an HRV number was really not very helpful for me. Let me show you what I mean.

You'll want to click on the image so you can get a closer look, but what you see here is my HRV data for the past 9 months or so. The green, yellow and red dots connected by the light blue line at the top of the chart are the daily HRV values. You can see I took a break in August. The black bars are showing my training intensity. I enter that data for my workouts basically scoring them from easiest (1) to hardest (9). The red dots in the middle of the chart are my resting heart rate values. I mentioned in a previous post how my resting HR had gone down over the past year and this really shows that drop nicely. Here's a closer look at my HRV for this marathon cycle.

You might notice a pattern in this chart of a drop in HRV (usually shown as a red or yellow dot) after a hard workout (tall black bar) followed by a rebound back to the pre-workout value. This is what you want to see. Also notice that there are a lot of other things I could add to this chart (sleep, fatigue, soreness, etc.). These are qualitative ratings you input every time you take your HRV. The idea is that you can look for correlations between HRV and these factors. It can get kind of messy, so I usually just use training load. One really interesting thing to note, for those of you who use resting heart rate as an indicator of fatigue and overtraining is that it is really not very sensitive. My HRV is scooting all over the place in response to training, sleep, and life stress but my RHR is staying pretty darn steady. It makes me wonder if RHR is really a good measure for telling you when you've gone over the edge, but it can't really help you know when you're getting close to the edge. This may be peculiar to me, but worth a few thoughts.

These charts shown above are screenshots from their website but are also included in the app. 

What I find the most useful for day-to-day decision making is this chart, which is only available on their website and you have to have a "pro" subscription ($5/month) to get access.

It plots your daily recovery and activation to give you an idea how recovered you are and how much energy you have. It plots these data on the chart based on your values from the last 30 days. It also gives recommendations for training that day. I almost never act on the low activation recommendation. I find it correlates strongly with a low RHR and I think my RHR is falling due to training and not necessarily because I am burning out. I do act on the high activation data. I have found that higher activation levels occur when I am stressed out. If that is coupled with a low recovery, I generally take an extra recovery day. With the higher volume training I am doing right now, I find I am needing more recovery between workouts in general (3 days rather than 2). The timeline chart actually shows that really nicely with the interval of tall and short bars. 

One thing I would like you to take away from this post is that recovery is your best friend. It isn't a necessary evil. You should love your recovery days. Marathoner Kim Jones, drove this point home for me during a podcast interview on Runner's Connect. Kim Jones obviously had a lot of talent, but she also was super smart about her training. She said she loved her recovery days and when Benji Durdan, her coach, told her to take another recovery day instead of doing a hard workout she really looked forward to it. She said she knew that those days were the days that allowed her body to absorb the training and that's why she loved them. She said she just didn't understand why athletes were so against taking recovery days, so much so that they might even hide how they were feeling from their coach out of fear that they might have to skip a workout. Your body can only absorb so much work.

So, back to Heather's question: I use the daily HRV readings to help make decisions about my training and adjust on the fly. I have a general (slightly ambitious) schedule, but I made a pact with myself when I wrote it that I would be a good self coach and move stuff around based on how I felt and what the HRV data said. I am prioritizing high volume right now, so I am just embracing the tired leg feeling I have most days. My workouts are at slower paces than I would typically run and I am at peace with that too. I am not tapering for races but am instead using them as opportunities to get used to running on tired legs. 

When would I back off? If I saw that my HRV values were remaining low for multiple days without recovering or the overall average was dropping precipitously, I would take some down time. The blue line in the middle chart is the average HRV value and while it is slightly lower than a couple of months ago, it's going up and down just fine for now. I am still 7 weeks out from CIM, so it will be interesting to see what happens to it. 

Obviously, you don't need this app and the website to help you figure out when to back off, but I like having a little corroboration when I am feeling tired in training. I find that some days I will have a sloggy running day with a high HRV value or a good run with a relatively low HRV value. It's really more about the trend over time and being able to manage training so you don't push yourself over the edge. I find having this data really helps me. The other useful application is in trying out new training tools like supplements or adding more sleep to your routine, etc. You can see whether your recovery is enhanced by these new things after you start using them. I'm doing that right now with some new supplements that were recommended by a former coach (and elite masters runner). I am excited to see whether I am able to fit in more training while keeping my HRV steady over the next 7 weeks.    

One last thought: I have found that life stress, lack of sleep and strength training can have pretty large effects on my HRV values, even more so than my running. So, I would have to back off of my running training if one of those factors caused my HRV to plummet.

Thanks for the comment, Heather! I hope I answered your questions:)