There is an old adage among serious athletes: Never stand if you can lean, never lean if you can sit, and never sit if you can lie down. Joe Friel, The Triathlete's Training Bible, 4th. ed., pg 175.
Lately I have more days when I feel really tired than in the past. That makes sense when you consider that I am basing my marathon training on a slightly modified Ironman training plan. A plan, by the way, that does not take into account my being a really old guy -- in March I'll make it into the 70+ age group. The modifications are mostly a reduction in swim distance, which means my legs are getting a lot of work. Just what is required for a marathon ... but is it too much?
Chapter 11 of Friel's book is titled Rest and Recovery. In it he presents a convincing case for the need to get plenty of rest, and, just as important, to keep in mind that the stress we need to recover from includes all sources, not just the stress from workouts. Career, family, relationships, and finances are just a few potential sources of stress. One point he omits is that physical activity can offset some of the effects of mental stress. I guess the way to look at it is that emotional stress drags you down and physical stress does too, but physical stress enhances sleep, and it is sound sleep that works the magic of overcoming stress.
Serious athletes do workouts in order to improve their performance. Some of that improvement comes from perfecting technique, but for endurance athletes there is no substitute for long, tiresome workouts that stress the cardiovascular system as well as the muscles that provide propulsion.
To maximize improvement we must tiptoe along the bounder of too much stress. Regardless of how much experience we have, there will be times when we cross that border. The older we get the narrower the gap. Without adjustment our subsequent training will suffer. We could end up going deeper and deeper into that black forest of fatigue.
How do we know when have been working too hard? There is no easy answer. I have started using a new process, but before I get into that I want to share what Friel has to say about Morning Warnings.
Friel suggests getting into the habit of monitoring a set of stress indicator metrics and learning to use them to decide when you need to back off. I think of it as a chef tasting the food as it is being prepared. Just as no chef can expect to blindly follow a recipe and have a dish turn out well, neither should an athlete expect success just by following a training plan.
What can the athlete "taste?" One place to start is the TrainingPeaks Performance Management Chart (PMC). With a little practice an athlete can read the ups and downs of the three computed values and get a sense of how they are doing. This is useful, but since the values are based on a mathematical model we should treat the results only as an approximation.
A different approach is to track a set of metrics. Some are objective and some are subjective, but as long as the athlete is honest in their self-assessment the results are quite useful. Here is a list of metrics suggested by Friel, to be assessed first thing in the morning:
| INDICATOR | WARNING |
|---|---|
| Sleep | Poor quality and/or inadequate length |
| Overall feeling | Very fatigued, very stressed |
| Mood | Unusually grumpy, out of sorts |
| Appetite | Diminished |
| Motivation to train | Low |
| Muscles, joints | Sore |
| Waking pulse | High |
| Comparison of supine and standing heart rates | Differential increased |
| Heart rate variability | Low |
(from Friel, pg 175.)
All of these are available as metrics in TrainingPeaks and can be entered daily using the website calendar or the smartphone app. In fact, I count sixty metrics available! You choose which ones you want to track and only those will be displayed.
It is that last one that am focused on here. Which is not to imply that they others are less useful. I just happen to find tracking Heart Rate Variability (HRV) especially enlightening.
What is HRV? To put it simply, when we measure heart rate we describe it in units of beats per minute (BPM). 60 BPM would be a good resting heart rate, 100 BPM is starting to work with some effort, and 200 BPM is going extremely hard.
It turns out that the heart does not beat at a steady rate. The time between pulses varies. This is especially noticeable at low heart rates. Research shows that the more fatigued we are, the less variation between beats. Yes, that sounds backwards, but that is how it is. A high HRV indicates we are rested. A low HRV means we are fatigued. High and low HRV is not the same as high and low heart rate. Again, the best time to test for HRV is when we are sitting still with a heart rate close to our resting heart rate. To be useful we need to track HRV every day at the same time and conditions. As soon as possible after waking up is best.
How to measure HRV? My Garmin FR935 has an HRV test, but in spite of having a built-in heart rate monitor the HRV test requires a chest strap, for better accuracy. I don't relish having to put on a chest strap as soon as I wake up. Besides, all the Garmin app does is give you a number. You have to log it and interpret it yourself.
After a bit of Googling I came up with a better solution. An app called HRV4 Training. It uses the camera in my Android phone to read my heart rate and compute HRV. No chest strap required, although it does support Bluetooth straps if that is what you prefer. I think camera quality may be a factor. When you set up the app it tests your phone's camera, and mine worked fine.
The app needs to collect a few days of data before it can start offering advice. It was very clear about this, no guesswork. After that, at the end of the test it displays the results as above or below your personal baseline. After taking a reading the app has you answer a bunch of metrics questions, just like Friel's suggestions.
But wait, it gets even better. You can sync the app to your TrainingPeaks account. You don't have to for it to be useful, but if you use TrainingPeaks you will want to do this. While evaluating your reading the app looks at the training you did the day before and includes it in your assessment. Then, after you complete the questionnaire, it uploads the results to TrainingPeaks as a metrics entry in your calendar. How cool is that?
I have been using the app for about a month and find its results spot on. Most days it says I am fine and to train as planned. Twice it told me to back off, and once it indicated I was well rested and should really go for it.
I have not tried to do an exhaustive review of every HRV app out there. I just happened to find this one and find it to be really useful. If you find something else useful, please drop me a line.
