Using Heart Rate to Measure Fatigue, Monitor Recovery and Know When to Train Hard Again
While I’ve written before about why I prefer not to train and coach by heart rate, I have found that for assessing recovery and how the body is adapting to training it can be a great tool.
Specifically, runners can measure their resting heart rate over time to:
1. Assess their gains in fitness during long bouts of training without tune-up races.
2. Use this data to track when they might be overtraining or not properly recovered from their last hard workout.
Luckily, this neat little trick doesn’t even require the use of a heart rate monitor. You just need to be able to take your pulse and record the numbers. In this article, I am going to teach you the specifics of why this works and show you how you can help identify one of the major signs of overtraining in just one minute a day.
How to use your morning heart rate to measure fitness and fatigue
Measuring your morning heart rate is pretty simple.
- Keep a digital watch (if you don’t wear one to bed), a small notebook or piece of paper, and a pen on your nightstand.
- As soon as you wake up in the morning, find your pulse either on your neck, just under your chin, or on your wrist.
- Count the number of times your heart beats for 20 seconds (time it with your watch).
- Multiply this number by 3 and you have your resting heart rate in beats per minute (bpm).
- Record this number in your notebook next to the day’s date.
You’ll now have an accurate record of your morning heart rate that you can reference after difficult workouts to ensure you’re recovered or when you think you might be facing a case of overtraining. Make sure you get at least three weeks of data before trying to glean any insight from these numbers.
How to use this data
For the two or three days after a hard workout, monitor your heart rate each morning. If it’s significantly elevated (seven or more beats per minute) from it’s normal average, you’re not fully recovered.
Remember, there is going to be some variability in your heart rate regardless of your recovery level. So, don’t be concerned if you’re 3-4 bpm over your normal.
In my experience, it needs to be at least 7 bpm more than normal to signify training fatigue.
You can also use this data to identify long-term trends. If you notice your heart rate steadily increasing over a two- or three-week period, it’s quite possible you’re overtraining or not scheduling enough recovery time.
Consider taking a scheduled down week and monitor how your body and heart rate respond.
Conversely, if you see your heart rate is slowly declining, it’s probably a good indication you’re getting fitter. If you haven’t raced in a while, this can be a great boost to your motivation.
While the scientific research has not been conclusive, the preliminary results demonstrate that an increasing heart rate is linked with training fatigue.
Take a few extra recovery days — a light week of training never hurt anyone. Have the courage to listen to your body and rest!
Why morning heart rate data works
From a physiological perspective, measuring heart rate data to measure fatigue works because heart rate modulation is determined by the effect of the muscular contractions and nervous signals of both branches of the autonomic nervous system on the myocardium and the sinus node.
Increased parasympathetic nervous activity slows heart rate, whereas increased sympathetic nervous activity accelerates heart rate.
The autonomic nervous system also fulfills a pivotal role in stress tolerance.
Consequently, negative adaptation to training stress potentially involves the autonomic nervous system, and may result in an altered heart rate.
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My normal aversion to heart rate training is that I’ve found the data to be unreliable.
When training, you need to factor in weather, stress, stimulant (like caffeine) intake, stress, and of course the variability of the monitor itself.
However, measuring heart rate at the same time each morning avoids many of these potential pitfalls.
While there is still the potential for some variability (like a bad night’s sleep or daily heart rate variations of 2-3bpm), it is far less compared to when used in training. Therefore, morning heart rate can provide more reliable data.
Using morning heart rate data, if taken regularly, can be an easy, effective method for monitoring fatigue, adaptation to workouts, and preventing long-term overtraining.
Considering it takes less than a minute to perform, it’s an essential tool you should be adding to your daily routine to ensure you’re training optimally.