Get access to everything we publish when you sign up for Outside+.
Even though I prefer not to train and coach by heart rate, I have found that using these numbers can be a great tool when it comes to assessing recovery and how the body is adapting to training. Specifically, runners can measure their resting heart rate over time to assess their gains in fitness during long bouts of training without tune-up races and also to track when they might be overtraining or not properly recovered from their last hard workout.
This neat little trick doesn’t even require the use of a heart rate monitor. All you need is to be able to take your pulse and record the numbers. Over the following pages, I’ll explain why this strategy works and show you how to identify one of the major signs of overtraining in just one minute a day.
Using Morning Heart Rate To Measure Fitness & Fatigue
Measuring your morning heart rate is pretty simple. All you need is a digital watch, a small notebook and a pen on your nightstand. As soon as you wake up in the morning, find your pulse on your neck, just under your chin, or on your wrist. Using the watch, count the number of times your heart beats for 20 seconds. Multiply this number by three and you have your resting heart rate (RHR) in beats per minute (bpm). Record this number in your notebook next to the day’s date. Now make sure to repeat this process every morning.
With each passing day, you’re creating an accurate record of your morning heart rate that you can reference after challenging workouts to ensure that you’re recovered. You can also look at this data when you think you might be facing a case of overtraining. Before trying to glean any insight from these numbers, however, be sure to record at least three weeks of data.
How to use this data:
Keep an eye on your resting morning heart rate in the two or three days after a hard workout. If it’s significantly elevated from its normal average (7 or more beats per minute), that’s a sign that you’re not fully recovered from the workout. Remember, there is going to be some variability in your daily heart rate regardless of your recovery level, don’t be concerned if you’re 3 to 4 bpm over your normal average on a given day. In my experience, it takes a reading that’s 7 bpm higher than normal to signify excessive 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 between workouts. In this circumstance, consider taking a down week and monitor how your body and heart rate respond to the extra recovery.
On the opposite spectrum, if you see your heart rate is slowly declining, it’s usually a good indication that you’re getting fitter! If you haven’t raced in a while, this can be a great boost to your motivation.
While scientific research has not conclusively proven that long-term resting heart rate equates specifically to overtraining, there is data that seems to indicate there is a high probability that an increased heart rate is associated with training fatigue. Taking a few extra recovery days after a tough workout or a light week of training never hurt anyone. You need to have the courage to rest!
Why Morning Heart Rate Data Works
From a physiological perspective, measuring heart rate data to determine 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 the 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.
My aversion to training strictly by heart rate is that I’ve often found the data to be unreliable. When training, you need to factor in weather, stress, stimulant intake (e.g. caffeine consumption), 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 variation of 2-4 bpm), it is far less so compared to when used every day in training. In short, tracking morning heart rate can provide more reliable data.
Morning heart rate data, if tracked regularly, can be an easy, effective method for monitoring fatigue levels, how well you’re adapting to workouts, and can help prevent long-term overtraining. Considering it takes less than a minute to perform, there’s no excuse for not adding this simple practice to your daily routine to ensure you’re training optimally and recovering well between workouts.