We all have good days and bad days, and it applies to the gym as well. When you’re weighing your bar close to your personal deadlift record, there’s no way to know if you’re going to have one of those good days. Sometimes, even warm-ups are painful, and every minute at the gym feels eternal. The reason is not always nutrition but the current state of your nervous system.
You will have more successful workout sessions if you have an understanding of how prepared your nervous system is to keep up the pace. There are tools to do that, and even though your nervous system is an internal aspect of your health that is difficult to evaluate, your heart rate holds much information to assess the function of the autonomic nervous system through a measurement called heart rate variability.
What is heart rate variability?
Your heart rate depends on your level of activity, but it typically goes up and down, even if you’re not actually making intervals between resting and exercising. If you connect yourself to a heart rate monitor at rest, you will see the reading going up and down on the go, even if you’re not changing your position. This variability in your heart rate is normal and depends on respiration and the sympathetic and parasympathetic tone of your autonomic nervous system.
Your heart rate variability varies throughout the day, depending on the predominance of your sympathetic or parasympathetic nervous system. In a general sense, we can say that the sympathetic nervous system (during intense exercise or stress) reduces your heart rate variability while the parasympathetic nervous system (during resting and recovery periods) increases this measurement.
Applying heart rate variability to your training
Studies show that physically active individuals and elite athletes with high performance have a low heart rate variability during periods of intense exercise and elevated heart rate variability readings during resting and recovery periods. This reflects an acute activation of the sympathetic nervous system when they are working out and a shift to favor the parasympathetic nervous system during resting periods to promote a faster recovery.
This does not happen when you’re overtraining your body, and in these cases, you will be able to see high readings of heart rate variability for a prolonged time (even during exercise) because your sympathetic nervous system is chronically activated and your sympathetic nervous system is becoming impaired (adrenal fatigue).
Implementing heart rate variability in your training is not difficult, but since every individual is different, the first step to take is figuring out your baseline HRV. To do that, reduce the intensity of your workout program for one week and then start measuring your HRV every morning and during workouts and resting phases. Log your workouts, sleep, any disease you may have, your nutrition, and anything that may contribute to nervous stress or recovery.
After figuring out your baseline, you will be able to see heart rate variability during workout and recovery periods and correlate data with the intensity of your training, your sleep, and your recovery time. Keep in mind that elevated readings of heart rate variability during exercise might imply a depression in your parasympathetic nervous system, and it is a sign of overtraining. That is how you can keep track of the quality of recovery and program your workouts according to the stress upon your nervous system by using an uncomplicated measure such as heart rate variability.