Updated: Dec 19, 2018
Measuring morning resting heart rate is one of the easiest ways to measure fatigue of nervous system. Every so often, I use this as a measurement of whether or not my body needs a rest day.
On average, most people tend to have set rest days during the week, but what if you are taking a rest day when your body is actually perfectly fine to be working out. On the flip side, maybe it’s the end of the week and you are just “grinding” through your programming to try and make it out alive.
While muscle fatigue/soreness is also a great indicator of whether or not a rest day may be beneficial, heart rate is a fantastic way to measure this as well. This morning I woke up and felt a little “off” (I can usually tell when my resting HR is a little higher than usual from experience). I took my resting heart rate and it was 59 BPM, about 7-9 more BPM than usual. I always take it in the morning prior to drinking caffeine or exercising in order to have an accurate reading.
Based off this, my training will change. Because I can’t workout tomorrow, I will still train today but it will be at a lower intensity than usual. I will not be doing any WODs to jack up my heart rate or moving big loads for multiple reps.
Takeaway: A good indicator of this is when your heart rate is 7+ BPM than your normal resting HR. A couple beats off is usually not a sign of nervous system fatigue.