I believe it to be somewhat true. Back when I trained hard on morning, nap then exercise again during the evening, I noticed my resting heart rate would be qui

I believe it to be somewhat true. Back when I trained hard on morning, nap then exercise again during the evening, I noticed my resting heart rate would be quite high after the exercise, something like 70 when it’s under 50 normally and stay like that for around 4 to 5 hours. On the other hand, it never prevented me from napping. Quite the opposite, so I’m surprised it has such a dramatic impact on sleep quality. ItIt could be linked to cortisol tho, increase cortisol high enough and even though you’re not fully rested you can’t sleep anymore and feel like shit. So you sleep a little, recover barely enough but too stressed to recover 100%.