[sedeki]

Same here. But I always associated it with stress.

[xeromal]

I feel the same way but after wearing a heart rate monitor, it definitely detects a higher daily average heart rate so it can't be healthy.

Normal days: 50-55bpm

Low sleep days: 63-68bpm

[NathanielK]

I've noticed similar. I've woken up early, taken my pulse and notice it was a bit high and used that to decide to go back to sleep.