RE: Stages Of Sleep And The Second Wind Phenomenon
You got me here. I am an usual 5-7 hour per night sleeper. I can't sleep more, since I never want to leave the gone day.. go.
I always have my fitness band to check for pulse and I had another fitness band with an advanced ECG chip and could also measure the HRV. Basically it was like a ECG machine but with only one derivative.
It was called Huami Amazfit and it was pretty cheap ~120$. Sadly, because of the metal electrodes it was not water resistant, and I only found out after I got out from the pool :D
What I can say is that lack of sleep had a very bad influence on concentration, heart health (I have even developed ventricular extrasystoles).
After more testing (by me), I have found that I deep sleep only about 30 minutes per night and I move a lot while in REM.
That was unfortunate. Yes, you were right, lack of sleep can cause poor concentration and general people who sleep less have a reduced performance in the workplace.
What fascinated me was how dedicated you were to discover yourself. I'm impressed.