How about because I live a healthy life with plenty of exercise along with meditating on a routine basis. My heart rate reads at 58bpm but is working on getting a more efficient rate.

REM rebound is not normal or associated with exercise or meditation. I'm not saying you are unhealthy in a general sense, I am simply saying your sleep deprivation is unhealthy. Whether you feel "fine" or not isn't the point, it is still unhealthy and can have long term consequences. 

Although 58 bpm resting is pretty dang good, that's a runner's BPM to be sure. I remember when my best friend used to run track, he would have a resting BPM of 44! 

Taken off of worldrecordacademy:

Daniel Green achieved the world record for the slowest heartbeat in a healthy human with a heart rate of just 26 bpm

I'm hoping to reach my heartrate at that level, too. Perhaps, I'm not taking what you said into account. I may be pushing myself a little too hard too fast.

Thank you for your input.

Most times I get 7-8 hours but sometimes 6. On holidays and weekends 12 hours.

I operated for years on 6 hours of sleep. A few months ago I got a puppy and that demands set sleep schedule and I've recently improved to 8 hours per night. The difference is astounding. I have absolutely no problems staying focused on extremely boring meetings with this increased sleep. Highly recommend.

I can manage with 7 hours, but 8-9 hours is better for me.

5-6, give or take, provided I'm not disturbed.

8 is good for me. I can go a couple days with 4 to 6 hours but after that I’ll need a 10 sleep to catch up. So 8 seems to be ideal for me.

I assume you are joking, but if you aren't joking... that is dangerous and could indicate a sleep disorder.

7-8 hours every day of the week. If I guess less, it shows immediately.