Definitely not a bad habit. Sigh.

If you for example would measure your body temp throughout the day it varies, but in someone with DSPS it varies with the internal rhythm while normal people's temp vary so when they fall asleep the catch onto a sinking body temp and when they wake up, it starts to rise.

In DSPS the pattern can be chaotic or the body temp starts sinking early in the morning and keep sinking to noon or longer.

Also the hormone which is meant to concentrate urine should be higher at night so you don't have to go up and pee, but people with DSPS might have to (if they can sleep nights) because this doesn't kick in until early daytime. Me personally I almost don't pee in the day, only at night.

So yea... a real physical thing.

I wish people would understand but I can't help if people choose to be stupid.