Andrew Huberman· PhD
but then after that your melatonin level might be beginning to fall and it's not only melatonin in your core body temperature and then your heart rate and everything is changing to make you awake but the Sleep debt that you have accumulated is pushing you to be in bed so there is this tension between the Circadian aspect and your sleep depth and unfortunately you cannot have good night of restorative sleep for the second half of the sleep because of the tension