Let's come back to the aspect of sleep fragmentation. One of the problematic issues, and the underlying causes of this sleep fragmentation, is that with alcohol. In your system, it will activate and stimulate what we call the fight or flight branch of your nervous system. The Term for which is your sympathetic nervous system. I've always wondered about this by there. It is very poorly named your sympathetic nervous system is anything but sympathetic, it's very agitating and very activating now. Normally we have to shut down the fight-or-flight branch of the sympathetic nervous system in order to fall asleep naturally and then stay asleep soundly across the night. So in other words, we have to shift away from that fight or flight branch of the nervous system as we're getting ready for bed. And as were falling asleep and move over into the more passive. The more quiet hasn't or what we call the parasympathetic nervous system yet. Alcohol will force you back over into the fight-or-flight state of the nervous system. And this is one of the reasons why your sleep becomes so much more fragile and so much more likely to be littered. With these fragmented Awakenings throughout the night. The second underlying cause of that sleep fragmentation is that alcohol will also trigger the release of a number of stress-related chemicals within the brain and the body including one specific hormone called cortisol. And normally cortisol has to go down as we're falling asleep and it hits its lowest point. Throughout the middle of the night. Yet alcohol can Spike those levels of Saul activating the nervous system and the brain and therefore making it more likely that we wake up.
Alcohol Activates the Sympathetic Nervous System, Increasing Sleep Fragmentation