The issue is that internal clock doesn’t always match your expectation of how long you should sleep during the night.
This change can especially be felt during the process of certain life transitions, such as when a person retires and is no longer that active during the day, has less social activities, fewer responsibilities, or quieter evenings than before.
Even then, sleep can still feel refreshing and sound, but starts occurring earlier in the evening. When you become aware of how these transitions affect your sleeping, you can start thinking of ways to align your daily habits with the timing of the body.
3. Physical discomfort and health factors
Waking up in the middle of the night can also be a result of physical discomfort you experience during the day. So when the body rests and there are no other distractions, that minor discomfort you experienced during the day may become significant enough to disrupt your sleep cycle.
Some of the most common contributors include joint or arthritis pain, back pain, acid reflux, dry mouth, cramps, and changes in body temperatures.