Earlier Sleep–Wake Cycle
If you wake up too early in the morning, the reason behind is not always in bad sleeping habits, racing mind, or other external factors. A natural shift in your circadian rhythm can also evoke a tendency of waking up early.
Every one of us has a unique chronotype determining the hour we feel most energetic and perform the best. Some are more early birds than night owls. They are also more prone to waking up early in the morning. However, chronotype can change during your lifetime. Usually, your inner clock shifts towards early morning as you age, and for some, the shift can be quite drastic. In many cases waking up earlier is just a natural part of getting older and not necessarily a problem you should be too worried about.
If waking up "too early" concerns you, here's a little encouragement: It's totally fine to wake up early! If you continuously find yourself waking up at 4 or 5 in the morning feeling somewhat rested, there is no harm in getting out of bed and starting your day a bit early. Don't worry if you didn't sleep long enough. Most likely, you'll get tired earlier the next evening, and eventually, your body will adjust to the earlier rhythm. By listening to your body, you can find the optimal rhythm for you. Not everyone needs to be asleep strictly between 11 pm and 7 am.
Running on an earlier rhythm is perfectly healthy as long as you take care of going to bed early enough to get a sufficient amount of sleep. However, if you are an outgoing person, you might feel that earlier rhythm restricts your social life or evening activities. If that is the case, you can start shifting your rhythm later on purpose.
Example Habits to try
Postpone Your Rhythm
If you have an early sleep-wake rhythm and feel it is restricting your life, you can try shifting...
Fischer, D., Lombardi, D. A., Marucci-Wellman, H., & Roenneberg, T. (2017). Chronotypes in the US – Influence of age and sex. PLoS ONE, 12(6), 1–17.
Gregory, A. (2018). Nodding Off: The Science of Sleep from Cradle to Grave. Bloomsbury Publishing.