"A lot of people have had a lot of predictability and structure in their day before becoming a mom. If you are already a bit of a worrier, or perfectionist, or hard on yourself, people use structure, predictability and being successful as a way to manage that inner 'stuff'. Then baby comes along and BOOM!… out goes predictability, structure, there are no tangible successes."
The most common cause of early rising is going to bed too late.
It seems counterintuitive, doesn’t it? As parents we often want to push bedtime later and later because our child is waking earlier and earlier. What actually happens by moving bedtime back is that then they are overtired when going to bed. When they are overtired, their body produces Cortisol (which is like a shot of espresso to the system) to keep them up. Going to bed with Cortisol in their system will interfere with the quality of their sleep and will more than likely cause them to wake up too early.
A baby has six arousal states - being asleep, drowsy, hypo-aroused, calmly focused and alert, hyperaroused, then flooded. When a baby gets to the point of being hyperaroused or flooded, they are burning a lot of energy. The only way to help them out of this state is to help them down-regulate and this involves PARENTAL CONTACT/SUPPORT. It is not something that can be done by leaving a baby/child alone. They cannot up-regulate themselves or down-regulate themselves. If a parent does not help them down-regulate in their hyperaroused state, they will go up the arousal scale, become flooded, and at this point, the baby burns so much energy that they may fall asleep - NOT BECAUSE THEY SOOTHED THEMSELVES, but because they are passing out from sheer exhaustion. "It is the brain's last mechanism for protecting itself from severe energy depletion." Dr. Stuart Shanker, 2016