My wife and I used to sleep in on the weekends: 10:00, 11:00, sometimes even until noon. Even knowing that I usually feel like garbage when I sleep in too late, the only time we would get up early was for special events or the morning liturgy. A friend and seasoned parent made a comment to me in Church one Sunday whilst my wife was still pregnant. He advised me to enjoy sleeping peacefully through the night because it will likely be the last after my daughter was born. He wasn't referring to the broken periods of rest when your newborn wakes up hungry (or whatever reason). He went on to explain that after your child is born, it's like something changes in your own body chemistry and that you begin to sleep lighter, almost like slumbering with one eye open. I guffawed him at that, figuring he was just another veteran Dad trying to tease me and get a rise.
I sigh now wishing that was all it was. As it stands now, full peaceful nights of rest are uncommon. It's like an instinct to protect has engaged and I find myself at best lightly slumbering - always with my ear alert and aware for the sounds of my daughter. In the beginning disruptions to my sleep were magnified by the infant monitor we were using as I could then hear every sneeze, cough, yelp, moan and cry of my daughter. Most of the time it was her just yelling or laughing or something weird in her sleep. Nonetheless, it would be enough to cause me to stir. I was ever so happy to finally turn off the monitor at night(she is 18 months now) so I'm no longer awoken by her every toss and turn. Our room is close enough to her room that I can hear at night if she cries. Another funny thing that changed is my inability to sleep in. I never used to be a slave to the morning routine, I woke up when I wanted or needed to.
Again, it is like something changes as I know find myself up bright and early in the morning, regardless of whether it is a weekday or weekend. Even if my daughter affords me the luxury of sleeping in on the weekend (by doing so herself), I still lie awake in bed with the new day. I have no idea what happened, maybe I'm just getting old.