I was a night owl until about 30, and I enjoyed it too. I didn't plan to become a morning person.

When I had to wake at 4:30 for work, I hated it. Now that I don't have to go to work so early, I love getting up early, because those first couple of hours are my most productive. There are zero distractions and my mind is fresh from a good sleep. I'd rather have these most productive hours for myself, whereas when I was getting up and going straight to work, I'd only have the evening hours where I was already exhausted after working 13 hours.

I'm almost certain I couldn't do it without the proper diet and exercise though. If I let go with the diet or stopped going to the gym, I reckon I'd probably slip back to becoming a night owl, and become more lazy too.

I was a hard-core night owl for years (all through college and my first 20 years of working). Then I had a kid, then another. They're 10 (+/- a bit) and I now reliably wake up sans-alarm at 5-5:30 every day, after years of doing that for [or because of] the kids. They even sleep later than that now, but I'm easily up by then.

It does mean that I'm tired by 11 or midnight, but even when left entirely on my own schedule (kids away on school vacation), my "new" natural schedule persists.

I didn't seek to change it (and if it drifted back later, I might even be slightly happier).

What I've found has helped me to change patterns is to pull an all nighter, then go to sleep at the target time. Its worked for me a few times, until I slowly drift out of sync (I'm definitely not an inherent morning person).

May not work for everyone...

I have kids and I’m still a night owl. Thankfully, I have flexible hours at work so I can work late. When the kids hit school age, we will attempt to find a school that has a later start time.

Anecdotally, at 51 and previously thought the same as you, I'm going to disagree. I'm closing in on two years of getting up at 5:00 am and it doesn't bother me anymore. I never thought it would be possible for me to adapt, but so far I have and I have no intention of changing.

Time will tell.

People's circadian rhythms change over the course of a lifetime very considerably. Trying to keep all age groups on the same schedule is actually a pretty bad idea. Check out the book Why We Sleep. I think especially how we treat adolescents, who are usually late shifted by 2 or 3 hours compared to adults, is going to look barbaric in another 30 years. People think that 9 AM is a "late start" for high school, but it should probably be more like 11 AM. Even the ratios of NREM versus REM sleep change a lot over different age groups.

Additionally, sickness, including common cold, can lengthen sleep enough to make it unreasonable to get to work early, and forcing (mildly) sick people to early work getting them further sick is an accepted practice.

Or running civic services 7 AM - 3 PM which makes it impossible to schedule without a free day or understanding boss. Something that should be available with perhaps only a minor downtime works only for a few hours.

The cumulated morning/evening hours tend to overload transportation facilities too.

I'm with you on all of this. It was an eye-opener visiting other countries (USA native here) that were more laid-back about getting to work and staying at work. Mexico City in particular was nice and relaxed when I worked there for a while.

People tend to wake earlier as they age, maybe that helped?

I've noticed it already in my 30s, I can no longer sleep in so easily and have to get up, even if I'm tired.

Unfortunately it is because older people tend to have poorer sleep quality in general (less time in deep sleep cycles) so that's a pretty big downside.

Possibly but I don't think so in my case. I've worked 9:30 am - 6:30 pm or later for most of my 25 year career. Stayed up until 2 am every night pretty much.

I really did force the change for myself and it totally sucked going through it. I still don't just jump out of bed and feel instantly great. It takes 30 minutes or so to get fully awake. For example, this morning I so did not want to get up because I stayed up until 1 am. However, I did get up at 5:30 am anyway. It was awful and I'm dragging today. Caffeine helps as well.

Maybe there's a hormonal aspect to this? Do you think that's possible, as you're getting to be - please forgive my noting this - past reproductive age [menopause and/or lower testosterone levels come around this age AFAIK].

It's always possible. However, I forced this change. It didn't occur naturally over time.

Huh. Interesting stuff. Well, if mine changes, it changes I guess. I don't object to the idea of a more morning oriented schedule, it's just not who I have been up to this point in my life. And I'm not making any conscious effort to change, as I'm pretty happy with this mode. I like being awake in the wee hours of the morning. One of my favorite things to do is go bike riding (or maybe walking) at 3 or 4 am when nobody else is out and about. Just me, my thoughts, and some music, and the world to myself... or at least that's the way it feels, for an hour or so. :-)

I was really forced into it by wanting to retain my job. If I wasn't working where I am, then I wouldn't have made the change. But I like working where I am just 8 minutes from my house, pretty good job security compared to the tech industry, pretty good benefits, everything else pretty good compared to other jobs in my career. That 8 minute drive is worth so much to me.

I work for a transportation company and there are a lot of field people that have moved in to c-level positions and have the "butts in seats" mentality and I think that's why after 12 years of 9:30 - 10:00 am starts, suddenly I get smacked with a "needs improvement" on my review. And our technology department is having big problems retaining talent.

Same. I used to be a night owl. Now I'm not. I could engineer a switch back if I wanted to, but I like this better, so I don't plan to try.