Just over a year ago, I began bicycling. Partially due to the situation at the time and also because I just enjoyed it, I became more or less "addicted" in a way. I first rode probably 3 times per week, for 30 minutes. Over the course of a couple of months, this increased to nearly 7 days per week for varying durations between 30 minutes to 1 hour. Probably 4 months into my bike journey, I was riding on avg. 5 days per week for 1 hour and 20 minutes to over 2 hours per ride. I started to really enjoy the longer rides. These rides were mostly not casual either, many days, I would essentially be "racing" myself or "racing" cars, etc... Going at probably 70-90% of full capacity for most of the rides. I found the thrill of the speed fun and distracting from how hard I was working out.
During all of this, I had also still continued to lift weights 0-3 days per week, but the focus was certainly on bicycling. However, as a weight lifter of 15 years, I did what I had to to not just eat through all of my muscle tissue, this worked.
Finally, about 7 months ago (so 6-7 months into my bicycling), I decided to start alternating workout weeks. One week, I would cycle all week, and the next, I would lift. I would do one lifting day during my cycling week, and one cycling day during my lifting week. This seemed to work surprisingly well because I did not put on any extra fat, while I was still able to actually build muscle.
During my "prime" that I described above, I was hitting weeks with 800+ "intensity minutes" as measured by Garmin. Back when I had a FitBit for a brief period, results were similar but I remember the FitBit even saying more because I think the rules for the active minutes are more forgiving. Lately, I've "toned it down a bit", and I tend to have more 600 intensity minute weeks, and occasionally 400.
However, I'm noticing that it's become more and more difficult for me to go to sleep, simply because I am rarely tired. So, it almost seems like doing so much exercise increased my body's capacity and expectation of energy expenditure throughout the day. So now, if I literally don't go and do a 1.5-2 hour weight training session, followed by a 1-2 hour bike ride, I'm not even tired at the end of the day. This in turn, leads to me sleeping less, not because I'm being woken up by anything in particular, but just because my body decides to wake up and doesn't seem to need the sleep. Whenever I've been really exhausted, I would have no issue getting to sleep and sleeping in, however, these days if I don't work out for like 4 hours, I get to bed late and wake up early.
I'm not joking when I say that I've had days where I slept nearly not at all (~2 hrs), then woke up and went to the gym and not only had a full workout, but actually broke personal records on lifts like squat, deadlift, etc... Eventually, I'll get tired but it can take a couple of days of this in a row unless I exercise for like 4 vigorous hours. Note that I also eat very "clean" - I essentially only eat grilled/unfried meats, green vegetables, beans, rice and things like this.
Is this an anomaly or is this something that is relatively well known or studied in the fitness community? Is there any more elegant way to stabilize my energy levels for "off-season" or times I am trying to cut back? This has me concerned as I know sleep quantity is important, but it also doesn't make sense to "force" it... It doesn't work.