Sometimes it surprises me how many people are in bed at 5 or 6 am. What? That is plain un-American. At least, get up and milk the chickens and feed the cows.
My gym has been meddling with their early morning workout classes (calisthenics and HIIT mostly), partly because of staff turnover and partly just for variety. Maybe Russia was involved in the meddling, cuz we do have a Russian gal trainer there. Probably a spy...
Finally found a good one, a new one, for me this morning. Fast-paced, challenging, exhausting, heavy sweat and heavy breathing but without much shoulder stress. Yes, some burpees which I do not do. I do pushups instead. Modify whenever needed. I am often the oldest person but I don't care because I am in half-decent fitness for my age. At first, I could not keep up. Now I can. A body is a miracle of adaptation.
I recommend finding one or two of those that work for you, as a good complement to weight work and boring "cardio". The classes can look intimidating, but you go at your own pace and do what you can. Improvement ensues, fairly quickly.
Have any of y'all tried them? They can become addictive.