I lifted weights, did calisthenics, did 5 rounds of HIIT on stationary bike/rowing(bike before every workout rowing machine only after arm days) then I would finish with 1000 turns of the jump rope. The only thing I noticed was on the third day my strength dropped, in terms of stamina. Typically on set 4 of legs I am slightly fatigued, on the fourth set on third day of fasting I was able to get weight up but I was having to really crank out last reps. Also needed a little more rest between sets. But after I melted a significant amount of body fat
I always plan to avoid exercise during fasting, but then I inadvertently do mammoth stuff, like go for a massive 10k walk or dig up a garden bed, or, recently, chop down a tree. But it’s not purposeful (accidental exercise). And halfway through I think ‘I shouldn’t be doing this! I haven’t eaten for days!’. I do have salt water if I feel a bit lightheaded. And I find the energy and clarity that comes from fasting is amazingly beneficial to get stuff done that I’ve been putting off.
I reduced my intensity by 60% (squatting 60kg instead of 100kg, 50kg bench instead of 80kg etc). During my 72hr fast. I tried to time it so that I break my fast after my 2nd gym session.
It is a work in progress. I’m seeing what works for me. So far so good.