I know one thing having just worked out today sweatin like a hog, getting old sucks quite a bit. It's like my head is pounding, veins showin, tireder eyes, just delirious. I'm trying to rid my love handles, everythang else is tone, quick, and balanced/accurate. I'm doing some core exercises on my belly raising opposite arms/legs but it's a slow process. So Hiit for 30 mins with various exercises in between ending with burpees (which now I am pretty damn good at now that I'm fit but it leaves you sucking wind at the end), then I'll go another 30-minute round after that after a 2-3 minute rest. If I have the wrong music playing it makes it tougher, I feel weaker and but I gotta push through and not stop and change the music. I create playlists every week from spotify - have been for years so I probably have 70+ playlists but usually only listen to the current "newer" one which sometimes have music that I haven't really clearly vetted as being "cool" and it kinda drains me in a workout. If I were to construct a specific playlist to workout it may aid me better. I've done it will no music and it worked out fine too, but now I prefer music even though the workout is changed up all the time never doing the same thing Every time.
Mainly my shoulders start hurting first, I guess burning would be the word so they take the brunt and my gut sometimes gets less burn cause the shoulders/arms are doin the work on particular exercises to attack the gut. It's just those love handles that are hard to eliminate, very unsightly in a photo or at the beach. Everything else is tone, muscular and fit. I know some boxers/fighters have love handles, but really they shouldn't if they're any serious. Some make due.