Been bodybuilding-type training for 31 years (straight).
It has been suggested to me to attempt HIIT cardio while on TRT. I tried this 3 weeks in a row and literally drove myself into a huge hole as far as recovery goes. Just felt awful.
Wondered if anyone here might have some suggestions for some general cardio (for heart health)?
TIA!
I’ll assume you are around age 50 based on this.
At your age and with 31 years of lifting mileage I can’t imagine this being a great idea. I would suggest you find something low impact that still elevates heart rate. Such things consist of rowing, swimming, elliptical etc.
Yes, bang on. Will be turning 50 yrs. old in a couple months.
Thanks very much for the advice. 
I tend to agree w/ you. I don’t mind biking or treadmill work (inside or outside), so hopefully that will work.
I really didn’t realize how much that HIIT work would drive me down.
I should be careful and clarify that I’m not dogging on any style training. If you really like that style, you could alternate with the less impact type training and ease yourself into it. Sounds like you went pretty hard pretty fast. I dunno… assumptions again 
Understood and thank you.
BTW…your assumptions are correct. Need to learn how to ramp up gradually I suppose.
HIIT can be low impact i.e interval swimming
Exercise selection is important. Doing parkour and sprint intervals followed by flips on a gymnast trampoline is higher in impact relative to intervals on a rowing machine or swimming sprints in a pool
What OP can do is deternined by which body parts (if any) are giving out, how much arthritis OP has (arthritis pain can be a bitch), any labral tears or RC pathology (degenerative tears common with age, tend to be less symptomatic than traumatic tears but can be bothersome)
Op has been lifting for decades and thus likely has a base level of fitness. Running, jumping and acrobatic manouvres put a lot of stress on the body. Exercises that don’t expose joints to repeated bouts of loading over long durations of time are preferable.
Cycling better than running
Swimming (if shoulders tolerate) is good.
Thanks guys. Appreciate all the advice for sure.
Did some steady state work on Schwinn Airdyne bike tonight. Can’t begin to tell you how much better this went!!
Hiit should be used in moderation as it creates a lot of fatigue. Try 80% time steady state and 20% hiit. For me that equates ti about 2 hours a week hiit and 8 hours steady state… but im a cyclists.
For you this might be 20 mins hard hiit and 80 mins steady state cardio a week.
I value my perceived confidence that I’ll stick to things I add to a training plan. I have tried doing HIIT stuff. Never lasted much more than two weeks. Just wore me out too much. Took away from my lifting.
I’ve been walking on a treadmill at an incline every gym session for about 8 months now. It has improved my conditioning, and improved things like BP and heart rate. I feel I can stick to this long term.
It doesn’t sound like much, but how many people out there are walking up a hill for 30 minutes a time 4 times a week? I don’t recommend starting too hard with anything you choose. Build the habit of always doing it when you are supposed to. Then gradually increase how hard it is. I started with 20 minutes, and less incline. It fits my goals. I intend to look like I lift more so than I do endurance running. I want to be conditioned and good overall shape, but it isn’t my main goal.
Another thing that has improved my conditioning is using a workout timer. I usually have a long rest times for things like squats, deadlifts, presses, weighted chins, but once I am doing machines, curls, triceps on the cable machine, I cut the rest periods down. Keeps the heart rate up at bit. I do program in rest times for the squats, deadlifts… I just program in like 4:30 for rest. Doing that made me realize that before the timer I was resting like 7-10 minutes when the sets were tough haha.
I recommend swimming for the best cardio workout, and if you live near the ocean, there’s nothing more enjoyable than swimming up the coast.
I can’t second swimming enough and agree with @systemlord @unreal24278 @blshaw. It is great cardio and conditioning. There are many ways to do it too depending on what you worked out that day. You can do primarily kick on arm days or primarily arm stroke on leg days.