De-training Due to Potential Cardiac Issues. How can I Keep Heart-rate Down at the Gym?

Hi all,
I have been asked by doctors to detrain for six months to further and better investigate some cardiac signs which could be suggesting of a pathology. I have done all possible exams (holter, ultrasound, MRI), and as of today they are unable to have a clear diagnosis (they initially thought I had myocardiopathy).

There is not much evidence about how detraining should work: one doctor told me I can do everything, as long as I can talk while exercising, but probably should avoid weights. Another doctor almost the opposite, that is, that I should entirely avoid endurance exercise, but can do weights as long as I don’t load too much and exert excessively, trying to stay below 60% of my maximal heart rate (approximately 110).
I’m planning to do maybe 1-2 easy endurance rides a week, and also 1-2 gym weekly sessions.
Per my question: so far I had been lifting main lifts (squat, bench press, etc) with 5x5. I’m wondering if 5x5 is the optimal mix to keep heart rate low, or if instead I should be doing something different (lower load more repetitions? higher load, less repetitions, more series?)

Sorry to hear that, it’s frustrating when you don’t know what’s wrong.

Does your heart rate get above 60% of your max a lot when you lift? There are several things you can do to keep it down: take longer breaks in between sets and reduce the intensity of the lifts (less kgs). The lifts you’re doing are compound exercises, which increase heart rate relatively fast. Consider swapping exercises - a leg press/leg extension instead of squats, a seated DB shoulder press instead of BB overhead presses, while keeping several reps in reserve. For the mind, it might be good to choose some specific areas for improvement that don’t require lifting hard (stabilising muscles that will support your main lifts, flexibility, stability, core, etc).

Thank you, the uncertainty is quite frustrating for sure, and being able to do something, anything, while waiting, certainly helps.
I haven’t kept an eye on the heart-rate while lifting yet, as this is a recent development, but I have a vague memory that it would go around 110-120 while pushing heavy squats, for example.
Based on what you say, looks like more weight will equal more intensity, hence higher bpm. Does this mean I should probably go for lighter weights and, possibly, more reps?

It depends on the exercise. Generally, compound exercises will increase your heart rate faster than isolation exercises. Doing squats at lower intensity (less kgs) but with high reps, your heart rate will surely go up. If you would instead do a leg extension (isolation exercise), you can go to failure but its unlikely to increase your heart rate much.

Another example, when I do BB overhead presses, my heart rate will go up fast. But when I do a seated one arm DB shoulder press I can lift heavy, 1 rep to failure, without seeing too much change in heart rate.

If you want to continue squatting, Id suggest to reduce the weight, do 6 reps, stay several reps away from failure, and take sufficient rest in between sets so that your heart rate goes back to normal after each set. You can easily monitor your heart rate, just give it a try.

Thanks, I’ll give it a try!