Hey all, need help from lifters on how to approach a new routine, due to advice from my cardiologist to not strain too much on the weights, due to a defect which causes a tiny leak in the valve. This is NOT a request for  medical advice, but rather a request for advice or suggestions on how to lift and make progress without straining the body.

 I told my doctor that I usually gauge whether I want to progress to more reps or heavier weight by seeing when the last rep becomes challenging, and if I get used to the extra 1/2 reps which are a little more challenging after a few workouts, then I will continue doing them, and continuing making progress with more reps or weight. I think this is a very common approach, but he says, "just don't do that last rep." I actually am not sure on how to make progress by never doing any challenging reps. And since it's not the doctor's job to tell me what options I have, that's why I'm here.

 Wondering what other's thoughts or approach would be? Is it possible to gain strength without at least slightly increasing the challenge at a steady rate?