Hi Dr. Sullivan, I have some questions about exercise rehabilitation of CHF patients, as discussed in your 2013 review. In particular, I am wondering about Piepoli and Crisafulli's paper on exercise intolerance. Their paper is a bit confusing because they blur the line between chronic SNS activation (bad) and acute SNS activation (good, perhaps?). Its connection to strength training seems very unclear. The accumulation of metabolites, which initiates the metaboreflex and in turn heightens sympathetic tone, is characteristic of endurance training or HIT, not strength training. Peculiarly, they claim that CHF patients have a smaller ratio of Type I to Type II fibers, which is the opposite of what I would have expected. Some resistance training protocols seemingly reverse that imbalance — less surprisingly, since they involve 15RMs on machines.

My questions are:
(1) what is going on with the purported Type I/II fiber shift?
(2) in CHF patients and similar, does the metaboreflex (and SNS) activate during proper strength training? Is that desirable?

Thanks. Also, I feel obligated to harp on a few instances where you speak of confirming or accepting null hypotheses. Which, as you know, is not possible.