Posted by: PFB
Q. I've read here and there that low reps at a high fraction of one's 1RM tends to boost testosterone while high reps at a low fraction boosts GH (a response to the higher lactate produced by the latter type of exercise). Is this right? I'm changing back and forth between the two types of exercise every 3rd or 4th time (for each set of muscles - back, chest, etc.) as a kind of periodization, and will eventually have enough empirical evidence to make up my own mind about the results, but any pointers you can furnish would be a great help.
A. The factors involved in modulating testosterone and growth hormone levels are complex and far from being completely worked out. For example, while there are a lot of theories as to what increases growth hormone (everything from the buildup of various metabolites, depletion of glycolytic and TCA substrates to lack of oxygen), it hasn't been nailed down as yet. The overview is that working the big muscle groups using heavy weights over a reasonable period of time will increase both GH and testosterone, although there will be some individual variation as well as some effect from maximizing nutrition in and around training. The bottom line however, is to find out what works best for you by doing exactly what you're doing now, experimenting.