Q. Although you're probably best known in the industry for your diet books, you also have a massive amount of knowledge and experience in other areas, particularly strength training. One subject I think readers might be interested in is the hormonal response to exercise. Many people are told to keep the length of their workouts down to 45 minutes or less on the basis that testosterone levels drop and cortisol levels rise after this point. Is this good advice or not?
A. This is going to be another one of those yes and no types of answers.
On the one hand, the idea that testosterone drops after 45 minutes is one of those ideas that falls into the "If you repeat something enough times, it will become accepted dogma."
The idea supposedly came from Bulgarian Olympic lifting coach Ivan Abadjaev who claimed that androgen levels dropped after 30-40 minutes and who pioneered the idea of keeping his athletes in the gym all damn day by having them train for 30 minutes, rest 30 minutes, train again, etc.
As time has passed, it's come out that the main impetus behind his training schedule had more to do with controlling his athletes, simply exhausting them every day to keep them from partying and staying up late.
Just keep them in the gym for 12 hours per day by breaking training up into lots of tiny segments (this probably also allowed them to train intensely at each session) and they go home and sleep when training is over. Bulgaria, under new coaching has moved to a much more traditional system of training with 2-hour workouts as the norm.
As well, what I've seen of American research has never supported the idea of a drop in testosterone, and you can find plenty of successful athletes who spend far more time than that in the gym. Powerlifters, who are often taking very long rests between sets and having to muck with gear are often training 2-3 hours at a stretch.
This isn't to say that the idea of keeping your workouts high quality is a bad one. Certainly, I think that most bodybuilders spend too much unproductive time in the weight room doing too many sets of too many unnecessary exercises. For the natural athlete, quality should predominate over quantity for sure.
But I think setting some arbitrary time limit like 45 or 60 minutes is missing the point. Basically, I think the idea may be useful as sort of a check to keep people from wasting energy and time doing endless sets of useless exercises in the gym, but I don't think it's an absolute. When I train people, I'd say 60-90 minutes is about average. Much more than that and quality falls off too much.
Certainly, shorter workouts tend to be higher quality. By the end of a 2-hour workout, you're unlikely to be putting much effort into things. There is also the issue of crashing blood glucose and a potential increase in cortisol because of it.
That can readily be ameliorated by sipping a carbohydrate or carbohydrate plus protein drink during training. That will keep insulin higher and keep cortisol down during extended training sessions. It may also help to improve intensity.