A common myth that has been reported by websites, fitness trainers, and strength coaches is the concept of a specific time frame in which to complete a training session. As the myth goes, all training sessions should be completed within 45-minutes, as after this point the body has a drastic reduction in testosterone. The myth has taken on various forms over the years and sometimes extends up to 60-minutes; with some authors also claiming that the body actually stops producing testosterone. However, the general theory persists that after a certain point the training session is no longer beneficial because of a decrease in testosterone. There is usually a statement following the time recommendation that suggests that this is based on extensive research performed on the Bulgarian national weightlifting team or a similar Eastern European weightlifting powerhouse. The reality of this myth is that there is NO published research to suggest that a decrease in testosterone occurs at 45-minutes, or that a short-term decrease in testosterone would have any effect on immediate performance or long-term training adaptations.
The short-term response of testosterone to strength training is well researched, with the vast majority of reports indicating an increase in testosterone during and in the immediate time following training in healthy adults (Kraemer and Ratamess, 2005). The studies typically do not report the length of the training session, but they have been performed to examine the influence of exercise selection and sequence, training volume and intensity, and rest between sets. Common sense would suggest the training time easily exceeded 45-minutes in many cases, as some of these studies contained 8-10 exercises, with 2-3 sets per exercise. As with most “exercise science” many of these studies were performed with poorly trained college-students. Studies like these always raise doubts of the applicability to athletes or serious strength-trained individuals, but studies have also been done on these folks too, and, unlike the reported Bulgarian studies, these results are easily found and have been widely published and reported (Fry et al., 1994, 2000). The results are the same, testosterone increases following a single workout, and in fact, the better trained the individual the greater the response.
Most trainers and coaches also do not realize that consuming a post-workout (PWO) shake with protein and carbohydrate may actually lead to a decreased testosterone response due to an increase in insulin (Kreider at al., 2007). No one cautions their clients or athletes to avoid proper PWO nutrition, despite the blunted testosterone response, and progress is still made consistently with the lower testosterone. Why? The short-term effects of testosterone to a single session of exercise are inconsequential to long-term performance. Long-term changes, or having testosterone elevated over a period of months and years, have been shown to lead to increased strength, power, hypertrophy, and performance. Short-term; those relationships do not exist.
Now, there are some benefits of keeping your workout short. There is some relationship with using short rest periods between sets (less than 60-seconds), leading to increased lactic acid accumulation, which may influence growth hormone. Having a strict time limit eliminates talking and other wasted effort nonessential to improving performance. The sooner you can get in and get out, the sooner you start to recover and experience an increase in strength and power. Both very good things, but, to suggest that testosterone production will magically stop at 45-minutes is just plain