How much rest should a bodybuilder take between sets? It all depends on your training goals.  If you are looking to get stronger: the best rest periods is 3 to 5 minutes between sets. The Discovery Channel once did a documentary on the 2000 Olympic Gold Medal Olympic weightlifter Winner Naim Suleymanoglu from Bulgaria otherwise known as “Pocket Hercules.”  He became the second lifter (of only seven) to clean and jerk three times his bodyweight in history. Amazingly, he smokes about 50 cigarettes a day and sometimes between sets he would catch a quick smoke during those 5 minute rest periods! This is unheard of in the bodybuilding world! If you are a bodybuilder, to increase muscle mass training consists of the rest periods of 1 or so between sets.  Often when competition dates approach and bodybuilders want to get leaner; you will see bodybuilders taking even less rest periods between sets.  Bodybuilders somehow mysteriously knew that increasing exercise intensity by reducing rest periods did something to increase fat metabolism there was no research as to how this was being accomplished. It’s as if this was mysteriously passed down from generation to generation of bodybuilders without the science to back it up.  Frank Zane 3X Mr. Olympia had unbelievable definition for a bodybuilder in the 70’s.  When asked how he achieved his definition he said,  

“That comes from experience. When you really get into your workout, the last month before a contest, the concentration is so keen (no talking, and almost no rest) going through maximum effort each set. It's sort of like everything disappears except what you are into at the time.”

Higher Intensity Exercise Results in Greater Fat Loss

Bodybuilders have always known that increasing exercise intensity increases fat burning but the mechanism was not really clear.  Perhaps the most compelling evidence on the effects of high-intensity exercise came in 1994 in the journal Metabolism.  This study tracked two groups of people undergoing different modes of exercise. Group 1 did zone aerobic training for a period of 20 weeks, while Group 2 did 15 weeks of a high-intensity interval program. The researchers wanted to see how each program would affect body fatness and metabolism. The results showed that the aerobic group burned 48% more calories than the interval group over the course of the study. However, despite the huge caloric disadvantage, the interval group had a ninefold greater loss in subcutaneous fat. Additionally, resting levels of 3-hydroxyacyl coenzyme A dehydrogenase (HADH), an enzymatic marker of fat-burning, were significantly elevated in the interval group¹¹. Many bodybuilders often perform aerobic exercise before a show but would performing interval training be better for fat loss?  It has been shown that there is a rise in lipolysis during the⁵. post-exercise periodSomething is going on in the post-exercise period that was causing the high intensity group to burn more fat.  The trigger for this increase in post exercise metabolism fat loss seems to point toward GH.

GH Increases are Dependent on Training Intensity

The most powerful, non pharmacological stimuli for GH secretion are sleep and exercise.  Exercise is a powerful stimulator of GH secretion, and the size of the increase in exercise GH is related to the exercise intensity¹. A single 30-s treadmill sprint to exercise failure produces a near-maximal GH response with GH levels remaining elevated for at least 60 min postexercise².   As serum GH was still approximately ten times higher than baseline after 1 h of recovery after maximal sprint exercises, it is suggested that the exercise-induced increase in GH could have important physiological effects in building mass, including increased protein synthesis and sparing of protein breakdown leading to increased muscle mass. Although this study looked at sprints to maximal failure, studies which have utilized squats and deadlifts to failure have elicited similar GH responses, the point I am trying to get across is that as training intensity increases..so does GH! In a recent study published in the European Journal of Applied Physiology, Bill Kraemer a world renowned exercise endocrinologist wrote, “The importance of greater GH response to exercise cannot be understated in terms of muscle signaling pathways.  GH plays an important role in protein synthesis via interactions with the GH receptor on the cell membrane and subsequently increases in translation efficiency.”²⁰ The anabolic actions of GH cannot be emphasized enough for increase protein synthesis.