When we write articles, we try to choose topics that the LBEB community has asked about. One of the most frequent questions by new and old members alike is "How much rest do I need between sets?" This question is often accompanied with "I heard that if your workout is longer than 45 minutes, your testosterone starts lowering itself." This mantra is repeated almost as often as the Squats & Knees debate. Let's take a deeper look into these claims to see if they possess actual merit, or it is just bro-science rearing it's ugly head.
1. Rest Intervals Between Sets
Whether we like it or not, most of us probably started lifting by doing the traditional body-split routine in the gym (back and bi's, chest and tri's, ect.) and heard the advice floating around the gym that you needed to keep your rest intervals between sets at 90 seconds or less. This claim has the potential to be somewhat true for those solely in search of hypertrophic gains, but certainly not true for those in search of both absolute strength and muscle gains.
According to several sets of research, as well as my personal coaching observations, the optimal rest period for the majority of strength athletes (excluding those involved in HIIT) seems to be 3-5 minutes during sets of working weight. I personally take 1-2 minutes during warm up sets of squats or deadlifts up to about 65% of my max, then begin the 3-5 minute rest period. While a 1-2 minute rest period during attempts at 90+% of maximum is feasible, from a physiological and psychological standpoint, it is hardly ideal.
When someone asks me how long they should rest, I simply tell them "As long as it takes for you to finish the next set correctly." That is really what it all boils down to: You aren't in a race when you are hitting your heavy sets of squats, deadlifts, or snatches, so don't train like it. Patience can be a virtue in the gym, and it is ridiculous to me that some people blow the load on their workouts because they can't rest for more than 30 seconds without going on to the next set. I understand that some may have a time constraint due to other duties in life, but adjusting your workouts would be smarter than shortening the rest period between heavy sets. If you find yourself becoming agitated or anxious for your next set, get away from the weight you are working with, and listen to a 3-5 minute song EVERY TIME to force yourself to wait. In my opinion,it is better to hit a lift with a clear head than to hit with an agitate, false sense of confidence.
2. Workout Length and Testosterone Levels
Another "fact" that is tossed around the fitness community is the claim that workouts need to be kept under 45 minutes: Any workouts over 45 minutes will contribute to drastically low testosterone levels. If this were true, nearly every top-level strength athlete on the planet would be absolutely screwed. Our training sessions regularly run 90-120 minutes, when rest and warm up are factored in. Not only is this claim ridiculous on its own, it is even worse if someone factors their 3-5 minute rest periods into it. I have met men and women who will cut their own workouts short when the 45 minute marker is reached, essentially focusing only on the movements they like, and neglecting those they actually need to work on.
This claim comes from Soviet era research, which stated that 45+ minutes of cardio exercise could result in increased cortisol levels. This does not mean that testosterone would be lowered, and it certainly doesn't pertain to a strength training session, where movements are being hit for 10-45 seconds, followed by a rest period of 3-5 minutes. Some would say that if you can't get your workout finished within 45 minutes, you need to change your programming. I say that if you can race through your workout, you probably aren't lifting very big and you might want to put down the 8lb dumbbells and start moving serious weight.
As I have said before, there is what science says works, and there is what actually works, so find out what rest intervals work for you, and plan accordingly. If you find yourself consistently missing reps on your 2nd, 3rd, 4th, 5th sets, you might want to try adding in more rest to your workouts so you can hit each set with renewed vigor.