If you are a follower of 3DMJ then you know where the topic of rest periods falls in the hierarchy of the Muscle and Strength pyramid. It’s 2nd to last in importance and just in case you are not aware, here is a link to the 5th level of the Muscle and Strength Pyramid on YouTube.
During the video, you will notice that never does Eric mention any harmful effects of too much rest. Is there a time where it is harmful? I would say yes, when the rest periods are so long that body temperature falls, your body becomes fully relaxed, and the training mind set is no longer present. Probably would take a while for this to happen, but nonetheless this would be something to avoid.
With this in mind, as long as it’s feasible for the individual to do so, I often recommend (and practice) using rest periods to your advantage in order to hit the numbers prescribed. Keep in mind at the moment I’m training primarily for powerlifting so this really doesn’t apply to bodybuilders, as it’s very load-centric. However, when very aggressive numbers as prescribed by my coach, I do everything in my power to hit those numbers. I train 75–90% of the time in the convenience of my own home. So, that means if I am really tight and I need an extended warm up, I’ll spend the time to do it. If that means I need to rest much longer than normal between sets to recover from the previous set, I do so. Finally, as a last resort, if I abandon a final set because the session has turned to crap, I’ll get it in later that day, or the next day. I’ll chase the numbers as hard as I can to attain them and exhaust every option to do so. I’m fully aware that not everyone shares the convenience of having the time, space and privacy I do. However, perhaps you can find some middle ground and use what I’ve outlined here for your own applications: are your deadlifts feeling like crap after squats and bench? Push them back a day if your schedule allows it. Getting fatigued between sets, and don’t have enough time to take long rests and complete your accessories? Shift the accessories to another session and take the rest you need to complete all of main lift volume.
One final note is that this very much applies to your main lifts. The secondary work and very few bodybuilding items that I have are not nearly as intimidating, exhausting and to be honest as important. I can hold off on progression for one week and repeat the same load and total reps that I did the previous week if need be on an accessory movement. I can also dump some of the least important accessories if it’s a deload or taper week. However, when it comes to those all-important competition lifts, I really battle to meet the numbers. I’m not always successful, but I am 95% of the time and in no small part this is due to my tactical decisions about timing, resting and organizing my schedule. Trust me when I am successful and the numbers and the training feels like I’m in a fight for my life, it sure does feel good to overcome it and meet the prescription.