The human body is incredibly adaptive. You stress it with something like exercise and it quickly evolves and grows stronger to ensure it can more easily handle that same stressor the next time. The key is finding the right balance of work and recovery to stimulate the changes that you want without overdoing it. Training too little won’t provide enough stress to trigger adaptations, but training too much won’t give your body time to replenish and rebuild. The human body is amazing, but it has it’s limits. I want to go over some optimal rest recommendations to use during your workout, so you can hit your goal quickly without overtraining.
Think of the stimulus first
When it comes to figuring out how to reach your goal, you first need to know what stimulus will trigger the adaptation you need. For the most part these are obvious (to build your running endurance you need to run more), but we’re discovering that some aren’t as obvious as we once thought. A great example of this is the realization that high intensity interval training quickly improves long distance endurance. Previously we thought it was all about mileage. If you want to train for a marathon then you need to run ten miles a day. This kind of overtraining actually did work for many, but more often than not, it led to burnout and injuries. Ultimately any kind of training will cause improvements, but the wrong kind of training wastes your time. You’ll not only spend more time in the gym, but it will take you much longer to reach your goal.
Intensity trumps duration
The first thing I want to emphasize is that when it comes to training adaptations, it’s the intensity of the work set that matters most. Rest is important for proper training, but it’s purpose is to ensure that your body has recovered enough so you can give your all during your next set. Short rest breaks are fine if you’re in a hurry or want to keep your heart rate up for extra fat burning, but the long-term adaptations are triggered by the work set.
You also want to make sure the volume/duration of the work set will trigger the adaptations you want. Longer work sets will force you to reduce your intensity so you can pace yourself all the way to the end. Pacing yourself won’t work all of your energy systems and it won’t trigger the same gene expressions. You need to give yourself adequate rest so that you won’t hold back too much during your work sets.
Just because it feels harder doesn’t mean it works better
I still see this all the time with young fighters. They need to get ready for three 5-minute rounds, so to prepare, they’ll do ten 10-minute rounds. They figure working above and beyond what they need will make it easier to get through the shorter distance, but what actually happens is they pace themselves for lower intensities and aren’t ready to work at the higher intensities required for their fights.
I see the same thing with other types of high intensity training. Short and intense workouts are all the rage right now, but the rest periods are so short that people aren’t really working as intensely as they could (and should). They’re pacing themselves to make it to the end. In the article I wrote that looked at the Sleep Low training strategy, both groups of athletes did the same high intensity interval workouts, but the ones that had the greatest gains on their triathlon times were the ones that were able to work a little harder during the intense sets (because they trained their bodies to supplement their efforts with stored body fat). Even during these endurance-based events, it was the work sets that made the difference in their results.
When I refer to optimal rest below, I mean the amount of time required to help you work your hardest during your set. As I mentioned above, everything works and I personally get bored if my rest breaks are too long. I want to stress that you don’t need to look at these as rules that must be obeyed but rather guidelines to help you customize your plan to something you can stick with long-term (which matters more than anything).
Stimulus for adaptation: Training load
Optimal rest period: 2 to 5 minutes between sets
Strength training is all about teaching your muscles to work together to maximize your strength. As such, the training protocols are a little different for beginner and advanced lifters. Training your muscle fibers to work together (neuromuscular training) means you’ll exhaust your energy systems and your nervous system, and it’s the nervous system that takes a little longer to recover. Beginners should do lighter weight, about 60 percent of your 1 Rep Max (1RM) for 8 to 12 reps. Advanced lifters should increase the weight (about 80 to 100 percent of 1RM) and reduce the reps (about 1 to 8 reps). 2 minutes of rest is sufficient for beginners and can work for advanced lifters, but bumping it up to 3 minutes for advanced lifters would be ideal.
Stimulus for adaption: Progressive load
Optimal rest period: 2 to 3 minutes
Getting your muscle fibers to work together and growing new muscle fibers are actually different types of training. The benefits will cross over, but building muscle can actually be done with less weight than most people would expect. One of the most effective muscle building protocols I have found is HST (Hypertrophy-Specific Training) by Bryan Haycock. The basic idea is that increasing the load on your muscles (weight you lift) by about 5 percent every workout, stimulates muscle growth. While this sounds heavy, it actually starts out surprisingly light. You figure out your maximum weight and then work backwards to determine the weights you should use at the start of the program. You can read more about HST here if you’re interested in learning about the program. He doesn’t emphasize rest times in the plan because once again, it’s the training intensity that matters. That said, research recommends about 2 to 3 minutes between sets to maximize myofibrillar protein synthesis and intracellular signaling.
Stimulus for adaption: Lactate production
Optimal rest period: 1 to 1 ratio of high intensity training to low intensity training, or 30 seconds sprinting to 3 to 5 minutes low intensity training
As endurance improves, we develop more mitochondria (the power plants of our cells). As I mentioned in the article on lactate (commonly referred to as lactic acid), this substance isn’t actually a metabolic waste product. It’s a fast-acting fuel source that sustains us during intense activities and it’s also a signaling molecule that triggers many positive adaptations. One of these signals is for mitochondrial biogenesis (the growing of new mitochondria). This is the reason why 1 minute of intense activity improves aerobic endurance as much as 45 minutes of steady state training. The study showing these results actually broke that 1 minute down into 20 second sprint intervals on a bike interspersed with 2 minutes of low intensity cycling to recover. Other sources like the American College of Sports Medicine (ACSM) recommend rest intervals of 4 to 4.5 minutes of low intensity training after an all-out intensity work set like 30 seconds of sprinting.
It doesn’t need to be miserable to work
So why do protocols like Tabata only use 10 seconds of rest? Because like I said above, everything works, but that doesn’t mean it works best. I’ve done many Tabata workouts and I’ve led many of my clients through them as well, and I’ve found that you have to pace yourself more during the work sets in order to make it all the way through. Increasing the rest time will improve your results because you can work harder during your work sets. There hasn’t been any research testing Tabata head-to-head with longer rest periods, but there is plenty of research like the study mentioned above that’s looking for the minimum amount of effective training needed to keep people motivated to exercise. Tabata works but it’s far more unpleasant, so people don’t seem to stick with it long-term. If you enjoy it, keep going. I’m not trying to say Tabata isn’t effective, I just want people to understand they can also get fantastic results with more rest. Doing high intensity training 3 days a week triggers adaptations that will quickly improve your health, fitness and blood chemistry and these changes will aid in weight loss.