0 Effects of Rest Intervals Between Sets

Effects of Rest Intervals Between Sets
by Mark David

Rest Intervals should be 30 seconds to 5 minutes. True or False? I’m sure by now you are well aware that rest intervals for weight training workouts are just another variable you can manipulate depending on your overall objective (strength, muscle growth, endurance). What you may not be aware of is that what rest intervals between sets to use for those workouts and the overall important of rest intervals in determing the outcome of your sets. Here’s the scoop…


Fixed Work to Recovery Rest Intervals

You’ve probably been told to take 60 seconds of rest between sets maybe a bit more and as you get more advanced, you take less rest towards 30 seconds to make the workout more intense. While it can be that easy for a particular workout routine, your rest intervals really depend on several factors such as:

-weight being used
-goal of the training plan (strength, hypertrophy, endurance)
-type of strength being sough after
-explosiveness of the exercises

Taking a mere 30 seconds of rest for a force and power generating style of training workout would be mistake and lend itself to sub-optimal training results. Taking 3 minutes rest between TRX exercises (not rounds) is sub-optimal as well. Tossing a random number is great for the general population but when it comes to YOUR training, you need to know what the rest interval between sets in weightlifting should be to obtain maximum results.

Ideal Rest Intervals Between Sets

Your goal of any rest interval is to generate enough ATP (adenosine triphosphase) to get most of your strength back to complete the next set properly. In about 30 seconds of rest, 70% of ATP has been restored. You won’t get near complete ATP regeneration until about 3 to 5 minutes of rest (useful for maximum lift attempts).
After about 2 minutes, you can get 84% of your ATP stores returned and 4 minute rest intervals can get your closer to 89%. Somewhere about 8 minutes you’ll get complete restoration.

High Volume Training vs. Maximum Lifts vs. Muscular Endurance

Taking this into account, you should see that if you are doing high volume training, less than 1 minute probably isn’t enough rest between sets to allow enough restoration to do another set with an adequate training load. If you are doing force and power generating type lifts, 85% of your 1 rep maximum, 2 to 5 minutes is better suited for regeneration. If you choose not to rest longer while doing heavy lifts, you can lose approximately 12% to 44% of that force and power generating capacity!

All this means if that if your goal is heavy lifting, somewhere in the range of 2 to 5 minute rest intervals are optimal. That doesn’t mean you have to wait that long, but don’t be shocked when you start to feel too fatigued and weak to do the workout properly.

Short rest intervals across many sets and reps are not optimal if you are trying to maximize muscular strength and power development. Meaning, if you are doing high volume training, you’ll want at least 60 seconds to 2 minutes so you can continue to lift moderate amounts of weight.
However, if it’s muscular endurance you are after, it is almost common sense that shorter rest intervals would be advantageous in this training situation. In fact, some adaptations can occur with shorter rest intervals and high volume training such as:

-increases in blood flow
-buffer capacity
-mitochondrial density

You know that annoying lactic acid build-up that stops you short of doing those last few reps? The burn is so bad you have to quit before it’s over? High volume, short rest intervals may increase that buffer and allow you to move moderate weight over longer periods of time. It’s why going from a regular training program to a high volume program can be a really painful experience if your buffer capacity is very low.

That being said, if you do any type of high volume training (many sets, 10+ reps per set) I’d suggest 60 second rest intervals at a minimum to generate enough ATP to perform your sets at optimal levels. Anything less and you might start off fatigued (heart rate, waste products not flushed, low strength output) to really give it your best effort.

How Rest Intervals Effect Hormone Response to Exercise

If you haven’t heard, shorter rest intervals might improve hormonal responses that are thought to be responsible for greater stimulus for hypertrophy. Specifically, weight training programs that utilize shorter rest intervals, with higher repetitions (10+) with 55%-75% weight loads, greater growth hormone is released!

However, high levels of growth hormone have been shown to be released in weight training programs that use longer rest intervals (2 to 5 minutes), compound exercises with moderate to high intensity and lower repetitions. Translation, lift heavy with sub maximal intensity and plenty of rest between sets.

What you don’t see is short rest intervals utilizing isolation movements or high repetitions with low training loads. To be even more blunt, how much growth hormone is released and how that directly translates into actual muscle growth is not known.

Shorter rest intervals as you can see don’t lead to complete recovery and generally decrease the amount of workload you can do (weight lifted; volume load). If you believe that muscular hypertrophy is the resulted of weight lifted (tonnage) then shorter rest intervals may not be optimal.

It really comes down to your ability to recover that determines your rest intervals when targeting muscular hypertrophy. If you can recover well enough to lift moderate weight loads for higher reps, then 30 seconds may be all you need. If you are not that advanced, you may need longer rest periods to move the same amount of weight.

The difference is really the training objective of the entire program down to the objective of the actual workout training session. On a heavy training day, longer rest periods of 2-5 minutes are best. If you are lifting less weight but higher repetitions, you can opt for short rest intervals IF indeed you can recover.

Predetermined Heart Rate

Instead of using fixed time periods between sets depending on the training load and objective, you can use a predetermined heart rate. One method is to set a heart rate rate of 120 to 130 beats per minute as a cutoff for the next set (muscular endurance). A second method is to set the recovery period as however long it takes to get your heart rate back to 65% of maximum.
The first of these methods is better suited for cardiovascular interval training. The second method can be used for weight training. After your set, watch your heart rate, when it gets back to 65% of your maximum, initiate the next set. As you get more advanced, your heart rate should decrease faster, and your rest times grow shorter.

The Bottom Line

If your goal is to use heavy weight (85% of maximum and higher), you’ll require longer rest periods between exercise sets in the range of 2 minutes to 5 minutes. If you are using moderate weight (55% to 85%), your rest intervals between sets can be shorter from 30 seconds to 90 seconds.

The key here is to recover the strength required to complete the next set properly.