Gym regulars know that rest times between sets are a thing of beauty, that short moment of calm and reflection. You start with deep, horrible fatigue, sitting there as your heart hammers. Gradually your breathing slows and you become mindful of your discomfort. Maybe you’re sweating, maybe your muscles are aching. About halfway through, the endorphins kick in and that ache begins to feel good—you’ve put the work in, managed the unthinkable. Then, finally, you’re feeling on top of the world and are good to go again.
Skip your rest and not only do you forgo all of that, but you’re actually short-changing gains and putting your body at risk of injury. On top of that, with some professional guidance you can manipulate rest times to your advantage. But how?
Why do we need to rest between sets?
Let’s start with the obvious. If you don’t rest between sets, there isn’t really anything delineating one set from another, so instead of four sets of ten curls, you’re doing forty more or less in one go. No one’s arms can handle that. And as the science shows, more sets are better than one.
“Rest periods are crucial,” says celebrity PT Patrick Murphy. “We aren’t building muscle in the gym, we are breaking down the fibres on a microscopic level, depleting our adenosine triphosate and phosphocreatine in the process. The rest periods help the muscles recover and replenish these energy stores, making it possible for continued optimal performance for the remainder of the workout.”
Our muscles mostly use anaerobic pathways during the most intense bouts of exercise. As you’ll remember from GCSE science, this lack of oxygen only leads to one thing. “Lactic acid and the impact that this has on your blood pH is actually a big driver in neuromuscular fatigue and a decrease in power output over the course of your workout,” explains Shaun Stafford, founder of Physique Formula and trainer to celebrities.
As well as sending more fuel to your muscles, resting also gives your aching biceps a chance to flush out burning lactate and hydrogen ions. Plow on before this happens and fatigue will set in, sinking the rest of your reps. In fact, one study suggests that, in the bench press at least, greater rest periods allow us to perform more reps in later sets.
Should my rest times depend on the workout?
While rest is important, how long you need to rest for can vary depending on exactly what you’re putting your body through.
“From a powerlifting perspective, our muscles don’t fatigue too much but our central nervous system does,” says Mikey Herrera-Castro, a PT at Gymbox Ealing. “In this instance, resting up to four minutes will give your body enough recovery to push again the next set. In bodybuilding, one-minute rests are better in order to keep the target muscle stimulated.” These findings are backed up by a study in the journal Sports Medicine.
