Increasing rest intervals between resistance training sets enhances total training tonnage, leading to greater accumulation of mechanical tension and a stronger hypertrophic stimulus.

Study: Increased Neuromuscular Activity, Force Output, and Resistance Exercise Volume When Using 5-Minute Compared with 2-Minute Rest Intervals Between the Sets

Longer breaks between weightlifting sets let you lift more total weight because your muscles get more time to recover. This study found that with 5-minute breaks, people could do more work and maintain more strength than with only 2-minute breaks, which supports the idea that longer rests help build more muscle.

Study: Time under tension and mechanical variables in the bench press exercise at different rest intervals

Longer breaks between weightlifting sets let people do more reps and lift more total weight, which puts more stress on the muscles—this is how muscles get bigger.

Study: The Effect of Resistive Exercise Rest Interval on Hormonal Response, Strength, and Hypertrophy With Training

People who rested longer between weightlifting sets grew their muscles more than those who rested briefly, even though both groups got equally stronger. This suggests taking more time to recover between sets helps muscles grow bigger.

Study: Give it a rest: a systematic review with Bayesian meta-analysis on the effect of inter-set rest interval duration on muscle hypertrophy

The study found that resting longer between sets doesn’t really help you build more muscle than resting a bit shorter — and it might even mean you do fewer reps, which could hurt muscle growth. So, the idea that longer rests make you grow more by increasing effort doesn’t hold up.