The Science of Rest Intervals: What the 2025 Research Actually Shows

If you've spent any time in a gym, you've heard the advice: rest 2-3 minutes between sets for maximum muscle growth. The logic seems sound—longer rest lets you lift more weight, which creates more mechanical tension, which should equal more muscle.

But a 2025 systematic review and meta-analysis just turned this assumption on its head.

What the Research Found

A comprehensive meta-analysis published in 2025 examined six studies comparing rest intervals shorter than 60 seconds versus longer than 60 seconds in resistance-trained males with at least one year of experience.[^1]

The results? Trivial differences in hypertrophy (standardized mean difference = 0.08).

That's essentially zero. The researchers found that longer rest periods don't actually lead to more muscle growth compared to shorter rest periods.

Here's what the data actually showed:

| Outcome | Effect Size | Interpretation | |---------|-------------|----------------| | Hypertrophy | 0.08 | Trivial | | Strength | -0.74 | Modest favor longer rest | | Metabolic hormones | 0.11 | Negligible | | Motor unit recruitment | -0.66 | Slight favor shorter rest | | Power output | -0.64 | Favor longer rest |

Why This Matters

This finding challenges one of the most pervasive dogmas in resistance training. For years, the conventional wisdom has been:

• Short rest (30-60s) = Better for hypertrophy due to metabolic stress
• Long rest (2-3 min) = Better for strength and power

The metabolic stress argument made sense—shorter rest creates more "burn," accumulates metabolites, and leads to that swollen, pumped feeling. But the new research suggests this doesn't translate to actual muscle growth differences.

The Real Picture

Here's the nuanced reality:

• Hypertrophy is similar regardless of rest length — Both short and long rest intervals produce comparable muscle growth when volume is matched.

• Strength benefits slightly from longer rest — If your goal is maximal strength, 2-3 minute rests help you lift more weight over time.

• Shorter rest may actually recruit more muscle fibers — The meta-analysis found motor unit recruitment slightly favored shorter intervals, possibly due to the challenging nature of working with less recovery.

• Practicality matters — Shorter rest means faster workouts, which might help you train more frequently or with higher weekly volume.

What Should You Do?

Based on the current evidence, here's the practical breakdown:

Use shorter rest (30-60s) when:

• You're training for hypertrophy and want to maximize metabolic stress
• You're doing higher-rep sets (12+ reps)
• Time is limited and you want efficient workouts
• You're doing isolation exercises

Use longer rest (2-3 min) when:

• You're prioritizing maximal strength
• You're lifting heavy (below 6 reps)
• You're doing compound movements like squats and deadlifts
• Power/output is a specific goal

The Bottom Line

The 2025 meta-analysis tells us something important: rest interval matters less for hypertrophy than we thought. What matters more is:

• Total weekly volume per muscle group (10-20 sets)
• Progressive overload over time
• Training to or near failure occasionally
• Adequate protein intake (1.6-2.2g/kg bodyweight)
• Sleep and recovery

Stop stressing about the clock. If you're training hard, eating enough protein, and progressively overloading, the exact rest time between sets is a minor variable.

References

[^1]: Investigating the impact of less than or greater than 60 seconds of inter-set rest on muscle hypertrophy and strength increases in males with >1 year of resistance training experience: systematic review with meta-analysis. medRxiv, 2025. doi: https://doi.org/10.1101/2025.09.22.25336351