Key result
Self-selected rest intervals show no benefit over fixed intervals for exercise performance.
Why the study?
Evidence regarding the acute effects of self-selected versus fixed rest intervals on exercise performance, heart rate, and blood lactate remains inconsistent.
Do self-selected rest intervals improve exercise performance, heart rate, and blood lactate compared to fixed rest intervals?
Meta-Analysis (n=281)
Do self-selected rest intervals improve exercise performance, heart rate, and blood lactate compared to fixed rest intervals?
Self-selected and fixed rest intervals produce comparable acute effects on exercise performance, heart rate, and blood lactate, though self-selected intervals may offer a small advantage when outliers are excluded.
Self-selected rest intervals match fixed ones for acute performance and responses; supports flexible, individualized prescriptions in training protocols.
Background Rest interval duration is a key variable in exercise prescription, influencing both performance and physiological responses. Traditional training typically employs fixed rest intervals; however, this approach may not adequately reflect individual variability in recovery needs. Recently, self-selected rest intervals—based on individual perception—have gained attention as a potential strategy for more precise load regulation. Nevertheless, current evidence regarding their effects on exercise performance, heart rate, and blood lactate remains inconsistent. Methods This study followed PRISMA guidelines and conducted a systematic search of Web of Science, PubMed, Cochrane Library, and Embase from database inception to March 20, 2026. Acute experimental studies comparing self-selected and fixed rest intervals were included. A three-level random-effects meta-analysis was performed to account for dependency among multiple effect sizes. Subgroup analyses, meta-regression, and sensitivity analyses were conducted to explore potential moderators and assess robustness. Results Sixteen studies (k = 16) involving 281 participants were included. No significant overall difference was observed between self-selected and fixed rest intervals for exercise performance (g = 0.27, 95% CI [−0.14, 0.69], p = 0.29), with substantial between-study heterogeneity. After removing outliers, a small but significant effect favoring self-selected rest intervals was identified (g = 0.20, 95% CI [0.08, 0.33], p < 0.01). No significant differences were observed for heart rate (g = 0.002, p = 0.98) or blood lactate (g = −0.20, p = 0.36). Conclusion Self-selected and fixed rest intervals produce comparable effects on exercise performance and physiological responses. However, self-selected rest intervals may confer a small advantage in maintaining performance under specific conditions. These findings should be interpreted with caution due to sensitivity to outliers and study heterogeneity.
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Lv et al. (2026) reported a meta-analysis. Self-selected rest intervals vs. Fixed rest intervals was evaluated on Exercise performance (g 0.27, 95% CI -0.14, 0.69, p=0.29). Self-selected rest intervals produced no significant overall difference in exercise performance compared to fixed rest intervals (g = 0.27; 95% CI -0.14 to 0.69; p=0.29).
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