Best Time of Day for Strength and Endurance Training to Improve Health and Performance? A Systematic Review with Meta-analysis

Fabienne Bruggisser; Raphael Knaier; Ralf Roth; Wei Wang; Jingyi Qian; Frank A J L Scheer

doi:10.1186/s40798-023-00577-5

Best Time of Day for Strength and Endurance Training to Improve Health and Performance? A Systematic Review with Meta-analysis

Sports Med Open. 2023 May 19;9(1):34. doi: 10.1186/s40798-023-00577-5.

Authors

Fabienne Bruggisser^#¹, Raphael Knaier^#^{2

3}, Ralf Roth¹, Wei Wang^{4

5}, Jingyi Qian^#^{4

6}, Frank A J L Scheer^#^{7

8}

Affiliations

¹ Department of Sport, Exercise and Health, Faculty of Medicine, University of Basel, Basel, Switzerland.
² Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA. raphael.knaier@unibas.ch.
³ Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Department of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA. raphael.knaier@unibas.ch.
⁴ Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.
⁵ Division of Sleep and Circadian Disorders, Department of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA.
⁶ Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Department of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA.
⁷ Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA. fscheer@bwh.harvard.edu.
⁸ Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Department of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA. fscheer@bwh.harvard.edu.

^# Contributed equally.

Abstract

Background: Current recommendations for physical exercise include information about the frequency, intensity, type, and duration of exercise. However, to date, there are no recommendations on what time of day one should exercise. The aim was to perform a systematic review with meta-analysis to investigate if the time of day of exercise training in intervention studies influences the degree of improvements in physical performance or health-related outcomes.

Methods: The databases EMBASE, PubMed, Cochrane Library, and SPORTDiscus were searched from inception to January 2023. Eligibility criteria were that the studies conducted structured endurance and/or strength training with a minimum of two exercise sessions per week for at least 2 weeks and compared exercise training between at least two different times of the day using a randomized crossover or parallel group design.

Results: From 14,125 screened articles, 26 articles were included in the systematic review of which seven were also included in the meta-analyses. Both the qualitative synthesis and the quantitative synthesis (i.e., meta-analysis) provide little evidence for or against the hypothesis that training at a specific time of day leads to more improvements in performance-related or health-related outcomes compared to other times. There was some evidence that there is a benefit when training and testing occur at the same time of day, mainly for performance-related outcomes. Overall, the risk of bias in most studies was high.

Conclusions: The current state of research provides evidence neither for nor against a specific time of the day being more beneficial, but provides evidence for larger effects when there is congruency between training and testing times. This review provides recommendations to improve the design and execution of future studies on this topic.

Registration: PROSPERO (CRD42021246468).

Keywords: Cardiovascular; Chronotype; Circadian; Diurnal; Endurance; Meta-analysis; Metabolic; Performance; Strength; Systematic review.

Publication types

Systematic Review

Abstract

Publication types

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