Pre-sleep protein supplementation after an acute bout of evening resistance exercise does not improve next day performance or recovery in resistance trained men

ABSTRACT

Background

To evaluate the effect of pre-sleep protein supplementation after an acute bout of evening resistance training on next day performance and recovery the following day in physically active men.

Methods

Eighteen resistance trained men performed a single bout of resistance exercise then received either a pre-sleep protein (PRO) supplement containing 40 g of casein protein (PRO; n = 10; mean ± SD; age = 24 ± 4 yrs; height = 1.81 ± 0.08 m; weight = 84.9 ± 9.5 kg) or a non-caloric, flavor matched placebo (PLA; n = 8; age = 28 ± 10 yrs; height = 1.81 ± 0.07 m; weight = 86.7 ± 11.0 kg) 30 min before sleep (1 h after a standard recovery drink). Blood samples were obtained pre-exercise and the following morning (+12-h) to measure creatine kinase and C-reactive protein. Visual analog scales were utilized to assess perceived pain, hunger, and recovery. One-repetition maximum (1RM) tests for barbell bench press and squat were performed pre-exercise and the following morning (+12-h). Statistical analysis was performed using SPSS (V.23) and p ≤ 0.05 was considered statistically significant.

Results

There were no significant differences between the groups in next morning performance or muscle damage biomarkers. However, pre-sleep PRO resulted in a lower perception of hunger that approached significance the following morning when compared to PLA (PRO:43.6 ± 31.2, PLA: 69.4 ± 2.22; 95% C.I. = −53.6, 2.0; p = 0.07; d = 0.95).

Conclusions

Following an evening bout of exercise, pre-sleep PRO did not further improve next morning muscle damage biomarkers or maximal strength performance in resistance trained men compared to a non-caloric PLA. However, there may be implications for lower perceived hunger the next morning with pre-sleep PRO consumption compared to PLA.

KEYWORDS:

• Protein
• timing
• pre-sleep
• athletes
• recovery
• resistance training
• strength

Acknowledgments

The authors thank the participants for their commitment and dedication to this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethics approval and consent to participate

University of KwaZulu Natal Biomedical Research Ethics Committee (REF: BFC 354/13).

Availability of data and material

The datasets during and/or analysed during the current study available from the corresponding author on reasonable request.

Authors’ contributions

MJO and AJM conceived the study idea and methods. JD collected the data and collated the datasets. JD, MJO, AJM performed the statistical analyses and data interpretation. JD, MJO, AJM drafted the manuscript. MJO, PGS, MCM, LIR, AJM revised the manuscript. All authors contributed significantly to the manuscript and approved the final version submitted for publication.

Additional information

Funding

This study was supported by Dymatize Nutrition.