Protein intake in inhabitants with regular exercise is associated with sleep quality: Results of the Shika study

PLoS One. 2021 Feb 26;16(2):e0247926. doi: 10.1371/journal.pone.0247926. eCollection 2021.


Study objectives: Although associations between sleep quality and environmental factors and nutrient intake have been reported, interactions between these factors have not been elucidated in detail. Therefore, this cross-sectional study examined the effects of regular exercise and nutrient intake on sleep quality using the Pittsburgh Sleep Quality Index (PSQI), which is the most frequently used index for sleep evaluation.

Methods: The participants included 378 individuals aged 40 years or older living in Shika Town, Ishikawa Prefecture. Of these individuals, 185 met the inclusion criteria. The participants completed a self-administered questionnaire assessing lifestyle habits and frequency and duration of exercise, the PSQI, and the brief-type self-administered diet history questionnaire (BDHQ) on nutrient intake.

Results: A two-way analysis of covariance on regular exercise and PSQI scores indicated that protein intake (17.13% of energy) was significantly higher in the regular exercise and PSQI ≤10 groups than in the non-regular exercise or PSQI ≥11 groups (p = 0.002). In a multiple logistic regression analysis with PSQI scores (≤10 and ≥11), protein intake was a significant independent variable in any of the models adjusted for confounding factors such as age, sex, body mass index, current smoker, and current drinker (OR: 1.357, 95% CI: 1.081, 1.704, p = 0.009) in the regular exercise group but not in the non-regular exercise group.Conclusions We identified a positive relationship between sleep quality and protein intake in the regular exercise group. These findings suggest that regular exercise at least twice a week for 30 minutes or longer combined with high protein intake contributes to good sleep quality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Body Mass Index
  • Cross-Sectional Studies
  • Diet, High-Protein*
  • Eating / physiology*
  • Energy Intake / physiology*
  • Exercise / physiology*
  • Female
  • Health Surveys
  • Humans
  • Life Style
  • Male
  • Middle Aged
  • Risk Factors
  • Sleep / physiology*
  • Sleep Wake Disorders / prevention & control

Grants and funding

The present study was supported by a Grant-in-Aid for Scientific Research (B) by the Ministry of Education, Culture, Sport, Science and Technology (MEXT), number 15H04783 and 16H03245. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.