Doherty · Nutrients 2023 · single-arm pre-post intervention study · n=?

The Impact of Kiwifruit Consumption on the Sleep and Recovery of Elite Athletes.

Level 4 - case-series / case-control

Uncontrolled single-arm pre-post intervention study without a comparator group

PubMed 37242157 · doi:10.3390/nu15102274 · record verified 2026-08-26

What was done

Following a 1-week baseline assessment, elite athletes consumed two medium-sized green kiwifruit (Actinidia deliciosa) one hour before bedtime nightly for 4 weeks. Sleep parameters and recovery-stress balance were evaluated using a questionnaire battery completed at baseline and post-intervention, along with daily sleep diaries maintained throughout the study period.

What was found

The abstract reports no numerical values, effect sizes, or exact p-values. It reports statistically and clinically significant improvements from baseline to post-intervention in Pittsburgh Sleep Quality Index (PSQI) global and component scores, reductions in general and sport-specific stress scales, increases in total sleep time and sleep efficiency percentage, and reductions in the number of awakenings and wake time after sleep onset.

Why it matters

This study explores whole-food nutritional strategies to support sleep hygiene and recovery in elite athletes without pharmacological sleep aids.

Limits

The lack of a control or placebo group means observed improvements cannot be separated from placebo effects, seasonal variation, or training cycle fluctuations. The abstract omits sample size, participant demographics, and numerical data. Sleep and recovery metrics were purely subjective, without objective validation from actigraphy or polysomnography.