Diurnal variation of psychomotor, cognitive and physical performances in schoolchildren: sex comparison.
Level 2 - randomized trial
Counterbalanced crossover experimental study in humans
PubMed 39415109 · doi:10.1186/s12887-024-05145-8
What was done
Thirty schoolchildren (15 girls, mean age 9.60 years; 15 boys, mean age 9.40 years) were tested across four times of day (08h00, 11h00, 14h00, and 17h00) separated by 48 hours of rest in a counterbalanced crossover design. The protocol assessed attention (digit cancellation test), mental flexibility (trail making test), jumping capability (five jump test [5JT]), upper body power (2 kg push-ball test), aerobic/anaerobic running capacity (5 m shuttle run test [5mSRT]), and rating of perceived exertion (RPE).
What was found
Mental flexibility was significantly higher at 08h00, 11h00, and 14h00 compared to 17h00 (p = 0.001). In girls, attention was significantly higher at 08h00 versus 17h00 both pre- and post-5mSRT (p = 0.001). 5JT distance was significantly lower at 17h00 compared to 08h00 (girls p = 0.02; boys p = 0.001), 11h00 (girls p = 0.004; boys p = 0.001), and 14h00 (girls p = 0.001; boys p = 0.001). Push-ball performance (p = 0.086) and 5mSRT measures (best distance p = 0.173, total distance p = 0.306, mean distance p = 0.29, fatigue index p = 0.06) showed no diurnal variation. End-test RPE was higher at 11h00 compared to 08h00 (p = 0.02) and 14h00 (p = 0.001). The abstract reported p-values without absolute performance values or effect sizes.
Why it matters
The findings suggest that cognitive tasks and lower-body explosive physical tasks in 9- to 10-year-olds may decline by late afternoon, which could inform school scheduling for academic and athletic activities.
Limits
The sample size was small (30 participants from a narrow age band), limiting generalizability to other age groups. The abstract omitted exact baseline performance means, standard deviations, and effect sizes. Environmental factors (sleep duration, nutritional timing, prior physical activity before testing sessions) were not described in the abstract.
Cited by
- context Mental and physical performance peaks approximately 3 hours and 11 hours after waking, driven by diurnal variations in body temperature and circulation.