The effect of time of day and high intensity exercise on cognitive performances of elite adolescent karate athletes

To explore the effect of time of day (TOD) on several components of cognitive performance prior and post to a physically exhaustive task in a sample of adolescent elite athletes. In a counterbalanced and randomized order, fourteen highly trained male karate athletes (17 ± 0.96 years; 1.75 ± 0.07 m; 68.0 ± 9.50 kg; BMI 22.15 ± 0.54 kg.m^-2) completed two test sessions at 09h00 and 16h00. Cognitive performance was evaluated before and after the karate specific test (KST). During each session, participants completed the profile of mood state (POMS), simple (SRT) and choice (CRT) reaction times, comparison test (COMT), mental rotation test (MRT), egocentric distance estimation (DE), and the rating of perceived exertion (RPE). KST was not TOD dependent (p > .05, d = 0.33). RPE scores were higher in the afternoon compared to the morning (p < .05, d = 0.68). Before the KST, SRT (p < .01, d = 0.69), CRT (p < .01, d = 0.47), COMT (p < .01, d = 0.62) and MRT (p < .001, d = 0.65) were better in the afternoon than in the morning. However, DE was not affected by the TOD (P > .05). KST improved SRT (p < .01, d = 0.078), CRT (p < .001, d = 0.72), COMT (p < .001, d = 1.31) and MRT (p < .001, d = 0.80) performances only in the morning. Cognitive performances are TOD dependent with higher performances realized in the afternoon. Performing a high intensity exercise in the morning, but not in the afternoon, enhanced several aspects of cognitive performances. The current results indicate that an intensive warm-up could be beneficial when a morning competition requires high cognitive readiness.

Does who I am and what I feel determine what I see (or say)? A meta-analytic systematic review exploring the influence of real and perceived bodily state on spatial perception of the external environment

Background

Bodily state is theorised to play a role in perceptual scaling of the environment, whereby low bodily capacity shifts visuospatial perception, with distances appearing farther and hills steeper, and the opposite seen for high bodily capacity. This may play a protective role, where perceptual scaling discourages engaging with the environment when capacity is low.

Methodology

Our protocol was pre-registered via Open Science Framework (https://osf.io/6zya5/) with all amendments to the protocol tracked. We performed a systematic review and meta-analysis examining the role of bodily state/capacity on spatial perception measures of the environment. Databases (Medline, PsychINFO, Scopus, Embase, and Emcare) and grey literature were searched systematically, inclusive to 26/8/21. All studies were assessed using a customised Risk of Bias form. Standard mean differences and 95% CIs were calculated via meta-analysis using a random-effects model.

Results

A total of 8,034 studies were identified from the systematic search. Of these, 68 experiments (3,195 participants) met eligibility and were included in the review. These were grouped into the following categories: fatigue; pain; age; embodiment; body size/body paty size; glucose levels; fitness; and interoception, and interoceptive accuracy. We found low level evidence (limited studies, high risk of bias) for the effect of bodily state on spatial perception. There was consistent evidence that both glucose manipulations and age influence spatial perception of distances and hills in a hypothesised direction (lower capacity associated with increased distance and hill steepness). Mixed evidence exists for the influence of external loads, embodiment, body/body-part size manipulations, pain, and interoceptive accuracy. Evidence for fitness and/or fatigue influencing spatial perception was conflicting; notably, methodological flaws with fitness and fatigue paradigms and heterogenous spatial perception measures may underlie null/conflicting results.

Conclusion

We found limited evidence for bodily state influencing spatial perception of the environment. That all studies had high risk of bias makes conclusions about reported effects reflecting actual perceptual shifts (vs merely reflecting experimental demands or error due to inadequate study design) pre-emptive. Rigorous evaluation is needed to determine whether reported effects reflect more than bias (e.g., experimental demands, inadequate blinding). Future work using reliable measures of spatial perception, comprehensive evaluation of relevant confounders, and methodologically robust (and experimentally confirmed) bodily state experimental paradigms is warranted.

Melatonin supplementation improves psychomotor and physical performance in collegiate student-athletes following a sleep deprivation night

Several studies report sleep deprivation negatively impacts post-cognitive and physical performance, and other functions. Recent findings indicate ingestion of melatonin prior to exercise enhances tolerance to training and improves competition. We investigated the effects of melatonin supplementation on psychomotor performance and selected physical fitness measures of collegiate student-athletes following 4 h and 24 h of sleep deprivation. The study employed a repeated-measures, double-blind, randomized controlled protocol with posttest control group design with six conditions [3 sleep conditions (without sleep deprivation, 4 h sleep deprivation (4SD) and 24 h sleep deprivation (24SD)) × 2 supplementation conditions (melatonin and placebo)]. Ten trained male collegiate student-athletes (mean ± SD; age: 20 ± 2 y) attended the laboratory on six occasions with 72 h between successive visits. Placebo or 6 mg of melatonin were administered orally in capsules 30 min before the tests of: static and dynamic balance, reaction time, and anaerobic power. Also, blood lactate was measured before and 3 min after the anaerobic power exercise. During the placebo session, the results indicated that 4SD and 24SD had negative effect on the measured parameters, with higher impacts of the 24SD condition. Compared to placebo and during both 4SD and 24SD conditions, melatonin had a positive effect on static and dynamic balance, anaerobic power, blood lactic acid, and reaction time (p < .05). However, 6 mg melatonin ingestion had no significant effect on all dependent variables in collegiate student-athletes after the night without a sleep deprivation (p > .05). In conclusion, 6 mg of melatonin may be used by student-athletes to improve balance and psychomotor and physical performances after 4 h or 24 h of sleep deprivation.

Effect of Angle of View and Partial Sleep Deprivation on Distance Perception

The present study aimed to investigate the effects of intensive effort on egocentric distance perception according to different angles of view after sleep deprivation at the beginning (SDB) or at the end (SDE) of the night and after a normal sleep night (NNS). Ten male students soccer players (age 22.8 ± 1.3 years; body mass 72.0 ± 10.4 kg; body height 180.0 ± 3.0 cm) performed a repeated cycling (RS) exercise (10 × 6 s maximal cycling with 24 s in between) after SDB, SDE, and NNS. They were asked to estimate three distances (i.e. 15, 25, and 35 m) before and after RS from different angles of view [i.e. in front (0°) and in side (45° left and 45° right)]. For 35 m, distance estimation was better during NNS compared to SDB and SDE for the front and the two side angles either before or after RS (p < 0.05). Concerning 25 m, distance estimation was better after compared to before RS for the front angle during the NNS session (p < 0.05). For 15 m, distance estimation was better during NNS than SDB and SDE for the front and both side angles after RS (p < 0.05). We concluded that partial sleep deprivation negatively affected the estimation of the egocentric distance for the three angles of view either at rest or after RS exercise.