The effect of time of day on Special Judo Fitness Test in active judokas: Evaluation in terms of chronotype.

The present cross-sectional study aims to examine the effect of time of day on the judo-specific performance in judokas, considering their chronotypes. Twenty-four male judokas participated in the study where the Morningness-Eveningness Questionnaire was administered, and on it, they were divided into morning-type (MT:12-judokas) and evening-type groups (ET:12-judokas). Afterwards, the Special Judo Fitness Test (SJFT) was applied to both groups at three different times (morning: 09:00 h, afternoon: 13:00 h and evening: 17:00 h) with body temperature measured before and after every SJFT performance. As a result, the Group*Test Time interaction significantly affected overall throwing performance during SJFT [F(2,44) = 29.437, p = 0.001, η2p: .572]. Furthermore, a significant time effect was found for the SJFT index [F(2,44) = 5.118, p = 0.010, η2p: .189] and for the Group*Test Time interaction with the mean value of the index [F(2,44) = 24.424, p < 0.001, η2p: .526]. Furthermore, body temperature had a significant time effect [F(2,44) = 301.454, p < 0.001, η2p: .932] and the Group*Test Time interaction [F(2,44) = 5.802, p = 0.006, η2p: .209]. In conclusion, coaches and exercise experts should consider judo athletes' chronotype when planning special training programs to improve judo-specific anaerobic capacity. Furthermore, to minimize the impact of time of day and chronotype on athletes' performance in competitions, it is recommended that MT athletes develop their judo-specific anaerobic capacity in the evening hours, when their performance is lower, while ET athletes should do so in the morning hours when their performance is lower via randori training.

Effects of chronotype-tailored bright light intervention on post-treatment symptoms and quality of life in breast cancer survivors.

PURPOSE: Bright light therapy holds promise for reducing common symptoms, e.g., fatigue, experienced by individuals with cancer. This study aimed to examine the effects of a chronotype-tailored bright light intervention on sleep disturbance, fatigue, depressive mood, cognitive dysfunction, and quality of life among post-treatment breast cancer survivors. METHODS: In this two-group randomized controlled trial (NCT03304587), participants were randomized to receive 30-min daily bright blue-green light (12,000 lx) or dim red light (5 lx) either between 19:00 and 20:00 h or within 30 min of waking in the morning. Self-reported outcomes and in-lab overnight polysomnography sleep study were assessed before (pre-test) and after the 14-day light intervention (post-test). RESULTS: The sample included 30 women 1-3 years post-completion of chemotherapy and/or radiation for stage I to III breast cancer (mean age = 52.5 ± 8.4 years). There were no significant between-group differences in any of the symptoms or quality of life (all p > 0.05). However, within each group, self-reported sleep disturbance, fatigue, depressive mood, cognitive dysfunction, and quality of life-related functioning showed significant improvements over time (all p < 0.05); the extent of improvement for fatigue and depressive mood was clinically relevant. Polysomnography sleep findings showed that a number of awakenings significantly decreased (p = 0.011) among participants who received bright light, while stage 2 sleep significantly increased (p = 0.015) among participants who received dim-red light. CONCLUSION: The findings support using light therapy to manage post-treatment symptoms in breast cancer survivors. The unexpected symptom improvements among dim-red light controls remain unexplained and require further investigation. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03304587, October 19, 2017.

Chronotype is associated with addiction-like eating behavior, mindful eating and ultra-processed food intake among undergraduate students.

This study aimed to investigate the relationships between chronotype and addiction-like eating behavior, mindful eating and ultra-processed food consumption among undergraduate students. Specific and validated scales were used in order to evaluate chronotype, addiction-like eating behavior and mindful eating (N = 605). Dietary intake was determined by food frequency questionnaire and percentage energy from ultra-processed food was calculated. Self-reported weights and heights were obtained from the participants. Mean scores of scales, social jetlag, energy intake, ultra-processed food intake and BMI were compared by chronotypes. Associations between chronotype, addiction-like eating behavior, mindful eating, ultra-processed food consumption and BMI were determined by Pearson's test. The relationships between chronotype and addiction-like eating behavior, mindful eating and ultra-processed food intake were assessed by linear regression models and adjusted for sex, BMI, energy intake, season, smoking and alcohol consumption. Evening-type participants had higher scores of social jetlag (2.01 ± 0.09), appetitive drive (26.02 ± 0.63), low dietary control (20.50 ± 0.41), addiction-like eating behavior (46.52 ± 0.85), lower scores of recognition (21.91 ± 0.43) and higher percentage energy from ultra-processed food (32.24 ± 1.26%). Chronotype score showed negative associations with addiction like eating behavior (ß=-0.247, p < 0.001) and ultra-processed food consumption (ß=-0.247, p < 0.001), and a positive association with recognition (ß = 0.124, p < 0.001). Results suggest that chronotype is inversely associated with addiction-like eating behavior and ultra-processed food consumption, and positively associated with mindful eating among undergraduate students.

It's a match: The relevance of matching chronotypes for dual-earner couples' daily recovery from work.

Cohabiting dual-earner couples are increasingly common. However, previous recovery research mainly focused on employees independently of others, thereby overlooking an essential part of their life. Therefore, we take a closer look at dual-earner couples' recovery processes and link this research to a circadian perspective. We assumed that unfinished tasks impede engagement in time with the partner (absorption in joint activities, directing attention toward the partner) as well as recovery experiences (detachment, relaxation), whereas engagement in time with the partner should boost recovery experiences. Integrating a circadian perspective, we proposed that employees from couples with matching circadian preferences (chronotype) benefit more from engagement in time with their partner (i.e., stronger relationships with recovery experiences). Additionally, we explored whether a match between partners' chronotypes buffers the negative relationship between unfinished tasks and engagement in joint time. We conducted a daily diary study with 143 employees from 79 dual-earner couples, providing data on 1,052 days. A three-level path model showed that unfinished tasks were negatively related to absorption in joint activities and detachment, whereas absorption positively predicted recovery experiences. Furthermore, the couples' chronotype match mattered in the interplay with engagement in joint time: for couples with higher (vs. lower) chronotype match, experiencing detachment depended on absorption while for couples with lower (vs. higher) chronotype match, attention was even harmful for experiencing relaxation. Thus, it is crucial to consider employees' partners when investigating their recovery processes because employees cannot act independently if they also need to take their partner's circadian rhythms into account. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The relationship between chronotype, dispositional mindfulness and suicidal ideation among medical students: mediating role of anxiety, insomnia and social dysfunction.

The aim of the study was to assess whether chronotype and subjective amplitude may predict suicidal ideation independently of mindfulness, and whether anxiety/insomnia and social dysfunction may be mediators of the relationship between chronotype and suicidal thoughts among medical students. The study group comprised 600 students of the medical faculties (191 men and 409 women), with a mean (SD, range) age of 21.94 (1.81, 18-31) years. The participants completed the Chronotype Questionnaire, the Five Facet Mindfulness Questionnaire (FFMQ) and the General Health Questionnaire (GHQ-28). Two items from GHQ-28 depression scale were extracted to measure suicidal ideation. The FFMQ score correlated negatively with the suicidal ideation score. The total effect of chronotype was insignificant when controlled for FFMQ. In the case of indirect effects, subjective amplitude score predicted suicidal ideation via both anxiety/insomnia and social dysfunction scores. The FFMQ score predicted suicidal ideation only via the social dysfunction scale. The direct effect of subjective amplitude was insignificant. Our findings indicate that the flexibility (or rigidity) of circadian rhythm may be linked to the intensity of experienced suicidal ideation, but only via anxiety/insomnia and social dysfunction, independently of mindfulness and morningness-eveningness.

Regional shape alteration of left thalamus associated with late chronotype in young adults.

Chronotype reflects individual differences in circadian rhythms and influences individual psychology and behavior. Previous studies found altered subcortical structures are closely related to individual chronotypes. However, these studies have been conducted mainly using voxel-based morphometry and traditional volume measurement methods with certain limitations. This study aimed to investigate subcortical aberrant volume and shape patterns in late chronotypes (LC) young adults compared to early chronotypes (EC) young adults. Magnetic resonance imaging (MRI) scanning and chronotype assessment were performed once for all participants, including 49 LC young adults and 49 matched EC young adults. The morningness and eveningness preferences were assessed using the Chronotype Questionnaire. A vertex-wise shape analysis was conducted to analyze structural MRI data. There were no significant differences in brain tissue volume and subcortical structural volume between groups. LC young adults showed significant regional shape atrophy in the left ventral posterior thalamus compared to EC individuals. A significant correlation was found between the regional shape atrophy of left ventral posterior thalamus and the score of Chronotype Questionnaire in LC young adults. Regional shape alteration of left thalamus was closely related to the chronotype, and LC may be a potential risk factor for sleep-related behavioral and mental problems in young adults. However, the predominantly female sample and the failure to investigate the effect of chronotype on the subcortical structure-function network are limitations of this study. Further prospective studies are needed to investigate the temporal characteristics of thalamic shape changes and consequent behavioral and psychiatric problems in adults with LC.