Sleep quality and high intensity interval training at two different times of day: A crossover study on the influence of the chronotype in male collegiate soccer players

The influence of the chronotype on the sleep quality in male collegiate soccer players in response to acute high intensity interval training (HIIT) performed at two different times of day was evaluated. The sleep quality was poorer in the morning-type than in the evening-type players after the evening HIIT session, whereas no significant changes in the sleep quality of the two chronotypes after the morning HIIT session was observed. The results suggest that an athlete’s chronotype should be taken into account when scheduling training sessions and to promote faster recovery processes.     

Narrow-band ultraviolet B (NB UV-B) exposures improve mood in healthy individuals differently depending on chronotype

ABSTRACT

The evening chronotype is associated with psychological symptoms such as depressed mood, while skin exposure to ultraviolet radiation (UVR) may affect mood and behavior through neural and humoral routes. This pilot study aimed to investigate the impact of whole-body narrow-band (NB) UV-B exposure on current mood state and circulating 25-hydroxyvitamin D3 (25(OH)D₃), interleukin-6 (IL-6), cortisol and β-endorphin (β-END) levels in healthy participants. Here, eleven healthy women received full-body NB UV-B exposures on four afternoons, and the chronotype was assessed with a shortened version of Horne and Östberg’s Morningness-Eveningness Questionnaire (MEQ). Perceived mood was evaluated using the Visual Analogue Scale (VAS), and serum 25(OH)D₃, IL-6, cortisol and β-END concentrations were monitored daily. Decreasing VAS values showed mood to improve significantly over the five days after the four suberythematous NB UV-B exposures (p = .038), and the more the circadian preference was inclined toward eveningness, the greater the improvement in the mood dimension of wellbeing (p = .021). Baseline mood state was correlated with baseline 25(OH)D₃ (r = ?0.54, 95% CI: ?0.86 to ?0.09) and with baseline cortisol (r = ?0.57, 95% CI: ?0.87 to ?0.04). During the NB UV-B exposures, 25(OH)D₃ increased significantly, as expected, and IL-6 declined significantly by ?0.35 (95% CI: ?0.69 to ?0.07) pg/mL from the initial values of 1.12 ± 0.66 pg/mL (p = .025). In conclusion, in our pilot study, NB UV-B exposure improved mood, especially among those with evening preference for their daily activities, as well as circulating 25(OH)D₃ levels, whereas circulating IL-6 levels decreased.

Abbreviations: UVR: Ultraviolet radiation; NB UV-B: narrow-band UV-B; VAS: Visual Analogue Scales; β-END: β-endorphin; IL-6: Interleukin-6     

Effect of time of day on line-bisecting performance in female soccer players

The purpose of this study was to examine the effect of time of day on visuospatial attention in trained subjects. We used the line-bisecting task. The protocol involved 30 healthy volunteer female soccer players (age: 21.1 ± 2.1 years, level of experience: 8.1 ± 3.2 years, height: 1.7 ± 0.03 cm, weight: 59.2 ± 3.49 kg). They performed two-test sessions at different times of day, 8:00 am and 8:00 pm. The results showed a significant time-of-day effect on line-bisecting performance, with a better precision in the evening than in the morning. The rightward error observed in the morning was reversed in the evening. An interaction between time of day x length was also observed, indicating that the difference in performance between the morning and the evening increased with the length of the line. We conclude that activities that require better visuospatial performance should be programed to take place in the evening.     

The effects of sleep deprivation and time of day on cognitive performance

The extent to which the diurnal fluctuations of different cognitive processes could be affected by sleep loss may be explored to predict performance decrements observed in the real world. Twenty healthy male subjects voluntarily took part in 8 test sessions at 06:00, 10:00, 14:00, and 18:00 h, following either a night with or without sleep in random order. Measurements included oral temperature, simple reaction time, sign cancelation, Go/NoGo, and the Purdue pegboard test. The results indicate that simple reaction time and motor coordination had morning–afternoon variations closely following the rhythms of temperature and vigilance. Inhibitory attention (Go/NoGo) presented no morning–afternoon variations. Sleep deprivation may affect the profiles of cognitive performance depending on the processes solicited. Sustained and inhibitory attention are particularly affected in the morning (after 24 and 28 waking hours), while a complex task (visuo-motor coordination) would be affected after 32 waking hours only.     

Effect of chronotype on emotional processing and risk taking

There is increasing evidence to suggest that late chronotypes are at increased risk for depression. The putative psychological mechanisms underpinning this risk, however, have not been fully explored. The aim of the present study was to examine whether, similar to acutely depressed patients and other “at risk” groups, late chronotype individuals display biases in tasks assaying emotional face recognition, emotional categorisation, recognition and recall and attention. Late chronotype was associated with increased recognition of sad facial expressions, greater recall and reduced latency to correctly recognise previously presented negative personality trait words and reduced allocation of attentional resources to happy faces. The current results indicate that certain negative biases in emotional processing are present in late chronotypes and may, in part, mediate the vulnerability of these individuals to depression. Prospective studies are needed to establish whether the cognitive vulnerabilities reported here predict subsequent depression.     

An integrative and functional framework for the study of animal emotion and mood

A better understanding of animal emotion is an important goal in disciplines ranging from neuroscience to animal welfare science. The conscious experience of emotion cannot be assessed directly, but neural, behavioural and physiological indicators of emotion can be measured. Researchers have used these measures to characterize how animals respond to situations assumed to induce discrete emotional states (e.g. fear). While advancing our understanding of specific emotions, this discrete emotion approach lacks an overarching framework that can incorporate and integrate the wide range of possible emotional states. Dimensional approaches that conceptualize emotions in terms of universal core affective characteristics (e.g. valence (positivity versus negativity) and arousal) can provide such a framework. Here, we bring together discrete and dimensional approaches to: (i) offer a structure for integrating different discrete emotions that provides a functional perspective on the adaptive value of emotional states, (ii) suggest how long-term mood states arise from short-term discrete emotions, how they also influence these discrete emotions through a bi-directional relationship and how they may function to guide decision-making, and (iii) generate novel hypothesis-driven measures of animal emotion and mood.     

The synchrony effect revisited: chronotype,time of day and cognitive performance in a semantic analogy task

ABSTRACT

The synchrony effect (i.e. superior performance at optimal, inferior performance at suboptimal times of day) has been broadly studied within the context of circadian rhythms. Whether one chronotype copes better with the synchrony effect than the other received only insufficient empirical attention. We report on an applied experimental study investigating the impact of chronotype on the synchrony effect in a semantic analogy task. To detect an analogy, 36 participants (12 males) aged between 18 and 40 had to decide whether the relation between events of a source pair was mirrored by the relation between events of a target pair (e.g. to cook: to eat = to saddle: to ride). Temporal orientation of the relation within each event pair was varied corresponding either to the chronological or reverse order. Response times (RTs), error rates, as well as the psychophysiological parameters pre-experimental pupil baseline and peak pupil dilation replicate findings of a synchrony effect (shorter RTs and allocation of less cognitive resources at optimal times of day) and show an impact of chronotype (morning types generally outperforming evening types). Most importantly, morning types appeared to cope better with the synchrony effect than evening types: At suboptimal times, morning types solved the analogy detection task more efficient; that is faster with the same accuracy and without the investment of more cognitive resources. They also showed greater alertness and wakefulness indexed by greater pre-experimental pupil baselines. At optimal times of day, morning types have more cognitive resources available to allocate these to the more demanding conditions to outperform evening types. We interpret these findings to suggest that morning types are more able to adapt to unfavourable circumstances (for instance, by avoiding wasteful resource allocation when there are less cognitive resources available). Evening types appear less able to adapt to suboptimal times than morning types, because they have to deal with social jetlag and decreased self-control.     

Time of day difference in postprandial glucose and insulin responses: Systematic review and meta-analysis of acute postprandial studies

ABSTRACT

Current dietary trends show that humans consume up to 40% of their energy intake during the night. Those who habitually eat during the night are observed to have an increased risk of metabolic conditions such as type-2 diabetes and cardiovascular disease. Increasing evidence suggest that a biological consequence of eating during the night is a larger postprandial glucose response, compared to meals eaten earlier in the day. However, findings from individual acute postprandial studies have been inconsistent, due to variations in protocols. Therefore, this review aimed to systematically summarize findings from acute postprandial studies and investigate whether postprandial glucose and insulin response at night differs to during the day in healthy adults. This would indicate a possible physiological mechanism linking habitual nighttime eating and increased risk of metabolic conditions. Seven electronic databases were searched in February 2018. Included studies met the following criteria: had a day-time test between 0700 – 1600h, a nighttime test between 2000 and 0400h, the test meals were identical and consumed by the same participant at both day and night time points, preceded by a 3-h fast (minimum). Primary outcome measures were postprandial glucose and insulin incremental area under the curve (iAUC) or area under the curve (AUC). Studies that reported numerical data were included in the meta-analyses, conducted using Stata statistical software (version 13.0, StataCorp, College Station, TX, USA). For eligible studies that did not report numerical data, their authors’ conclusions on the effect of time of day on the primary outcome measures were summarized qualitatively. Full text of 172 articles were assessed for eligibility. Fifteen studies met the eligibility criteria, ten of which were included in the meta-analyses. Meta-analysis for glucose showed a lower postprandial glucose response in the day compared to during the night, after an identical meal (SMD = ?1.66; 95% CI, ?1.97 to ?1.36; p < .001). This was supported by the findings from included studies ineligible for meta-analysis. Meta-analysis also showed a lower postprandial insulin response in the day compared to during the night (SMD = ?0.35; 95% CI, ?0.63 to ?0.06; p = .016). However, findings from included studies ineligible for meta-analysis were inconsistent. Our results suggest poor glucose tolerance at night compared to the day. This may be a contributing factor to the increased risk of metabolic diseases observed in those who habitually eat during the night, such as shift workers.     

Exploring the effect of chronotype on hippocampal volume and shape: A combined approach

Current evidence suggests that acute depression is associated with reduced total hippocampal volume and regional atrophy. Here, using structural magnetic resonance imaging, we assayed linear effects of chronotype on total hippocampal volume and morphology. Later chronotype was associated with localised atrophy in the subiculum region of the right hippocampus in the absence of changes in total volume. The hippocampus forms a key node in a network of brain regions implicated in emotional regulation and alterations in the structure of this region may underpin, in part, the increased vulnerability for depression in late chronotype individuals.     

Multilevel modeling of chronotype and weekdays versus weekends to predict nonrestorative sleep

Nonrestorative sleep, a form of subjective sleep disturbance that has been largely neglected in the literature, is newly accessible to researchers via the validated restorative sleep questionnaire (RSQ). The daily version of the RSQ allows for analysis of within-subjects variation in restorative sleep across repeated samplings, and such day-to-day regularity in sleep variables has been highlighted as an important new direction for research. The present study used a sophisticated statistical approach, multilevel modeling, to examine the contributions of circadian chronotype, calendar day of questionnaire completion (weekends versus weekdays), and their interaction in explaining both interindividual and intraindividual variance in restorative sleep. Analyses were conducted using an archival dataset of college undergraduates who continuously completed daily RSQs over a 14-day sampling period. In the final multilevel model, possessing an evening type predicted lower restorative sleep between subjects, while sampling on weekdays predicted lower restorative sleep within subjects. Furthermore, a cross-level interaction was observed, such that the difference in restorative sleep on weekends versus weekdays was more pronounced among those with greater evening circadian preference. All of the effects were maintained after accounting for the significant influence of gender (women had less restorative sleep than men). These results are theoretically consistent with findings that evening types display stronger disparities in sleep schedules across free and workdays (i.e., social jet lag), and attest to the usefulness of multilevel models for statistically investigating how stable traits interact with factors that vary day to day (e.g., work or school schedules) in influencing sleep outcomes.     

Economic decision-making in morning/evening-type people as a function of time of day

Decision-making is affected by psychological factors like emotional state or cognitive control, which may also vary with circadian rhythmicity. Here, we tested the influence of chronotype (32 morning-type versus 32 evening-type) and time of day (9 a.m. versus 5 p.m.) on interpersonal decision-making as measured by the Ultimatum Game. Participants had to accept or reject different economic offers proposed by a virtual participant. Acceptance involved distribution of gains as proposed, whereas rejection resulted in no gain for either player. The results of the game showed a deviation from rational performance, as participants usually rejected the unfair offers. This behaviour was similar for both chronotype groups, and in both times of day. This result may reflect the robustness of decision-making strategies across standard circadian phases under ecological conditions. Furthermore, morning-types invested more time than evening-types to respond to high-uncertainty offers. This more cautious decision-making style of morning-types fits with our finding of higher proactive control as compared to evening-types when performing the AX-Continuous Performance Task. In line with the literature on personality traits, our results suggest that morning-types behave with more conscientiousness and less risk-taking than evening-type individuals.     

Core temperature response to cycling exercise: Effect of time of day and measurement site

This study evaluated the effect of time of day and temperature measurement site on core temperature response to exercise. Six trained cyclists performed a 1 h cycling exercise at a fixed power-output of 160 W in a controlled environment (ambient temperature of 21.5±1.6 °C and relative humidity of 31±6%) at batyphase +2 h (08:00 h) and acrophase +2 h (20:00 h) of their estimated circadian temperature rhythm; corresponding respectively to the heat gain and heat loss mode phases. Throughout the exercise, rectal and gastro-intestinal temperature data were collected. A two-way ANOVA was applied and a common nonlinear logistic-type function dependant on three parameters (asymptote, xmid and scale) was used to fit collected data. ANOVA only indicated a time of day effect without interaction with exercise duration. A nonlinear mixed-effect model allowed further analysis of temperature kinetics. The model indicated a higher theoretical increase in temperature at the end of morning exercise compared to the evening session. However, the circadian difference observed at rest persists throughout the exercise. Theoretical asymptotic temperature values at the end of the exercise and scale values (inversely proportional to the slope) are higher for the rectal measurement site than for the gastro-intestinal measurement. The model proposed offers a solution for refining the study of individual core temperature response to prolonged exercise. The main advantage is that it takes into consideration intra- and inter-individual variability in temperature kinetics.     

Nonfunctional alleles of long‐day suppressor genes independently regulate flowering time

Due to the remarkable adaptability to various environments, rice varieties with diverse flowering times have been domesticated or improved from Oryza rufipogon. Detailed knowledge of the genetic factors controlling flowering time will facilitate understanding the adaptation mechanism in cultivated rice and enable breeders to design appropriate genotypes for distinct preferences. In this study, four genes (Hd1, DTH8, Ghd7 and OsPRR37) in a rice long‐day suppression pathway were collected and sequenced in 154, 74, 69 and 62 varieties of cultivated rice (Oryza sativa) respectively. Under long‐day conditions, varieties with nonfunctional alleles flowered significantly earlier than those with functional alleles. However, the four genes have different genetic effects in the regulation of flowering time: Hd1 and OsPRR37 are major genes that generally regulate rice flowering time for all varieties, while DTH8 and Ghd7 only regulate regional rice varieties. Geographic analysis and network studies suggested that the nonfunctional alleles of these suppression loci with regional adaptability were derived recently and independently. Alleles with regional adaptability should be taken into consideration for genetic improvement. The rich genetic variations in these four genes, which adapt rice to different environments, provide the flexibility needed for breeding rice varieties with diverse flowering times.     

Time of day effect on balance performance,functional capacities and risk of fall in women with rheumatoid arthritis

ABSTRACT

Objective: This study explored the time of day effect of balance performance, functional capacities and risk of fall in three different times in patients with rheumatoid arthritis (RA) and the association between these variations and those of RA symptoms.

Methods: A “discontinual” protocol, composed of three test sessions, carried out at 6 am, 2 pm and 10 pm was set up, in order to investigate the time of day effect of balance performance, functional capacities, risk of fall, stiffness, range of motion, swollen and painful joints in women with RA.

Results: Time Up and Go Test (TUGT), Functional Reach Test (FRT) and tinetti test scores were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. Stiffness, range of motion, swollen and painful joints values were significantly higher (p < .01) at 6 am and at 10 pm compared to 2 pm. A significant difference was observed on the stiffness, range of motion and swollen joints values between 6 am and 10 pm that were higher at 6 am (p < .05).

Using Pearson’s coefficient, correlations were found between RA symptom values; and TUGT, FRT and Tinetti test scores.

Conclusion: Results showed a time of day effect of balance performance, functional capacities and risk of falls in women with RA. This variation indicates an alteration of performance at 6 am and 10 pm. Fluctuations of stiffness, limited range of motion, swollen and painful joints noted are concomitant to those of balance performance, functional capacities, and risk of fall.

Abbreviations: RA: rheumatoid arthritis; H&O questionnaire: Horne and Ostberg questionnaire; PSQI: Pittsburgh sleep quality index; HAQ: health assessment questionnaire; SF-36: the short form-36; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; TUGT: Time Up and Go Test; FRT: Functional Reach Test     

The effect of strength training by electrostimulation at a specific time of day on immune response and anaerobic performances during short-term maximal exercise

The aim of this study was to evaluate the effect of electrostimulation strength training (ES) and time-of-day on immune response and anaerobic performances during short-term maximal exercise. In randomized order, 24 active men divided into three groups: MTG (n=8): training times 07:00–08:00h; ETG (n=8): training times 17:00–18:00h; and CG (n=8) and were asked to perform a 30-s Wingate test (i.e. peak (PP), mean (MP)) and strength (1-RM) before (T0) and after four weeks of training (T1) at 08:00h and 18:00h. Our results showed that oral temperature, PP (p<0.05), MP (p<0.05), and Interleukine-6 levels (IL-6) (p<0.001) were significantly higher at 18:00h compared to 08:00h in all groups. However, 1-RM was not affected by the time-of-day (p>0.05). Likewise, IL-6 increased after exercise at T0 and T1 in CG, ETG, and MTG (p<0.001). Moreover, ES training leads an improvement in performances (p<0.05) with an increase in the tight circumference for the MTG (p<0.01) at the same time-of-training (08:00h) without affecting the immune response (p>0.05). In fact, the amplitude of variation was disappeared in MTG after ES. However, the ES did not affect the PP, MP, and 1-RM in ETG with no change in the tight circumference. A significant increase in IL-6 at the same time-of-training (p<0.05) was observed on ETG. For CG, no significant change was observed after ES compared with pre-training. In conclusion, ES training in the morning is a potent strategy to counteract the decrease in anaerobic performances without affecting inflammatory response compared to the evening training.     

Chronotype,gender, and time for sex

The study aimed at testing chronotype and gender differences in the time of day when humans feel the greatest need for sex and the time of day they actually undertake sexual activity. A Polish sample of 565 participants aged between 18 and 57 was tested. In females, regardless of chronotype, the greatest need for sex occurred between 18:00 and 24:00, but a secondary peak appeared only in morning types at 6:00–9:00. In males, the greatest need for sex occurred either in the morning or evening hours: in evening types at 9:00–12:00 and 18:00–3:00; in neither types at 6:00–9:00 and 18:00–24:00; in morning types at 6:00–12:00 and 18:00–24:00. Considering time of day when subjects were undertaking sexual activity most frequently, this appeared between 18:00 and 24:00 for all the participants, and prolonged until 3:00 at night in evening type males. Morningness preference was more strongly related to the timing of need for sex than to the timing of actual sexual activity (r?=??0.275 vs. r?=??0.174), while the timing of desire and the timing of sexual activity were positively, but moderately related (r?=?0.320).     

Effects of functional training of dysphagia to prevent pneumonia for patients on tube feeding

Objective: The purpose of this study was to evaluate the effects of functional training on outbreak frequency of pneumonia for the elderly dysphagia patients who were being tube fed. Methods: Subjects were divided into two groups; one group (n = 10) received oral care (i.e. non‐training group) and the other group (n = 11) received functional training of dysphagia in addition to oral care (i.e. training group). The dental health team treated subjects once a week for 3 years (1999–2001). The frequency of pneumonia outbreaks and changes in activities of daily living scale (ADL) were evaluated for each year. Result: It was recognised that the frequency of pneumonia in the training group decreased year by year (p < 0.05). Cognitive items in ADL improved in two subjects of the training group. No statistical differences were recognised in the non‐training group. Conclusion: It was suggested that once‐a‐week functional training of dysphagia with professional oral care might be effective in preventing pneumonia for elderly people who were being tube fed.     

The effect of time of day and recovery type after a football game on muscle damage and performance in anaerobic tests on young soccer players

The purpose of this study was to investigate the effect of time of day and different modalities of recovery (active vs. passive recovery) after intermittent exercise in young soccer players. In randomized order, 16 boys participated in the study, divided into two groups: passive recovery (PRG, n?=?8) and active recovery (ARG, n?=?8). Both groups performed tests at 07:00 and 17:00 h. The results showed that performance in the Sargent jump test (SJT), 10-m sprint, and agility were higher in the evening (17:00 h), around the presumed peak of body temperature. SJT and agility performance decreased after the match. The better performance in SJT and agility were found in ARG rather than PRG (p?p?p?p?p?p?相似文献   

Why migrate during the day: a comparative analysis of North American birds

Migration can take place primarily during the day or at night, or during both depending on the species. Why the timing of migration varies among species has been the object of much research but the underlying ecological processes are still unclear. Proximally, migration timing may be influenced by the timing of other activities or may be more prevalent in species that migrate over long distances. Adaptive scenarios emphasize the reduction in flight costs at night especially in smaller species and the advantages of travelling in groups during the day to locate staging sites more efficiently. I used phylogenetic independent contrasts to examine these hypotheses in all North American nesting birds. I uncovered 24 evolutionary transitions in migration timing, most of which involved a switch from nocturnal to diurnal migration. Few of these transitions involved a concomitant change in the timing of foraging habits or migration distance. However, species in diurnal clades were larger, travelled in larger flocks and were generally more sociable than their nocturnal counterparts. The results support the hypotheses that a reduction in flight costs and the ability to pool information from companions are associated with migration timing in North American bird species.     

Hormonal and metabolic responses to exercise across time of day and menstrual cycle phase

Galliven, E. A., A. Singh, D. Michelson, S. Bina, P. W. Gold, and P. A. Deuster. Hormonal and metabolic responses to exercise across time of day and menstrual cycle phase.J. Appl. Physiol. 83(6):1822-1831, 1997.Two studies, each utilizing short-term treadmillexercise of a different intensity, assessed the metabolic and hormonalresponses of women to exercise in the morning (AM) and late afternoon(PM). In study 1, plasmaconcentrations of growth hormone, arginine vasopressin, catecholamines,adrenocorticotropic hormone, cortisol, lactate, and glucose weremeasured before, during, and after high-intensity exercise (90%maximal O₂ uptake) in the AM andPM. In study 2, plasma concentrationsof adrenocorticotropic hormone, cortisol, lactate, andglucose were measured before, during, and aftermoderate-intensity exercise (70% maximalO₂ uptake) in the AM and PM in thefollicular (days 3-9), midcycle (days 10-16), and luteal(days 18-26) phases of themenstrual cycle. The results of studies1 and 2 revealed nosignificant diurnal differences in the magnitude of responses for anymeasured variable. In addition, study2 revealed a significant time-by-phase interaction forglucose (P = 0.014). However, netintegrated responses were similar across cycle phases. These datasuggest that metabolic and hormonal responses to short-term,high-intensity exercise can be assessed with equal reliability in theAM and PM and that there are subtle differences in blood glucoseresponses to moderate-intensity exercise across menstrual cycle phase.