Perception of effort in morning-type cyclists is lower when exercising in the morning

Circadian rhythm in sportspersons and athletic performance: A mini review

Circadian rhythms in the physiological and behavioral processes of humans play a crucial role in the quality of living and also in the magnitude of success and failure in various endeavors including competitive sports. The rhythmic activities of the body and performance in sportspersons do have a massive impact on their every cutthroat competition. It is essential to schedule sports activities and training of players according to their circadian typology and time of peak performance for improved performance and achievement. In this review, the focus is on circadian rhythms and diurnal variations in peak athletic performance in sportspersons. Accuracy and temporal variability in peak performance in an individual could be attributed to various factors, namely chronotype, time of the day, body temperature, jetlag, hormones, and prior light exposure. Circadian rhythm of mood, alertness, T-core, and ultimately athletic performance is not only affected by sleep but also by circadian variations in hormones, such as cortisol, testosterone, and melatonin. There are, however, a few reports that are not consistent with the conclusions drawn in this review. Nevertheless, circadian rhythm and performance among sportspersons and athletes are important areas of research. This review might be useful to the managers and policymakers associated with competitive sports and athletic events.

Diurnal Variation of Specific Tests' Performance and Related Psychological Aspects in Young Judo Athletes

Purpose: This study investigated the effects of time-of-day on judo athletes' performances and the associated psychological variables and perceived exertion following judo-specific tests. Methods: Twelve male judo athletes (age: 16 ± 1 years) performed in a randomized and counterbalanced order the special judo fitness test (SJFT), the judo physical fitness test (JPFT), the dynamic and isometric judogi chin-up tests in the morning (8:00 a.m), midday (12:00 p.m), and afternoon (5:00 p.m). Oral temperature and psychological variables [profile of mood state (POMS), Hooper questionnaire, total quality of recovery (TQR)] were assessed before and after the tests, and ratings of perceived exertion (RPE) and the physical activity enjoyment scale (PACES) were assessed only after the tests. Results: RPE score was higher in the morning compared to the afternoon after the JPFT (d = 0.38, p = .045). PACES after JPFT was higher in the morning compared to midday (d = 0.85, p < .001). The isometric and dynamic performances during chin-up tests were higher in the afternoon compared to the morning (d = 0.38, p = .048 and 0.047, respectively). Also, oral temperature was higher in the afternoon compared to the morning (d = 0.41, p = .050) and the midday (p = .047) for dynamic test, while TQR, well-being indices, and POMS did not differ according to time-of-day (p > .05). Conclusions: These results suggest that dynamic and isometric judo chin-up tests are time-of-day dependent with higher performance recorded in the afternoon than in the morning. However, performances in the JPFT and SJFT were not time-of-day dependent.

Chronotype and athletes’ performance in sports: A narrative review

The circadian system is managed by the suprachiasmatic nucleus, which is also called a master clock, and peripheral clocks spread all over the body. A complex system of neuronal, hormonal, and autonomous signals coordinates these clocks. However, this narrative review aimed to discuss the influence of circadian rhythms on the athlete’s performance, rate of perceived exertion, resynchronization, and aerobic and anaerobic exercise. An adequately timed wake-up is believed to play an essential role in an athlete’s performance. Based on the literature, chronotype appears to correlate with ratings of perceived exertion and fatigue scores, and morning types are less fatigued in the morning. When chronotype was evaluated, fatigue and vigor had time-by-group interactions. Swimmers with morning-type profiles showed lower fatigue scores before the (06:30 hour) time test than before the (18:30 hour) time test, while those with neither-type profiles had similar fatigue scores in both sessions. Vigor scores were also higher in the morning types than in the neither-types (17.9±7.1) before the morning test and (15.6±5.5) before the evening test. Studies have also shown that exercise enhances aerobic capacity based on the day. However, several reasons can lead to conflicting evidence regarding the chronotype effect on performance studies. Thus, more research is needed regarding the chronotype effect on athletes’ performance and the impact of time of day on muscle strength.

Sleep and chronotype influence aerobic performance in young soccer players

People can be classified into three chronotypes (CT): morning-type (M-type), Neither-type (N-type) and Evening-type (E-type). M-types perform better in the morning, E-types in the evening. It seems that bad sleep worsens physical performance. The impact of sleep and CT on specific sports and populations is unclear. Therefore, we wanted to assess agility, strength and endurance in young soccer players in relation to their sleep and chronotype. 58 players (13-19 years) were recruited. Sleep and CT were assessed by questionnaires. The physical trial was performed at 8:30 a.m. and 6:00 p.m., and included three tests to determine agility, strength and endurance. The sample was classified by CT as M-types (n = 11), N-types (n = 29) and E-types (n = 18). Furthermore, they were categorized as people with Good Sleep/Wake quality (GSW, n = 28) and people with Bad Sleep/Wake quality (BSW, n = 30). Comparing the three CTs in the aerobic test, M-types performed better in the morning (p = 0.01), while E-types in the evening (p < 0.001). GSW performed better than BSW (p = 0.019) in the aerobic test in the p.m. session. These results underline the difference in aerobic power between M-and E-types during the morning and evening session; moreover, they show a difference in p.m. aerobic performance according to sleep quality.

Impact of time-of-day and chronotype on neuromuscular performance in semi-professional female volleyball players

This study aimed to determine if time-of-day could influence physical volleyball performance in females and to explore the relationship between chronotype and volleyball-specific performance. Fifteen young female athletes participated in a randomized counterbalanced trial, performing a neuromuscular test battery in the morning (9:00 h) and the evening (19:00 h) that consisted of volleyball standing spike, straight leg raise, dynamic balance, vertical jump, modified agility T-test and isometric handgrip tests. Chronotype was determined by the morningness-eveningness questionnaire. Compared to the morning, an increased performance was found in the standing spike (4.5%, p = .002, ES = 0.59), straight leg raise test (dominant-limb) (6.5%, p = .012, ES = 0.40), dynamic balance (non-dominant-limb) (5.0%, p = .010, ES = 0.57) and modified T-test (2.1%, p = .049, ES = 0.45) performance in the evening; while no statistical differences were reported in vertical jump tests or isometric handgrip strength. Moreover, no associations were found between chronotype and neuromuscular performance (r = -0.368-0.435, p = .052-0.439). Time-of-day affected spike ball velocity, flexibility in the dominant-limb, dynamic balance in the non-dominant-limb and agility tests. However, no association was reported among these improvements and the chronotype. Therefore, although the chronotype may not play critical role in volleyball-specific performance, evening training/matches schedules could benefit performance in semi-professional female volleyball players.

The Impact of Chronotype on the Sleep and Training Responses of Elite Female Australian Footballers

The primary aims of the present study were to examine the impact of chronotype on sleep/wake behaviour, perceived exertion, and training load among professional footballers. Thirty-six elite female professional football player's (mean ± SD: age, 25 ± 4 y; weight, 68 ± 7 kg) sleep and training behaviours were examined for 10 consecutive nights during a pre-season period using a self-report online player-management system and wrist activity monitors. All athletes completed the Morningness-Eveningness Questionnaire (rMEQ) on the first day of data collection. Eleven participants were morning types, seventeen participants were intermediate types, and three participants were evening types. Separate linear mixed models were conducted to assess differences in sleep, perceived exertion, and training behaviours between chronotype groups. Morning types woke up earlier (wake time: 07:19 ± 01:16 vs. 07:53 ± 01:01, p = 0.04) and reported higher ratings of perceived exertion compared to intermediate types (6.7 ± 1.1 vs. 5.9 ± 1.2, p = 0.01). No differences were observed between chronotype groups for bedtime, time in bed, total sleep time, sleep efficiency, training duration, or training load. In circumstances where professional female football players are required to train at a time opposing their natural circadian preference (e.g., morning type training in the evening), their perceived exertion during training may be higher than that of players that are training at a time that aligns with their natural circadian preference (e.g., evening type training in the evening). It is important for practitioners to monitor individual trends in training variables (e.g., rating of perceived exertion, training load) with relation to athlete chronotype and training time. Future research should examine the relationship between chronotype, training time, and rating of perceived exertion across different training durations.

Effects of Time-of-Day Training Preference on Resistance-Exercise Performance

Purpose: The purpose of this study was to investigate how time-of-day training preference influences resistance-exercise performance. Methods: Resistance trained males (n = 12) were recruited for this study. In a crossover, counterbalanced design, participants completed two separate bench-press exercise trials at different times of day: (a) morning (AM; 8:00 hr) and (b) evening (PM; 16:00 hr). Participants answered a questionnaire on time-of-day training preference and completed a preferred (PREF) and nonpreferred (NON-PREF) time-of-day trial. For each trial, motivation was measured using a visual analog scale prior to exercise. Participants completed 2 sets × 2 repetitions at 75% 1-RM with maximum explosiveness separated by 5 min of rest. Mean barbell velocity was measured using a linear position transducer. Participants then completed 1 set × repetitions to failure (RTF) at 75% 1-RM. Rate of perceived exertion (RPE) was measured immediately following exercise. Results: Regardless of preference, velocity (p = .025; effect size (ES) = 0.43) was higher during the PM versus AM trial. However, there were no significant differences in velocity (p = .368; ES = 0.37) between PREF and NON-PREF time of day. There were no significant differences for repetitions between PREF and NON-PREF times (p = .902; ES = 0.03). Motivation was higher in the PREF time versus NON-PREF (p = .015; ES = 0.68). Furthermore, RPE was significantly lower during the PREF time of day (p = .048; 0.55). Conclusions: Despite higher barbell velocity collectively at PM times, time-of-training preference did not largely influence resistance-exercise performance, while motivation is higher and RPE is lower during preferred times.

The effects of evening high-intensity exercise on sleep in healthy adults: A systematic review and meta-analysis

Moderate-intensity exercise is generally recommended for improving sleep, whereas, high-intensity exercise (HIE) prior to bedtime is often discouraged. We conducted a systematic review and meta-analysis to determine if acute or regular (chronic) HIE performed before bedtime disrupts nighttime sleep of healthy adult, good sleepers compared with a no-exercise control. Six databases (PubMed, EMBASE, Scopus, Web of Science, CENTRAL, and PsycINFO) were searched from inception to 31st May, 2021. Studies were experimental trials published in English language, objectively (polysomnography, actigraphy) and/or subjectively assessed sleep after evening HIE in sedentary and physically fit, good sleepers (aged 18-50 y old). The revised Cochrane risk of bias tool for randomized trials was used to assess risk of bias in the included studies. The random-effects model was used for the meta-analyses. We included 15 acute evening HIE studies in the meta-analysis with a total of 194 participants. Acute evening HIE ending 0.5-4 h before bedtime decreased rapid eye movement sleep (-2.34%; p = 0.002) compared with a no-exercise control. No other significant sleep changes occurred. A regular evening HIE did not disrupt nighttime sleep. Overall, acute evening HIE performed 2-4 h before bedtime does not disrupt nighttime sleep of healthy, young and middle-aged adults. PROSPERO, protocol registration number: CRD42020218299.

Influence of circadian rhythms on sports performance

Chronobiology is the scientific discipline of study of biological rhythms, a term that has gained ground in the sports world. Recently numerous studies have indicated that the time of day in which sports are practiced influences the achievement of good physical performance. The aim of this review was to study the relationship between circadian rhythms and physical performance, according to the latest published data. In addition, the physiological processes involved in the physical response and the differences according to the type of sport and athletes' characteristics were studied. A bibliographic search was carried out through five databases (Pubmed, Scopus, Researcher Gate, Google Scholar, UOC Library), focusing on articles published in the last ten years and written in English and Spanish. 36 papers met the inclusion criteria. Body temperature is a factor that shows a circadian pattern with a marked peak in the later afternoon, time of the day at which physical performance is at its highest, i.e. speed, agility, distance covered, jumping power. The perception of effort is also higher in the afternoon. Regarding the chronotype, evening types seem to be the most affected to do sports out of their optimal time-of-day. The tendency shows more morning types as age increases. Training sessions should be planned according to the optimal time of day for each athlete. It's essential to take into account individual chronotype. The desynchronization of circadian rhythms can cause a decrease in physical performance.

Sleep Characteristics and Mood of Professional Esports Athletes: A Multi-National Study

Esports is becoming increasingly professionalized, yet research on performance management is remarkably lacking. The present study aimed to investigate the sleep and mood of professional esports athletes. Participants were 17 professional esports athletes from South Korea (N = 8), Australia (N = 4), and the United States (N = 5) who played first person shooter games (mean age 20 ± 3.5 years, 100% male). All participants wore a wrist-activity monitor for 7–14 days and completed subjective sleep and mood questionnaires. Participants had a median total sleep time of 6.8 h and a sleep efficiency of 86.4% per night. All participants had significantly delayed sleep patterns (median sleep onset 3:43 a.m. and wake time 11:24 a.m.). Participants had a median sleep onset latency of 20.4 min and prolonged wake after sleep onset of 47.9 min. Korean players had significantly higher depression scores compared to the other groups (p < 0.01) and trained longer per day than the Australian or United States teams (13.4 vs. 4.8 vs. 6.1 h, respectively). Depression scores were strongly correlated with number of awakenings, wake after sleep onset, and daily training time (p < 0.05). As the first pilot sleep study in the esports field, this study indicates that esports athletes show delayed sleep patterns and have prolonged wake after sleep onset. These sleep patterns may be associated with mood (depression) and training time. Sleep interventions designed specifically for esports athletes appear warranted.

Chronobiological Effects on Mountain Biking Performance

BACKGROUND

the aim of this study was to analyze the chronobiology influence on the mechanical, kinematic, and physiological variables in a mountain bike (MTB) time trial.

METHODS

16 mountain bike (MTB) male athletes volunteered to participate. Their characteristics were as follows: body mass 70.2 ± 5.4 kg, stature 172.7 ± 4.0 cm, body fat 9.8 ± 3.5%, and VO_2max 52.3 ± 3.9 mL/kg/min. Two 20 min MTB maximal protocols were applied, the first one in the morning and a second one in the afternoon period.

RESULTS

No differences were found for all the variables studied, except for the pedaling cadence (stroke rate), which showed higher values during the morning protocol (85.06 ± 7.58 vs. 82.63 ± 7.41 rpm; p = 0.044). Significant correlations between morning and afternoon physiological and mechanical variables were observed: heart rate (r = 0.871); external mechanical power-maximum (r = 0.845), mean (r = 0.938), and relative (r = 0.933), as well as in the cadence-stroke rate (r = 0.825).

CONCLUSIONS

our results reveal a similar impact and significant relationship between morning and afternoon impact concerning the majority of the physiological and mechanical variables, which indicates that the period of the day does not influence the external and internal impact associated with the MTB time trial maximal protocol.

Effect of chronotype on motor skills specific to soccer in adolescent players

Circadian rhythms influence daily behavior, psychological and physiological functions, as well as physical performance. Three chronotypes are distinguished according to the preferences people typically display for activity at certain times of day: Morning, Neither, and Evening types (M-, N- and E-types). The chronotype changes with age: eveningness tends to be stronger in youth and morningness in older age. The progressive shift toward eveningness during adolescence creates misalignment with morning society schedules and can lead to a deterioration in intellectual and physical performance. Soccer is one of the world's most popular sports practiced by adolescents and soccer workouts are usually held after school in the afternoon or evening. Performance in soccer is related to a host of factors, including physiological variables and motor skills that have a circadian variation. The aim of this study was to determine the effect of chronotype on motor skills specific to soccer, specifically whether agility, aerobic endurance, and explosive power differ among the three chronotypes in relation to the time of day. For this study 141 adolescent soccer players filled in the Morningness-Eveningness Questionnaire (MEQ) for the assessment of chronotype. A subsample of 75 subjects, subdivided in M-types (n= 25), E-types (n= 25), and N-types (n= 25), performed three tests (Sargent Jump Test - SJT, Illinois Agility Test - IAT, and 6-Minutes Run Test - 6MRT) at a morning and an evening training session (9:00 am and 6:00 pm). Mixed ANOVA was used to test the interactions between chronotypes, physical performance, and time. On all tests, better performance during the morning than the evening session was observed for the M-types (p< .05), whereas the E-types performed better in the evening than in the morning session (p< .05), and no differences in test performance were detected for the N-types. These findings underline the importance of a correct chronobiological approach to sports training. Scheduling training sessions according to an athlete's circadian preferences could be a valid strategy to enhance performance.

Circadian mismatch and cardiovascular response to a performance challenge: Larks in morning and evening work sessions

We presented morning chronotype ("Lark") university undergraduate volunteers a more or less difficult Sternberg-type recognition memory task either in the morning (8-11 am) or in the evening (5-8 pm) with instructions that they could win a prize if they were 85% successful. We established morning chronotype using the Composite Scale for Morningness (Smith et al., 1989), employing a tertile split on a pool of scale scores that ranged from 13 (extreme eveningness) to 55 (extreme morningness). Participants had scores above 37, with most participants identifying as White/Caucasian, Hispanic/Latino, or Black/African-American. Among women (final sample n = 81), systolic blood pressure and mean arterial pressure responses assessed during work formed a crossover pattern, being positively correspondent to difficulty in the morning but negatively correspondent to difficulty in the evening. Heart rate and heart pre-ejection period responses ran parallel in the morning but not the evening. Among men (final sample n = 41), cardiovascular responses differed neither with difficulty nor with time. Findings for women support the extension of a recent analysis of fatigue influence on effort and associated cardiovascular responses to the phenomenon of circadian mismatch. Findings for men do not support the extension but should be interpreted guardedly in light of prohibitively low cell ns and unexpected findings on key subjective measures.

Clocking In, Working Out: Circadian Regulation of Exercise Physiology

Research over the past century indicates that the daily timing of physical activity impacts on both immediate performance and long-term training efficacy. Recently, several molecular connections between circadian clocks and exercise physiology have been identified. Circadian clocks are protein-based oscillators that enable anticipation of daily environmental cycles. Cell-autonomous clocks are present in almost all cells of the body, and their timing is set by a variety of internal and external signals, including hormones and dietary intake. Improved understanding of the relationship between molecular clocks and exercise will benefit professional athletes and public health guidelines for the general population. We discuss here the role of circadian clocks in exercise, and explore time-of-day effects and the proposed molecular and physiological mechanisms.

Chronotype, Physical Activity, and Sport Performance: A Systematic Review

BACKGROUND

Many variables related to sport have been shown to have circadian rhythms. Chronotype is the expression of circadian rhythmicity in an individual, and three categories of chronotype are defined: morning types (M-types), evening types (E-types), and neither types (N-types). M-types show earlier peaks of several psychophysiological variables during the day than E-types. The effect of chronotype on athletic performance has not been extensively investigated.

OBJECTIVE

The objective of the present review was to study the effect of chronotype on athletic performance and the psychophysiological responses to physical activity.

METHODS

The present review adheres to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) reporting guidelines. We searched PubMed, Scopus, and Web of Science for scientific papers using the keywords "chronotype", "circadian typology", "morningness", and "eveningness" in combination with each of the words "sport", "performance", and "athletic." Relevant reference lists were inspected. We limited the search results to peer-reviewed papers published in English from 1985 to 2015.

RESULTS

Ten papers met our inclusion criteria. Rating of perceived exertion and fatigue scores in relation to athletic performances are influenced by chronotype: M-types perceived less effort when performing a submaximal physical task in the morning than did N- and E-types. In addition, M-types generally showed better athletic performances, as measured by race times, in the morning than did N- and E-types. Other results concerning chronotype effect on physiological responses to physical activity were not always consistent: heterogeneous samples and different kinds of physical activity could partially explain these discrepancies.

CONCLUSIONS

Sports trainers and coaches should take into account the influence of both the time of day and chronotype effect when scheduling training sessions into specific time periods.

Circadian Effects on Performance and Effort in Collegiate Swimmers

Although individual athletic performance generally tends to peak in the evening, individuals who exhibit a strong diurnal preference perform better closer to their circadian peak. Time-of-day performance effects are influenced by circadian phenotype (diurnal preference and chronotype-sleep-wake patterns), homeostatic energy reserves and, potentially, genotype, yet little is known about how these factors influence physiological effort. Here, we investigate the effects of time of day, diurnal preference, chronotype, and PER3 (a circadian clock gene) genotype on both effort and performance in a population of Division I collegiate swimmers (n = 27). Participants competed in 200m time trials at 7:00 and 19:00 and were sampled pre- and post-trial for salivary α-amylase levels (as a measure of physiological effort), allowing for per-individual measures of performance and physiological effort. Hair samples were collected for genotype analysis (a variable-number tandem-repeat (VNTR) and a single nucleotide polymorphism (SNP) in PER3). Our results indicate significant and parallel time-of-day by circadian phenotype effects on swim performance and effort; evening-type swimmers swam on average 6% slower with 50% greater α-amylase levels in the morning than they did in the evening, and morning types required 5-7 times more effort in the evening trial to achieve the same performance result as the morning trial. In addition, our results suggest that these performance effects may be influenced by gene (circadian clock gene PER3 variants) by environment (time of day) interactions. Participants homozygous for the PER3^4,4 length variant (rs57875989) or who possess a single G-allele at PER3 SNP rs228697 swam 3-6% slower in the morning. Overall, these results suggest that intra-individual variation in athletic performance and effort with time of day is associated with circadian phenotype and PER3 genotype.

Development and initial validation of the Morningness-Eveningness Exercise Preference Questionnaire (MEEPQ) in Japanese university students

The aim of this study was to develop a questionnaire to conveniently assess the diurnal preferences of physical activity (PA) in Japanese university students. A total of 219 subjects completed our novel Morningness-eveningness Exercise Preference Questionnaire (MEEPQ). The MEEPQ consisted of 30 items (15 items for the morning and the same 15 items for the evening) rated on a 5-point Likert scale concerning their preference for participating in PA in the morning and evening. The morning score (MS) and evening score (ES) were determined by summing each of the respective 15 items. The internal consistency and construct validity were assessed, and a factor analysis was conducted. To examine the external validity of the MEEPQ, participants wore an accelerometer for seven consecutive days to measure their PA levels objectively. Finally, the test-retest reliability was evaluated at a one-month interval. The MEEPQ showed excellent internal consistency (Cronbach's alpha = 0.896) and construct validity (morning KMO = 0.913, evening KMO = 0.875). A factor analysis showed a three-factor structure involving Physical Wellness (MEEPQ-W), Psychological Well-Being (MEEPQ-P) and Exercise Barrier (MEEPQ-B). The percent of variance was largest for MEEPQ-W in the morning (45.2%) and MEEPQ-P in the evening (40.8%). Test-retest showed that MEEPQ scores had fair repeatability. Significant and positive associations between scores and objectively measured PA levels were found in the MS and 6-9 AM PA and in the ES and 6-9 PM and 9 PM- 0 AM PA (all p<0.05). In summary, the novel MEEPQ showed relatively good agreement and thus can be used for Japanese university student samples. In the MEEPQ, three factors (the physical wellness, psychological well-being and exercise barrier) contributed to a morning or evening PA preference. The summed scores were significantly associated with the objectively measured PA levels in both the morning and evening. Therefore the MEEPQ appears to be a suitable tool for assessing diurnal PA preferences.

Ratings of Perceived Exertion and Self-reported Mood State in Response to High Intensity Interval Training. A Crossover Study on the Effect of Chronotype

The aim of this study was to investigate the influence of chronotype on mood state and ratings of perceived exertion (RPE) before and in response to acute high intensity interval exercise (HIIE) performed at different times of the day. Based on the morningness–eveningness questionnaire, 12 morning-types (M-types; N = 12; age 21 ± 2 years; height 179 ± 5 cm; body mass 74 ± 12 kg) and 11 evening-types (E-types; N = 11; age 21 ± 2 years; height 181 ± 11 cm; body mass 76 ± 11 kg) were enrolled in a randomized crossover study. All subjects underwent measurements of Profile of Mood States (POMS), before (PRE), after 12 (POST12) and 24 h (POST24) the completion of both morning (08.00 am) and evening (08.00 p.m.) training. Additionally, Global Mood Disturbance and Energy Index (EI) were calculated. RPE was obtained PRE and 30 min POST HIIE. Two-way ANOVA with Tukey’s multiple comparisons test of POMS parameters during morning training showed significant differences in fatigue, vigor and EI at PRE and POST24 between M-types and E-types. In addition, significant chronotype differences were found only in POST12 after the evening HIIE for fatigue, vigor and EI. For what concerns Borg perceived exertion, comparing morning versus evening values in PRE condition, a higher RPE was observed in relation to evening training for M-types (P = 0.0107) while E-types showed higher RPE values in the morning (P = 0.008). Finally, intragroup differences showed that E-types had a higher RPE respect to M-types before (P = 0.002) and after 30 min (P = 0.042) the morning session of HIIE. No significant changes during the evening training session were found. In conclusion, chronotype seems to significantly influence fatigue values, perceived exertions and vigor in relation to HIIE performed at different times of the day. Specifically, E-types will meet more of a burden when undertaking a physical task early in the day. Practical results suggest that performing a HIIE at those times of day that do not correspond to subjects’ circadian preference can lead to increased mood disturbances and perceived exertion. Therefore, an athlete’s chronotype should be taken into account when scheduling HIIE.

Trial registration:

ACTRN12617000432314, registered 24 March 2017, “retrospectively registered”.

Web address of trial:

https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=371862&showOriginal=true&isReview=true

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.

The Effect of Chronotype on Psychophysiological Responses during Aerobic Self-Paced Exercises

It was hypothesized that an individual's chronotype might influence the response to physical activity at a given time of day. This study aimed to analyze the psychophysiological responses during a walking task at different times of day in individuals with different chronotypes. 46 students ( M age = 24.8yr., SD = 7.2) filled in the Morningness-Eveningness Questionnaire to determine chronotypes. Heart rate, walking time, and the rating of perceived exertion (RPE) were measured during two self-paced walking sessions: one in the morning (08:30) and one in the afternoon (15:30). A multivariate analysis of variance found a significant interaction between chronotype and time of day. The post hoc analysis showed a significant difference for RPE in the morning session, with evening types reporing a higher RPE compared with the morning types. The chronotype and the time of day when a physical task is undertaken can influence the RPE response, although it might not influence physiological or performance parameters. This has to be taken into account, because it can affect test reliability as well as possibly have a negative influence on the affective responses to a given task.

Factors to consider when assessing diurnal variation in sports performance: the influence of chronotype and habitual training time-of-day

PURPOSE

The aim of this study was to compare morning and evening time-trial performance, RPE and mood state of trained swimmers, taking into account chronotype, habitual training time-of-day and PERIOD3 (PER3) variable number tandem repeat genotype.

METHODS

Twenty-six swimmers (18 males, age: 32.6 ± 5.7 years) swam 200 m time trials (TT) at 06h30 and 18h30 in a randomised order.

RESULTS

There was no difference between morning and evening performance when the swimmers were considered as a single group (06h30: 158.8 ± 22.7 s, 18h30: 158.5 ± 22.0 s, p = 0.611). However, grouping swimmers by chronotype and habitual training time-of-day allowed us to detect significant diurnal variation in performance, such that morning-type swimmers and those who habitually train in the morning were faster in the 06h30 TT (p = 0.036 and p = 0.011, respectively). This was accompanied by lower ratings of perceived exertion (RPE) scores post-warm-up, higher vigour and lower fatigues scores prior to the 06h30 TT in morning-type swimmers or those who trained in the morning. Similarly, neither types and those who trained in the evenings had lower fatigue and higher vigour prior to the 18h30 TT.

CONCLUSIONS

It appears that both chronotype and habitual training time-of-day need to be considered when assessing diurnal variation in performance. From a practical point of view, athletes and coaches should be aware of the potentially powerful effect of training time on shifting time-of-day variation in performance.