Consistent Morning Exercise May Be Beneficial for Individuals With Obesity

Tailoring Exercise Prescription for Effective Diabetes Glucose Management

CONTEXT

Physical activity, exercise, or both are a staple of lifestyle management approaches both for type 1 diabetes mellitus (T1DM) and type 2 diabetes (T2DM). While the current literature supports both physical activity and exercise for improving glycemic control, reducing cardiovascular risk, maintaining proper weight, and enhancing overall well-being, the optimal prescription regimen remains debated.

EVIDENCE ACQUISITION

We searched PubMed and Google Scholar databases for relevant studies on exercise, insulin sensitivity, and glycemic control in people with T1DM and T2DM.

EVIDENCE SYNTHESIS

In patients with T1DM, exercise generally improves cardiovascular fitness, muscle strength, and glucose levels. However, limited work has evaluated the effect of aerobic plus resistance exercise compared to either exercise type alone on glycemic outcomes. Moreover, less research has evaluated breaks in sedentary behavior with physical activity. When considering the factors that may cause hypoglycemic effects during exercise in T1DM, we found that insulin therapy, meal timing, and neuroendocrine regulation of glucose homeostasis are all important. In T2DM, physical activity is a recommended therapy independent of weight loss. Contemporary consideration of timing of exercise relative to meals and time of day, potential medication interactions, and breaks in sedentary behavior have gained recognition as potentially novel approaches that enhance glucose management.

CONCLUSION

Physical activity or exercise is, overall, an effective treatment for glycemia in people with diabetes independent of weight loss. However, additional research surrounding exercise is needed to maximize the health benefit, particularly in "free-living" settings.

Longitudinal timing of physical activity and associated cardiometabolic and behavioral health outcomes in young adults

BACKGROUND

This is the first study to examine longitudinal associations between self-selected timing of moderate-to-vigorous physical activity (MVPA) and health outcomes in young adults over 18 months.

METHODS

Young adults (N = 434, Mage = 23.9, SDage = 4.6 years) enrolled in a weight management trial recorded 4-7 days of ActiGraph wear time at ≥1 time point (baseline, months 6, 12, and 18). Time-of-day categories were based on quartiles of the temporal distribution of MVPA min/h at baseline: morning (06:00-11:59), afternoon (12:00-15:59), evening (16:00-18:59), and night (19:00-00:59). The proportion of weekly MVPA accumulated during each time category was the predictor in longitudinal linear mixed-effects models predicting body mass index (BMI) and total weekly MVPA. Longitudinal quasibinomial generalized estimating equations models predicted cardiometabolic risk. Interactions were tested, and marginal trend estimates were generated for sex and age subgroups.

RESULTS

The analytic sample was 79% female and 49% non-Hispanic White, with a mean (±SD) weekly MVPA of 311 ± 167 min at baseline. In adjusted models, there were no associations with BMI. Morning MVPA was inversely associated with cardiometabolic risk (OR [95% CI]: 0.99 [0.98-0.99]) for both sex and age groups. Evening MVPA was inversely associated with cardiometabolic risk for 26-35 year olds (0.98 [0.97-0.99]). Morning MVPA was associated with greater total MVPA across subgroups, and afternoon MVPA was associated with less total MVPA in women.

CONCLUSIONS

Over 18 months, incremental health benefits may accrue with optimal activity timing in young adults. Activity-based interventions designed to improve cardiometabolic and behavioral health outcomes in young adults may be optimized by tailoring timing recommendations to demographic factors.

The impact of exercise timing on energy intake: A systematic review and meta-analysis of diurnal and meal timing effects

This systematic review and meta-analysis examine the literature (up to August 2nd, 2024) on the influence of exercise timing on energy intake in both children and adults. A comprehensive search was conducted using MEDLINE, EMBASE, Cochrane Library, SPORTDiscus, and Web of Science Core Collection, following PRISMA guidelines. The review was registered in Prospero (CRD42024553381) and evaluated using QUADAS-2. From an initial 3276 articles, a meta-analysis (six studies) revealed that daily energy intake was not significantly lower when exercise was performed in the morning versus the afternoon/evening: mean difference of 64 ± 77 kcal (95% CI: 86 to 215 kcal; p = 0.403). A meta-analysis (three studies, all with children) comparing lunch energy intake before versus after exercise showed a significant difference in energy intake when exercise was performed post-meal: (-39 ± 13 kcal, 95% CI: 63 to -14 kcal; p = 0.002). For the meta-analysis of delayed lunch (five studies), where exercise ended 15 min to 4 h before the meal, and the delay between the start of each exercise condition within the same study was typically around 2 h, no significant difference in energy intake was found (-2±67 kcal; 95% CI: 134 to 130 kcal; p = 0.977). Regarding chronic exercise, a decrease in energy intake was observed with evening exercise (one study), morning exercise (two studies) or independently of exercise timing (two studies). In conclusion, findings suggest acute exercise may reduce intake in children and adolescents, but this effect is dependent on the timing of exercise.

Efficacy of morning versus afternoon aerobic exercise training on reducing metabolic syndrome components: A randomized controlled trial

A supervised intense aerobic exercise program improves the health of individuals with metabolic syndrome (MetS). However, it is unclear whether the timing of training within the 24 h day would influence those health benefits. The present study aimed to determine the influence of morning vs. afternoon exercise on body composition, cardiometabolic health and components of MetS. One hundred thirty-nine individuals with MetS were block randomized into morning (AMEX; n = 42) or afternoon (PMEX; n = 59) exercise training groups, or a non-training control group (Control; n = 38). Exercise training was comprised of 48 supervised high-intensity interval sessions distributed over 16 weeks. Body composition, cardiorespiratory fitness (assessed byV ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ ), maximal fat oxidation (FOmax), blood pressure and blood metabolites were assessed before and after the intervention. Compared with the non-training Control, both exercise groups improved similarly body composition (-0.7% fat loss; P = 0.002), waist circumference (-2.1 cm; P < 0.001), diastolic blood pressure (-3.8 mmHg; P = 0.004) andV ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ (3.5 mL kg-1  min-1; P < 0.001) with no differences between training groups. AMEX, in comparison with PMEX, reduced systolic blood pressure (-4% vs. -1%; P = 0.019), plasma fasting insulin concentration (-12% vs. -5%; P = 0.001) and insulin resistance (-14% vs. -4%; P = 0.006). Furthermore, MetS Z score was further reduced in the AMEX compared to PMEX (-52% vs. -19%; P = 0.021) after training. In summary, high-intensity aerobic exercise training in the morning in comparison to training in the afternoon is somewhat more efficient at reducing cardiometabolic risk factors (i.e. systolic blood pressure and insulin sensitivity). KEY POINTS: The effect of exercise time of day on health promotion is an area that has gained interest in recent years; however, large-scale, randomized-control studies are scarce. People with metabolic syndrome (MetS) are at risk of developing cardiometabolic diseases and reductions in this risk with exercise training can be precisely gauged using a compound score sensitive to subtle evolution in each MetS component (i.e. Z score). Supervised aerobic exercise for 16 weeks (morning and afternoon), without dietary restriction, improved cardiorespiratory and metabolic fitness, body composition and mean arterial pressure compared to a non-exercise control group. However, training in the morning, without changes in exercise dose or intensity, reduced systolic blood pressure and insulin resistance further compared to when training in the afternoon. Thus, high-intensity aerobic exercise training in the morning is somewhat more efficient in improving the health of individuals with metabolic syndrome.

Weight loss in patients with severe obesity after bariatric surgery-the potential role of the chrono-nutrition, chronotype and the circadian misalignment: A study protocol of the ChronoWise prospective cohort

BACKGROUND

Despite the potential effectiveness of bariatric surgery in promoting weight loss, a considerable proportion of patients still face the challenge of achieving optimal post-surgery outcomes. The timing of eating, in addition to the content of what is eaten, as well as chronotype and social jetlag (a marker of circadian misalignment), have been implicated in weight regulation. However, the current understanding of these chrono-related behaviours in individuals undergoing bariatric surgery is still scarce. Thus, this study aims to evaluate the role of chrono-nutrition, chronotype, and circadian misalignment in the weight-loss trajectory among individuals living with severe obesity who underwent bariatric surgery.

METHODS

The ChronoWise project is a prospective single-centre cohort study designed to follow patients experiencing bariatric surgery at the Santo António Local Health Unit (ULSSA), Porto, Portugal. Participants will be recruited and evaluated at pre-surgery and followed-up over 3 and 6 months after surgery. The baseline evaluation will be conducted face-to-face during the hospital stay and by telephone or video call on the subsequent evaluations, following standard procedures. Data collection includes sociodemographics, food intake, chrono-nutrition behaviours, sleep time behaviour, sleep quality, screen time, physical activity and exercise behaviours, anthropometric measurements, and biochemical parameters. The 'Munich Chronotype Questionnaire' will be used to assess chronotype and social jet lag. Chrono-nutrition dimensions will be measured by the 'Chrononutrition Profile-Questionnaire' in all evaluations. Weight and height will be self-reported and retrieved from medical registries. trajectories of weight-loss will be obtained.

DISCUSSION

This study will add important evidence on the role of chrono-nutrition, chronotype and social jetlag profile in weight-loss outcomes after bariatric surgery. Identifying novel approaches to change the paradigm of post-surgical weight management towards a tailored treatment aligned with circadian rhythm may be useful to strengthen the existing treatments and improve patients' response to bariatric surgery.

Confirming the Causal Role of Consistent Contexts in Developing a Walking Habit: A Randomized Comparison With Varied Contexts

BACKGROUND

Physical activity interventions using habit development may help people increase and then maintain physical activity increases over time. Enacting behavior in consistent contexts is a central component of habit development, yet its causal role in habit development in health behaviors has not been confirmed.

PURPOSE

This study tests the causal role of consistent context in habit development in health behavior, using a randomized control trial of a planning intervention to develop a walking habit in 127 insufficiently active, working, midlife adults in a real-world setting.

METHODS

We compare participants who plan walking in consistent contexts with controls who plan walking in varied contexts and with controls not required to plan on a change in average daily steps (measured using an accelerometer) and inhabit automaticity during a 4-week intervention and at a 4-week follow-up.

RESULTS

As expected, consistent and varied context planners increased walking during the intervention, but only consistent context planners developed (and maintained) habit automaticity. Counter to expectations, consistent context planners did not show walking maintenance. However, across conditions, participants who developed more habit automaticity during the intervention also maintained walking more (decreased less). Having a routine daily schedule moderated some effects. Notably, no-plan controls with greater routine developed more habit automaticity, mediated by walking in more consistent contexts.

CONCLUSIONS

This study confirms the causal role of consistent contexts in developing a walking habit, in a real-world setting, with an important but challenging population for physical activity interventions and identifies a facilitating condition common for many: a routine schedule.

Time of exercise differentially impacts bone growth in mice

Although physical training has been shown to improve bone mass, the time of day to exercise for optimal bone growth remains uncertain. Here we show that engaging in physical activity during the early active phase, as opposed to the subsequent active or rest phase, results in a more substantial increase in bone length of male and female mice. Transcriptomic and metabolomic methodologies identify that exercise during the early active phase significantly upregulates genes associated with bone development and metabolism. Notably, oxidative phosphorylation-related genes show a rhythmic expression in the chondrification centre, with a peak at the early active phase, when more rhythmic genes in bone metabolism are expressed and bone growth is synergistically promoted by affecting oxidative phosphorylation, which is confirmed by subsequent pharmacological investigations. Finally, we construct a signalling network to predict the impact of exercise on bone growth. Collectively, our research sheds light on the intricacies of human exercise physiology, offering valuable implications for interventions.

Physical activity and exercise for weight loss and maintenance in people living with obesity

Physical activity and exercise training programs are integral part of a comprehensive obesity management approach. In persons with overweight or obesity, exercise training, specifically aerobic (i.e. endurance) training, is associated with significant additional weight loss compared to the absence of training. However the magnitude of effect remains modest amounting to only 2-3 kg additional weight loss on average. Comparable effects have been observed for total fat loss. Exercise training, specifically aerobic training, is also associated with decreased abdominal visceral fat as assessed by imaging techniques, which is likely to benefit cardiometabolic health in persons with obesity. Based on data from controlled trials with randomization after prior weight loss, the evidence for weight maintenance with exercise training is as yet not conclusive, although retrospective analyses point to the value of relatively high-volume exercise in this regard. Resistance (i.e. muscle-strengthening) training is specifically advised for lean mass preservation during weight loss. Given the relatively limited effect of exercise training on weight loss as such, the changes in physical fitness brought about by exercise training cannot be overlooked as they provide major health benefits to persons with obesity. Aerobic, as well as combined aerobic and resistance training, increase cardiorespiratory fitness (VO2max) while resistance training, but not aerobic training, improves muscle strength even in the absence of a significant change in muscle mass. Regarding the overall management strategy, adherence in the long term to new lifestyle habits remains a challenging issue to be addressed by further research.

The diurnal pattern of moderate-to-vigorous physical activity and obesity: a cross-sectional analysis

OBJECTIVE

Moderate-to-vigorous physical activity (MVPA) is obesity-protective. However, the optimal time of the day to engage in MVPA for weight management is controversial. This study is designed to investigate the influence of the diurnal pattern of MVPA on the association between MVPA and obesity.

METHODS

A total of 5285 participants in the 2003 to 2006 National Health and Nutrition Examination Survey (NHANES) were cross-sectionally analyzed. The diurnal pattern of objectively measured MVPA was classified into three clusters by K-means clustering analysis: morning (n = 642); midday (n = 2456); and evening (n = 2187). The associations of MVPA level and the diurnal pattern with obesity were tested.

RESULTS

A strong linear association between MVPA and obesity was found in the morning group, whereas a weaker curvilinear association between MVPA and obesity was observed in the midday and evening groups, respectively. Among those who met the physical activity guidelines, the adjusted means for BMI were 25.9 (95% CI: 25.2-26.6), 27.6 (95% CI: 27.1-28.1), and 27.2 (95% CI: 26.8-27.7) kg/m2 in the morning, midday, and evening groups, respectively, and for waist circumference were 91.5 (95% CI: 89.4-93.6), 95.8 (95% CI: 94.7-96.9), and 95.0 (95% CI: 93.9-96.1) cm, respectively.

CONCLUSIONS

The diurnal pattern of MVPA influences the association between MVPA and obesity. The promising role of morning MVPA for weight management warrants further investigation.

A study on the relationships between playfulness, physical self-efficacy, and school happiness among middle school students participating in "0th-period physical education class" in South Korea

The purpose of this study is to create a scientific basis for the establishment of "0th-period physical education class" activities in schools in the future, with the expectation that the associations of morning exercise can be activated in the Korean educational community. To achieve this goal, the present study aimed to determine the relationship between the playfulness experienced during the early morning exercise of middle school students and their physical self-efficacy and education for happiness. To examine the model, questionnaires were collected from 296 middle school students located in Seoul and Gyeonggi-do, South Korea. Correlation analysis and standard multiple regression analysis were performed to analyze the data using the SPSS 21.0. The findings were as follows: First, the playfulness of the middle school "0th-period physical education class" had a significant effect on physical self-efficacy. Second, playfulness had a significant effect on education for happiness. Thirdly, physical self-efficacy was found to have a significant effect on education for happiness. Based on the results of this study, we suggest that a "0th-period physical education class" with various activities should be held during the legally required time in South Korea.

The importance of exercise for glycemic control in type 2 diabetes

Exercise is a first-line therapy recommended for patients with type 2 diabetes (T2D). Although moderate to vigorous exercise (e.g. 150 min/wk) is often advised alongside diet and/or behavior modification, exercise is an independent treatment that can prevent, delay or reverse T2D. Habitual exercise, consisting of aerobic, resistance or their combination, fosters improved short- and long-term glycemic control. Recent work also shows high-intensity interval training is successful at lowering blood glucose, as is breaking up sedentary behavior with short-bouts of light to vigorous movement (e.g. up to 3min). Interestingly, performing afternoon compared with morning as well as post-meal versus pre-meal exercise may yield slightly better glycemic benefit. Despite these efficacious benefits of exercise for T2D care, optimal exercise recommendations remain unclear when considering, dietary, medication, and/or other behaviors.

Best Time of Day for Strength and Endurance Training to Improve Health and Performance? A Systematic Review with Meta-analysis

BACKGROUND

Current recommendations for physical exercise include information about the frequency, intensity, type, and duration of exercise. However, to date, there are no recommendations on what time of day one should exercise. The aim was to perform a systematic review with meta-analysis to investigate if the time of day of exercise training in intervention studies influences the degree of improvements in physical performance or health-related outcomes.

METHODS

The databases EMBASE, PubMed, Cochrane Library, and SPORTDiscus were searched from inception to January 2023. Eligibility criteria were that the studies conducted structured endurance and/or strength training with a minimum of two exercise sessions per week for at least 2 weeks and compared exercise training between at least two different times of the day using a randomized crossover or parallel group design.

RESULTS

From 14,125 screened articles, 26 articles were included in the systematic review of which seven were also included in the meta-analyses. Both the qualitative synthesis and the quantitative synthesis (i.e., meta-analysis) provide little evidence for or against the hypothesis that training at a specific time of day leads to more improvements in performance-related or health-related outcomes compared to other times. There was some evidence that there is a benefit when training and testing occur at the same time of day, mainly for performance-related outcomes. Overall, the risk of bias in most studies was high.

CONCLUSIONS

The current state of research provides evidence neither for nor against a specific time of the day being more beneficial, but provides evidence for larger effects when there is congruency between training and testing times. This review provides recommendations to improve the design and execution of future studies on this topic.

REGISTRATION

PROSPERO (CRD42021246468).

Is There an Optimal Time of Day for Exercise? A Commentary on When to Exercise for People Living With Type 1 or Type 2 Diabetes

Exercise is a cornerstone of diabetes self-care because of its association with many health benefits. Several studies that have explored the best time of day to exercise to inform clinical recommendations have yielded mixed results. For example, for people with prediabetes or type 2 diabetes, there may be benefits to timing exercise to occur after meals, whereas people with type 1 diabetes may benefit from performing exercise earlier in the day. One common thread is the health benefits of consistent exercise, suggesting that the issue of exercise timing may be secondary to the goal of helping people with diabetes establish an exercise routine that best fits their life.

Consistent exercise timing as a strategy to increase physical activity: A feasibility study

Introduction/Purpose

Observational research suggests that consistent exercise timing could be leveraged to promote moderate-to-vigorous physical activity (MVPA) among adults with obesity. However, the feasibility and acceptability of prescribed consistent exercise timing in a free-living setting is unknown. The purpose of this study was to assess the feasibility and acceptability of prescribed consistent exercise timing in a free-living setting among inactive adults with obesity (primary) and to compare MVPA timing prescriptions and characterize exercise barriers/facilitators (secondary).

Methods

Using a within-subjects design, inactive adults with obesity (n=15) were randomized in counterbalanced order to three 3-wk exercise timing conditions separated by 2-wk washout periods: 1) consistent morning, 2) consistent evening, and 3) choice timing (control). Feasibility was assessed using prespecified benchmarks. Acceptability and preferred timing were assessed with questionnaires post-intervention. Secondarily, exercise timing and MVPA were assessed via accelerometry and nightly surveys and barriers/facilitators were assessed with nightly surveys.

Results

All feasibility benchmarks were achieved (e.g., timing adherence = 69.9% via accelerometry and 87.4% via self-report (target: ≥60%)). Consistent exercise timing was acceptable (mean rating = 3.7 of 5 (target: ≥3.5)). Choice was the most popular prescription. There were medium- to large-sized effects (partial η2 of 0.09-0.16) of condition on MVPA; MVPA was higher during the morning and evening conditions versus choice condition. Facilitators were similar across conditions, while some barriers were time specific.

Conclusion

Prescribed exercise timing in a free-living setting appears feasible and acceptable. While choice timing was most preferred, consistent timing appeared most effective for increasing MVPA. Data warrant larger trials to test the efficacy and mechanisms of consistent exercise timing as a translational strategy for promoting MVPA. Pending findings from a fully powered randomized trial, practitioners interested in promoting MVPA among their patients or clients could consider encouraging exercise at a consistent time day-to-day.

Effects of Morning Vs. Evening exercise on appetite, energy intake, performance and metabolism, in lean males and females

Exercise is an important component of a weight management strategy. However, little is known about whether circadian variations in physiological and behavioural processes can influence the appetite and energy balance responses to exercise performed at different times of the day. This study compared the effects of morning and evening exercise on appetite, post-exercise energy intake, and voluntary performance. In randomised, counterbalanced order, 16 healthy males and females (n = 8 each) completed two trials, performing morning exercise at 10:30 (AMEx) or evening exercise at 18:30 (PMEx). Exercise consisted of 30 min steady-state cycling (60% V˙ O_2peak), and a 15-min performance test. A standardised meal (543 ± 86 kcal) was consumed 2-h before exercise and ad-libitum energy intake was assessed 15 min after exercise, with subjective appetite measured throughout. Absolute ad-libitum energy intake was 152 ± 126 kcal greater during PMEx (P < 0.001), but there was no differences in subjective appetite between trials immediately pre-exercise, or immediately before the post-exercise meal (P ≥ 0.060). Resting energy expenditure (P < 0.01) and carbohydrate oxidation (P < 0.05) were greater during AMEx, but there were no differences in substrate oxidation or energy expenditure during exercise (P ≥ 0.155). Exercise performance was not different between trials (P = 0.628). In conclusion, acute morning and evening exercise prompt similar appetite responses, but post-exercise ad-libitum energy intake is greater following evening exercise. These findings demonstrate discordant responses between subjective appetite and ad-libitum energy intake but suggest that exercise might offset circadian variations in appetite. Longer-term studies are required to determine how exercise timing affects adherence and weight management outcomes to exercise interventions. TRIAL REGISTRATION: NCT04742530, February 8, 2021.

Setting your clock: associations between timing of objective physical activity and cardiovascular disease risk in the general population

AIMS

Little is known about the impact of daily physical activity timing (here referred to as 'chronoactivity') on cardiovascular disease (CVD) risk. We aimed to examined the associations between chronoactivity and multiple CVD outcomes in the UK Biobank.

METHODS AND RESULTS

physical activity data were collected in the UK-Biobank through triaxial accelerometer over a 7-day measurement period. We used K-means clustering to create clusters of participants with similar chronoactivity irrespective of the mean daily intensity of the physical activity. Multivariable-adjusted Cox-proportional hazard models were used to estimate hazard ratios (HRs) comparing the different clusters adjusted for age and sex (model 1), and baseline cardiovascular risk factors (model 2). Additional stratified analyses were done by sex, mean activity level, and self-reported sleep chronotype. We included 86 657 individuals (58% female, mean age: 61.6 [SD: 7.8] years, mean BMI: 26.6 [4.5] kg/m2). Over a follow-up period of 6 years, 3707 incident CVD events were reported. Overall, participants with a tendency of late morning physical activity had a lower risk of incident coronary artery disease (HR: 0.84, 95%CI: 0.77, 0.92) and stroke (HR: 0.83, 95%CI: 0.70, 0.98) compared to participants with a midday pattern of physical activity. These effects were more pronounced in women (P-value for interaction = 0.001). We did not find evidence favouring effect modification by total activity level and sleep chronotype.

CONCLUSION

Irrespective of total physical activity, morning physical activity was associated with lower risks of incident cardiovascular diseases, highlighting the potential importance of chronoactivity in CVD prevention.

Time of Day and Chronotype-Dependent Synchrony Effects Exercise-Induced Reduction in Migraine Load: A Pilot Cross-Over Randomized Trial

Migraines are the most common cause of chronic pain. Effective, non-pharmacological strategies to reduce migraine load, like exercise, are needed, but it is unclear how exercise timing and chronotype modulate the effects. We sought to determine the effects of time-of-day of exercise, and synchrony with one's chronotype, on migraine load. We performed a pilot cross-over randomized trial where participants with chronic migraine completed two one-month exercise interventions, consisting of either morning exercise (before 09:00 a.m.) or evening exercise (after 7:00 p.m.) in a randomized repeated measures cross-over design (Clinical Trial #NCT04553445). Synchrony was determined by exercise time and chronotype (i.e., a morning type participant exercising in the morning is 'in-sync,' while an evening type participant exercising in the morning is 'out-of-sync'). Migraine burden, and anthropometric assessment occurred before and after each month of exercise. Data was analyzed using repeated measures ANOVA with significance accepted at p < 0.05. When comparing morning and evening exercise, there was no significant improvements in any migraine-related parameters. However, when comparing in-sync and out-of-sync exercise, we found that migraine burden was only improved following in-sync exercise, while no benefits were seen in out-of-sync exercise. Our data suggests that exercise timing has limited impact, but synchrony with chronotype may be essential to decrease migraine load in chronic migraineurs.

Impact of exercise timing on perceived appetite and food reward in early and late chronotypes: An exploratory study in a male Saudi sample

There is very limited evidence on the influence of diurnal exercise timing on appetite control, and none on food reward or how an individual's chronotype could moderate such effects. We examined the impact of acute exercise timing on perceived appetite and food reward in young Saudi adults with early or late chronotypes. Forty-five young adults (23 ± 4 years; BMI = 25.1 ± 4.0 kg/m²) completed the Morningness-Eveningness Questionnaire (MEQ) and were divided into early (score = 59 ± 5) or late (score = 41 ± 6) chronotypes. Participants attended the laboratory after ≥4 h fast on two occasions for an AM (8:00-10:00) and PM (17:00-19:00) 30-min moderate-intensity cycling bout in a randomized counterbalanced order. Appetite ratings and food reward (Arab Leeds Food Preference Questionnaire) were measured before and after exercise. An acute exercise-induced decrease in hunger was found, which appeared to be dependent upon diurnal timing and chronotype, with hunger being more suppressed after AM exercise in the early chronotypes and after PM exercise in the late chronotypes. There was greater wanting for low-fat sweet foods after AM exercise relative to PM exercise, whereas there was greater wanting for high-fat sweet food and sweet relative to savoury food after PM exercise compared to AM exercise. These preliminary findings suggest that diurnal timing of exercise impacts food preferences, and that chronotype may influence the appetite response to an exercise bout at different times of day.

The impact of a self-selected time restricted eating intervention on eating patterns, sleep, and late-night eating in individuals with obesity

Background

Time restricted eating (TRE), limiting eating to a specific daily window, is a novel dietary intervention, but the mechanisms by which TRE results in weight loss remain unclear. The goal of the current study was to examine changes in eating patterns, sleep, and late-night eating, and associations with health outcomes in a secondary analysis of a 12-week self-selected TRE intervention.

Methods

Twenty participants 18-65 years with BMI ≥25 kg/m2 completed the 12-week trial. Participants randomized to TRE (n = 11) were instructed to eat during a self-selected 8-h window, while the non-TRE group (n = 9) followed their typical eating habits. All participants logged oral intake using the myCircadian Clock mobile application throughout the entire intervention. Anthropometrics, HbA1c, an oral glucose tolerance test, and 2 weeks of actigraphy monitoring were completed at pre-intervention and end-intervention. Independent samples t-tests compared differences between groups. Data are presented as mean ± standard deviation.

Results

At preintervention, late night eating was significantly associated with higher fasting glucose (r = 0.59, p = 0.006) and higher HbA1c (r = 0.46, p = 0.016). The TRE group significantly delayed the timing of the first eating occasion by 2.72 ± 1.48 h relative to wake time (p < 0.001) and advanced the timing of the last eating occasion by 1.25 ± 0.8 h relative to bedtime (p < 0.001). The non-TRE group, on average, maintained their eating pattern. Sleep measures did not change from pre- to end-intervention, however greater restriction of the eating window was associated with longer sleep duration at end-intervention (β = -0.46 [95% CI -9.2, -0.4], p = 0.03). The TRE group significantly reduced the prevalence of late night eating (eating within 2 h of bedtime) by 14 ± 6% (p = 0.028) with 63% of participants completely eliminating late night eating at end-intervention.

Conclusion

A self-selected TRE intervention significantly shifted meal timing, reduced late-night eating while prolonging sleep duration.

Trial registry

ClinicalTrials.gov, identifier: 03129581.

A Study on the Subjectivity of Parents Regarding “0th-Period Physical Education Class” of Middle Schools in Korea Using Q-Methodology

The current study examined parents’ subjective perception types and characteristics regarding the 0th-Period Physical Education Class of Middle School in Korea. The Q-methodology was applied, and the final 25 Q-Samples were selected through the composition of the 42 Q-population. Among Korean parents, 20 students who participated in “Physical Education Activities in Class 0” for more than one year were selected as P-Sample. Q-sorting was performed by the P-Sample. Data collected by Q-sorting were analyzed using the PQ method program version 2.35, with centroid factor analysis and varimax rotation. The finding pointed to four types, with a total explanatory variance of 63%. Type 1 (N = 7), and was named “urgent legal and institutional settlement of 0th-period physical education”. Type 2 (N = 4) has the theme of “beach-head for a vibrant school life”. Type 3 (N = 4) was named “enhancement of academic capability”. Type 4 (N = 4) was described as “strengthening physical and mental health”. Moreover, the consensus statements between each type were investigated in Q1 and Q2. These findings highlight the importance of the “0th-period physical education class” so the program could be expanded and institutionalized in Korea.

Morning Exercise Reduces Abdominal Fat and Blood Pressure in Women; Evening Exercise Increases Muscular Performance in Women and Lowers Blood Pressure in Men

The ideal exercise time of day (ETOD) remains elusive regarding simultaneous effects on health and performance outcomes, especially in women.

Purpose: Given known sex differences in response to exercise training, this study quantified health and performance outcomes in separate cohorts of women and men adhering to different ETOD.

Methods: Thirty exercise-trained women (BMI = 24 ± 3 kg/m²; 42 ± 8 years) and twenty-six men (BMI = 25.5 ± 3 kg/m²; 45 ± 8 years) were randomized to multimodal ETOD in the morning (0600–0800 h, AM) or evening (1830–2030 h, PM) for 12 weeks and analyzed as separate cohorts. Baseline (week 0) and post (week 12) muscular strength (1-RM bench/leg press), endurance (sit-ups/push-ups) and power (squat jumps, SJ; bench throws, BT), body composition (iDXA; fat mass, FM; abdominal fat, Abfat), systolic/diastolic blood pressure (BP), respiratory exchange ratio (RER), profile of mood states (POMS), and dietary intake were assessed.

Results: Twenty-seven women and twenty men completed the 12-week intervention. No differences at baseline existed between groups (AM vs PM) for both women and men cohorts. In women, significant interactions (p < 0.05) existed for 1RM bench (8 ± 2 vs 12 ± 2, ∆kg), pushups (9 ± 1 vs 13 ± 2, ∆reps), BT (10 ± 6 vs 45 ± 28, ∆watts), SJ (135 ± 6 vs 39 ± 8, ∆watts), fat mass (−1.0 ± 0.2 vs −0.3 ± 0.2, ∆kg), Abfat (−2.6 ± 0.3 vs −0.9 ± 0.5, ∆kg), diastolic (−10 ± 1 vs−5 ± 5, ∆mmHg) and systolic (−12.5 ± 2.7 vs 2.3 ± 3, mmHg) BP, AM vs PM, respectively. In men, significant interactions (p < 0.05) existed for systolic BP (−3.5 ± 2.6 vs −14.9 ± 5.1, ∆mmHg), RER (−0.01 ± 0.01 vs −0.06 ± 0.01, ∆VCO₂/VO₂), and fatigue (−0.8 ± 2 vs −5.9 ± 2, ∆mm), AM vs PM, respectively. Macronutrient intake was similar among AM and PM groups.

Conclusion: Morning exercise (AM) reduced abdominal fat and blood pressure and evening exercise (PM) enhanced muscular performance in the women cohort. In the men cohort, PM increased fat oxidation and reduced systolic BP and fatigue. Thus, ETOD may be important to optimize individual exercise-induced health and performance outcomes in physically active individuals and may be independent of macronutrient intake.

Effect of Morning and Evening Exercise on Energy Balance: A Pilot Study

The purpose of this study was to evaluate the feasibility and acceptability of randomizing adults with overweight and obesity (BMI 25-40 kg/m2) to morning (06:00-10:00) or evening (15:00-19:00) aerobic exercise. Participants completed four exercise sessions per week in the morning (AM, n = 18) or evening (PM, n = 15). The exercise program was 15 weeks and progressed from 70 to 80% heart rate maximum and 750-2000 kcal/week. Bodyweight, body composition, total daily energy expenditure (TDEE), energy intake (EI), sleep, sedentary behavior (SB), non-exercise physical activity (NEPA), and maximal aerobic capacity were assessed at baseline and week 15. Study retention was 94% and adherence to the supervised exercise program was ≥90% in both groups. Weight change was -0.9 ± 2.8 kg and -1.4 ± 2.3 kg in AM and PM, respectively. AM and PM increased TDEE (AM: 222 ± 399 kcal/day, PM: 90 ± 150 kcal/day). EI increased in AM (99 ± 198 kcal/day) and decreased in PM (-21 ± 156 kcal/day) across the intervention. It is feasible to randomize adults with overweight and obesity to morning or evening aerobic exercise with high levels of adherence. Future trials are needed to understand how the timing of exercise affects energy balance and body weight regulation.

Timing of objectively-collected physical activity in relation to body weight and metabolic health in sedentary older people: a cross-sectional and prospective analysis

BACKGROUND

Little is known about the impact of timing as opposed to frequency and intensity of daily physical activity on metabolic health. Therefore, we assessed the association between accelerometery-based daily timing of physical activity and measures of metabolic health in sedentary older people.

METHODS

Hourly mean physical activity derived from wrist-worn accelerometers over a 6-day period was collected at baseline and after 3 months in sedentary participants from the Active and Healthy Ageing study. A principal component analysis (PCA) was performed to reduce the number of dimensions (e.g. define periods instead of separate hours) of hourly physical activity at baseline and change during follow-up. Cross-sectionally, a multivariable-adjusted linear regression analysis was used to associate the principal components, particularly correlated with increased physical activity in data-driven periods during the day, with body mass index (BMI), fasting glucose and insulin, HbA1c and the homeostatic model assessment for insulin resistance (HOMA-IR). For the longitudinal analyses, we calculated the hourly changes in physical activity and change in metabolic health after follow-up.

RESULTS

We included 207 individuals (61.4% male, mean age: 64.8 [SD 2.9], mean BMI: 28.9 [4.7]). Higher physical activity in the early morning was associated with lower fasting glucose (-2.22%, 95% CI: -4.19, -0.40), fasting insulin (-13.54%, 95%CI: -23.49, -4.39), and HOMA-IR (-16.07%, 95%CI: -27.63, -5.65). Higher physical activity in the late afternoon to evening was associated with lower BMI (-2.84%, 95% CI: -4.92, -0.70). Higher physical activity at night was associated with higher BMI (2.86%, 95% CI: 0.90, 4.78), fasting glucose (2.57%, 95% CI: 0.70, 4.30), and HbA1c (2.37%, 95% CI: 1.00, 3.82). Similar results were present in the prospective analysis.

CONCLUSION

Specific physical activity timing patterns were associated with more beneficial metabolic health, suggesting particular time-dependent physical activity interventions might maximise health benefits.

Subjective Perceptions and Their Characteristics of Middle School Students Regarding the Effectiveness of the “0th Period Physical Education Class” in South Korea: The Q Methodology Application

The aim of this study is to explore the subjective perception types and characteristics of Korean middle school students regarding participation in the “0th period physical education class”, a class involving physical movement that takes place before the start of regular school classes in the morning. This goal was achieved by applying the Q methodology, which can categorize the subjective viewpoints of research participants. The selection of the final 25 Q-samples was done by composing the Q-population. Twenty middle school students were selected as the P-sample, and Q-sorting was performed on them. The PQ method program (version 2.35) was used to perform centroid factor analysis and varimax rotation. The study presented five types with a total variance of 87%. Types 1 to 5 (N = 4, 4, 4, 5, and 3) pertained to a potent means of enhancing lesson concentration and academic performance, efficient activities to improve physical ability and a healthy body image in adolescence, the motivating power behind a stable school life and sociability development, building an upright character and successful changes in daily life, and raising awareness of the importance of participating in sports and the importance of physical activity, with eigenvalues (EVs) of 3.89, 4.48, 3.96, 5.16, and 2.58, respectively, and explanatory variances of 0.10, 0.22, 0.13, 0.33, and 0.09, respectively. Moreover, consensus statements for each factor were demonstrated as being Q24 and Q25. The findings in this study supported the academic foundation for the official introduction and activation of “0th period physical education classes” in the Korean education community for the near future.

Sustaining Regular Exercise During Weight Loss Maintenance: The Role of Consistent Exercise Timing

BACKGROUND

Exercising at a consistent versus variable time of day cross-sectionally relates to greater moderate to vigorous physical activity (MVPA) among weight loss maintainers. This study evaluated the relationships between exercise timing and both MVPA levels and habit strength, as well as stability in exercise timing, over 1 year among maintainers in the National Weight Control Registry.

METHODS

Participants (n = 709) completed questionnaires assessing exercise timing, MVPA, and exercise automaticity (a measure of habit) at baseline and 1-year follow-up. At each assessment, participants were labeled temporally consistent exercisers if >50% of their exercise sessions per week occurred in one time window: early morning, late morning, afternoon, or evening. Participants exercising consistently during the same window at both assessments were labeled as having stable patterns.

RESULTS

Temporally consistent exercise at baseline, regardless of its specific time, related to greater MVPA over time (Ps< .05). Approximately half of temporally consistent exercisers at baseline exhibited stable patterns. Early morning exercise and greater exercise automaticity at baseline predicted stable patterns (Ps< .005). Temporally consistent exercise, especially during the early morning, related to greater automaticity across time (Ps< .01).

CONCLUSIONS

Consistent exercise timing may help maintainers accrue more MVPA. Consistent early morning exercise was most strongly related to exercise automaticity and routine stability.

Correlates of Perceived Physical Activity Transitions during the COVID-19 Pandemic among Canadian Adults

BACKGROUND

The purpose of this study was to explore socio-ecological predictors of moderate to vigorous physical activity (MVPA) as a result of the COVD-19 pandemic restrictions.

METHOD

A representative sample of 1,055 English-speaking Canadians (18+ years) completed measures of MVPA during the COVID-19 restrictions and reflecting on MVPA prior to these restrictions, as well as demographics, COVID-19-related cognitions and behavior (i.e. perceived threat, social distancing), psychological factors (e.g. personality traits, habit, identity, strategic planning), social factors (e.g. dependent children, co-habitation), home environment affordances (exercise equipment, programming) and the neighborhood environment (e.g. access to outdoor recreation, neighborhood safety).

RESULTS

Participants perceived that they had decreased weekly MVPA (p < .01) and the availability of home equipment and strategic planning were critical predictors (p < .01). Profiles by MVPA guidelines, however, showed that 58 per cent of the sample had not changed and 6 per cent had increased MVPA. Identity was the critical predictor of the different MVPA profiles, followed by habit, extraversion, availability of home equipment, and the age of the participant (p < .01).

CONCLUSION

Pandemic restrictions have affected the MVPA of many Canadians, and variables across the socio-ecological spectrum explain who has been able to maintain MVPA during this unprecedented time.