Time of the day of exercise impact on cardiovascular disease risk factors in adults: a systematic review and meta-analysis

Impact of lifestyle moderate-to-vigorous physical activity timing on glycemic control in sedentary adults with overweight/obesity and metabolic impairments

OBJECTIVE

Moderate-to-vigorous physical activity (MVPA) improves glucose levels; however, whether its timing affects daily glycemic control remains unclear. This study aims to investigate the impact of lifestyle MVPA timing on daily glycemic control in sedentary adults with overweight/obesity and metabolic impairments.

METHODS

A total of 186 adults (50% women; age, 46.8 [SD 6.2] years) with overweight/obesity (BMI, 32.9 [SD 3.5] kg/m2) and at least one metabolic impairment participated in this cross-sectional study. MVPA and glucose patterns were simultaneously monitored over a 14-day period using a triaxial accelerometer worn on the nondominant wrist and a continuous glucose-monitoring device, respectively. Each day was classified as "inactive" if no MVPA was accumulated; as "morning," "afternoon," or "evening" if >50% of the MVPA minutes for that day were accumulated between 0600 and 1200, 1200 and 1800, or 1800 and 0000 hours, respectively; or as "mixed" if none of the defined time windows accounted for >50% of the MVPA for that day.

RESULTS

Accumulating >50% of total MVPA during the evening was associated with lower 24-h (mean difference [95% CI], -1.26 mg/dL [95% CI: -2.2 to -0.4]), diurnal (-1.10 mg/dL [95% CI: -2.0 to -0.2]), and nocturnal mean glucose levels (-2.16 mg/dL [95% CI: -3.5 to -0.8]) compared with being inactive. This association was stronger in those participants with impaired glucose regulation. The pattern of these associations was similar in both men and women.

CONCLUSIONS

These findings suggest that timing of lifestyle MVPA is significant. Specifically, accumulating more MVPA during the evening appears to have a beneficial effect on glucose homeostasis in sedentary adults with overweight/obesity and metabolic impairments.

Investigation of effects of Circadian Rhythm in Sport: A bibliometric analysis

PURPOSE

This study conducted a bibliometric analysis of the literature on circadian rhythms and sports to identify research trends, knowledge gaps, and future directions.

METHODS

A total of 301 manuscripts, including 245 articles and 56 reviews, were extracted from the Web of Science Core Collection (WoSCC) database, and the bibliometric analysis was performed using VOSviewer 1.6.16.

RESULTS

The analysis revealed a continuous increase in the volume of literature on circadian rhythms and sports over the past 38 years, with a focus on the effects of circadian rhythms on physical performance, sleep quality, and jet lag. The study identified 1107 authors who have contributed to this field, with the highest number of publications from Reilly T, Chtourou H, and Atkinson G. The publications were from 512 institutions in 59 countries/regions, with Liverpool John Moores University, University of Sfax, and Manouba University being the leading institutions. The USA, UK, and Australia had the largest number of publications. The top 3 journals were Chronobiology International, Biological Rhythm Research, and Sports Medicine.

CONCLUSION

Despite the increase in research, there are still several underexplored areas, such as the effects of circadian rhythms on cognitive and emotional processes in sports, the role of individual differences in circadian rhythms on sports outcomes, and the potential applications of circadian interventions for sports performance optimization. Future research should address these gaps to advance our understanding of the complex relationship between circadian rhythms and sports.

Study of Morpho-Functional Characteristics of the Cardiovascular System According to Electrocardiography, Phonocardiography, Echocardiography in Masters Athletics

Background

Many authors have noted the lack of knowledge on the causal relationship between the degree of physical activity, the dynamics, and outcomes of diseases, as well as the influence of sports history on the rehabilitation potential of former athletes.

Purpose

Assessment of the functional state of the cardiovascular system according to the indicators of electrocardiography, polycardiography, echocardiography and the level of physical performance in masters athletes.

Patients and Methods

The study included a main group consisting of 100 athletes, who had undergone electrocardiography, poly-electrocardiography, ultrasound echocardiography, heart rate and blood pressure measurement to determine their level of physical performance. The subjects were then divided into 2 groups. The first group included 75 people who continue to be active in regular sports activities. The second group consisted of 25 people who completely stopped training or had only occasional, unsystematic physical activities. A control group of 31 people, consisting of people of the same age who had not been involved in sports earlier, was examined according to the same program.

Results

The data obtained by us show that sports activities do contribute to the increasing stability of the body and maximize the deployment of the capabilities of the circulatory system, including their long-term preservation in masters athletic. Athletes who have stopped training have signs of age-related changes in the heart and blood vessels, which seem to be more frequent and earlier than those who continue training. A higher degree of myocardial contractility (in 90.67% of cases) can also be seen in the main group.

Conclusion

Masters athletes and those who stopped training after completing their sports career, should have notably thorough medical supervision and undergo regular annual in-depth examination.

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.

Metabolic Adaptations to Morning Versus Afternoon Training: A Systematic Review and Meta-analysis

BACKGROUND

Some physiological responses such as circulating glucose as well as muscle performance show a circadian rhythmicity. In the present study we aimed to quantitatively synthesize the data comparing the metabolic adaptations induced by morning and afternoon training.

METHODS

PubMed, SCOPUS, and Web of Science databases were systematically searched for studies comparing the metabolic adaptations (> 2 weeks) between morning and afternoon training. A meta-analysis was performed using random-effects models with DerSimonian-Laird methods for fasting blood glucose, hemoglobin A1c (HbAc1), homeostatic model assessment (HOMA), insulin, triglycerides, total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL).

RESULTS

We identified 9 studies with 11 different populations (n = 450 participants). We found that afternoon exercise was more effective at reducing circulating triglycerides [standardized mean difference (SMD) - 0.32; 95% confidence interval (CI) - 0.616 to - 0.025] than morning training. Moreover, afternoon tended to decrease fasting blood glucose (SMD - 0.24; 95% CI - 0.478 to 0.004) to a greater extent than morning training.

CONCLUSION

Metabolic adaptations to exercise may be dependent on the time of day. Morning training does not show superior effects to afternoon exercise in any of the analyzed outcomes. However, afternoon training is more effective at reducing circulating triglyceride levels and perhaps at reducing fasting blood glucose than morning training. The study was preregistered at PROSPERO (CRD42021287860).