Effects of exercise timing on sleep architecture and nocturnal blood pressure in prehypertensives

Physical activity and happiness of college students: chain mediating role of exercise attitude and sleep quality

Introduction

This study explores the role of physical activity, exercise attitude, and sleep quality in college students' happiness, aiming to provide a theoretical basis for improving college students' mental health.

Methods

The study employed a whole group sampling method, utilizing a physical activity level scale, exercise attitude scale, sleep quality scale, and happiness scale. A questionnaire survey was conducted with 1,308 college students from four universities in China.

Results

The analysis yielded three key findings: (1) Physical activity significantly improves college students' happiness, and this improvement can be achieved through direct and indirect effects. (2) Positive exercise attitude plays an important mediating role between physical activity and happiness, and a high level of exercise attitude can enhance happiness. In addition, the effect of physical activity on happiness is most significant through exercise attitude. (3) Although sleep quality did not significantly mediate the relationship between physical activity and happiness alone, it played a positive role in the chain mediation path of "physical activity → exercise attitude → sleep quality → happiness."

Discussion

The discovery of the chain mediation path shows that physical activity not only affects happiness, but also indirectly affects college students' happiness through the combined effects of psychological and physiological factors.

The effects of morning versus evening high-intensity interval exercise on the magnitude of the morning blood pressure surge

Blood pressure (BP) follows a circadian rhythm, dipping during sleep and surging in the morning. A larger morning BP surge is an independent predictor of cardiovascular events. Acute exercise can produce sustained periods of post-exercise hypotension that last up to 24 h; however, the timing of exercise (morning vs. evening) may influence this response. Whether the timing of exercise influences the morning BP surge remains unknown. The current study investigated the effects of a bout of high-intensity interval exercise (HIIE) performed in the morning versus evening on the magnitude of the morning BP surge in young healthy adults. Twenty-six young, otherwise healthy adults (23 ± 4 years; 15 females) completed a randomized crossover trial where, on different days, they completed a no exercise control visit or performed either morning (0800-1000 h) or evening (1700-1900 h) HIIE. Following each visit, ambulatory BP was assessed in 30 min intervals for 24 hrs. HIIE at either time did not alter the magnitude of the morning BP surge compared to control values (control: 22 ± 5 mmHg; morning exercise: 20 ± 8 mmHg; evening exercise: 22 ± 10 mmHg, P = 0.40) or when grouped separately by sex (visit × sex P = 0.42). A positive correlation existed between Morningness-Eveningness Questionnaire score and the change in nighttime BP following both exercise times (both r = 0.42 and P = 0.04). These findings suggest that HIIE does not attenuate the morning BP surge in young healthy adults and that chronotype can predict nighttime BP responses following HIIE, irrespective of exercise time of day. This study was registered on ClinicalTrials.gov (NCT06702930).

Impact of ischemic preconditioning combined with aerobic exercise on 24-h ambulatory blood pressure in men with prehypertension and stage 1 hypertension

Introduction

A single bout of aerobic exercise is known to induce a temporary reduction in post-exercise blood pressure termed post-exercise hypotension (PEH). Meanwhile, an ischemic preconditioning (IPC), a series of short ischemia-reperfusion intervention, has also shown antihypertensive effects showing a potential nonpharmacologic intervention for hypertension. While the acute BP reduction effects of aerobic exercise and IPC are individually well-investigated, it remains unclear if combining both interventions has an additive effect on PEH.

Methods

A total of twelve pre- or hypertensive men (six prehypertension, six stage 1 hypertension) underwent either 30 min of aerobic exercise at 50% VO2peak (CON) or IPC before exercise, in a counterbalanced order. IPC involved inflating cuffs on both thighs to 200 mmHg for 5 min, alternating between right and left thighs for three cycles, totaling 30 min. Brachial BP was measured during exercise and 1-h post-exercise recovery whereas muscle oxygen saturation (SmO2) from the rectus femoris was monitored using NIRs during exercise and recovery. Heart rate variability (HRV) and baroreflex sensitivity (BRS) together with a head-up tilt test (at 0 and 50°) were measured at the pre-test, post-test, and 24-h post-test. After the completion of each experiment, 24-h ambulatory blood pressure (ABP) was monitored to assess post-exercise hypotension within a 24-h window.

Results

BP and heart rate responses during exercise and 1-h recovery did not differ between conditions while SmO2 was significantly elevated during exercise in IPC (p = 0.004). There was no difference in HRV and supine BRS. However, significantly reduced titled BRS after exercise was found in CON while IPC preserved BRS similar to pre-exercise value, extending to 24-h post period (p = 0.047). ABP monitoring revealed a significant reduction in systolic BP during sleep in IPC compared to CON (p = 0.046).

Conclusion

The present findings suggest that IPC with a single session of aerobic exercise results in a notable decrease in systolic ABP, particularly during sleep, compared to aerobic exercise alone. This supplementary antihypertensive effect was associated with a sustained BRS, persisting up to 24 h in contrast to the significant decrease observed in CON. Future studies are warranted to investigate long-term adaptations to IPC.

Inter-Individual Responses to Acute Resistance Training in the Blood Pressure Dipping Response in Normotensive and Hypertensive Men

The blood pressure dipping response to acute resistance training exercise (RTE) is scarce in the literature. We determined the inter-individual blood pressure (BP) dipping variability of normotensive (NT) and hypertensive (HT) men completing two modalities of a single session of RTE. Volunteers (NT n = 21, HT n = 20) underwent a non-exercise control (CTRL), RTE high-sets low-repetitions (HSLR), and RTE high-repetitions low-sets (HRLS) conditions. Twenty-four-hour ambulatory BP monitoring recorded diurnal and nocturnal systolic (SBP) and diastolic (DBP) BP. Non-significant interactions were found between the category of individuals and the experimental conditions on the SBP (p = 0.511, η2 p = 0.02) and DBP (p = 0.807, η2 p = 0.01) differences. Diurnal SBP (p = 0.0001) and DBP (p ≤ 0.0001) were lower in the NT than in the HT groups. Nocturnal SBP (p ≤ 0.0001) and DBP (p = 0.014) were lower in the NT than in the HT groups. The percentage of dipping responders for SBP in the CTRL condition were 71.4% for NT and 70.0% for HT, in the HRLS condition were 66.7% for NT and 60.0% for HT, and in the HSLR condition were 57.1% for NT and 60.0% for HT. The dipping responders for DBP in the CTRL condition were 57.1% for NT and 60.0% for HT, in the HRLS condition were 61.9% for NT and 70.0% for HT, and in the HSLR condition were 71.4% for NT and 65.0% for HT (p > 0.05 for all). In conclusion, the dipping response was similar between NT and HT individuals. The proportion of responders was similar between NT and HT individuals completing acute RTE.

Clusters of lifestyle behavioral risk factors and their associations with depressive symptoms and stress: evidence from students at a university in Finland

BACKGROUND

No previous research of university students in Finland assessed lifestyle behavioral risk factors (BRFs), grouped students into clusters, appraised the relationships of the clusters with their mental well-being, whilst controlling for confounders. The current study undertook this task.

METHODS

Students at the University of Turku (n = 1177, aged 22.96 ± 5.2 years) completed an online questionnaire that tapped information on sociodemographic variables (age, sex, income sufficiency, accommodation during the semester), four BRFs [problematic alcohol consumption, smoking, food consumption habits, moderate-to-vigorous physical activity (MVPA)], as well as depressive symptoms and stress. Two-step cluster analysis of the BRFs using log-likelihood distance measure categorized students into well-defined clusters. Two regression models appraised the associations between cluster membership and depressive symptoms and stress, controlling for sex, income sufficiency and accommodation during the semester.

RESULTS

Slightly more than half the study participants (56.8%) had always/mostly sufficient income and 33% lived with parents/partner. Cluster analysis of BRFs identified three distinct student clusters, namely Cluster 1 (Healthy Group), Cluster 2 (Smokers), and Cluster 3 (Nonsmokers but Problematic Drinkers). Age, sex and MVPA were not different across the clusters, but Clusters 1 and 3 comprised significantly more respondents with always/mostly sufficient income and lived with their parents/partner during the semester. All members in Clusters 1 and 3 were non-smokers, while all Cluster 2 members comprised occasional/daily smokers. Problematic drinking was significantly different between clusters (Cluster 1 = 0%, Cluster 2 = 54%, Cluster 3 = 100%). Cluster 3 exhibited significantly healthier nutrition habits than both other clusters. Regression analysis showed: (1) males and those with sufficient income were significantly less likely to report depressive symptoms or stress; (2) those living with parents/partner were significantly less likely to experience depressive symptoms; (3) compared to Cluster 1, students in the two other clusters were significantly more likely to report higher depressive symptoms; and (4) only students in Cluster 2 were more likely to report higher stress.

CONCLUSIONS

BRFs cluster together, however, such clustering is not a clear-cut, all-or-none phenomenon. Students with BRFs consistently exhibited higher levels of depressive symptoms and stress. Educational and motivational interventions should target at-risk individuals including those with insufficient income or living with roommates or alone.

The SAFE study: Stress and fatigue control by exercise: Acute and long-term effects of aerobic exercise in lactating employed mothers

BACKGROUND

Stress and fatigue experienced by lactating employed mothers can affect mothers' and babies' mental and physical health detrimentally. Aerobic exercise is known to control stress and fatigue, but the dosages of the exercises needed to maintain long-term effects are still under investigation.

OBJECTIVE

This study aimed to investigate the acute and long-term effects of aerobic exercise on controlling stress and fatigue in lactating, employed mothers.

METHODS

This randomized control study involved sixty lactating, employed mothers suffering from stress and fatigue. They were divided into two groups: Group A received five sessions of 30-minute aerobic training on a treadmill per week, in addition to lifestyle modification advice for six weeks. Group B received the same lifestyle routine advice for the same duration without being trained. Assessments of stress and fatigue levels were done before, after 6 weeks, and after 6 months from the baseline assessments using the Perceived Stress Scale (PSS-10) and Fatigue Assessment Scale (FAS), respectively.

RESULTS

Post-six-week comparisons within and between both groups showed a significant decline in PSS-10 and FAS in group A compared with group B (p < 0.001); however, after six months of follow-up, there were statistically significant effects within groups only (p < 0.05) and no statistically significant difference between groups at both variables (p > 0.05).

CONCLUSION

Aerobic exercises for 6 weeks can induce an acute but not long-term effect on stress and fatigue control in lactating-employed mothers. Future research is needed to tailor the exercise prescription needed to maintain training's long-term benefits.

The Effect of Physical Activity on Sleep Quality and Sleep Disorder: A Systematic Review

Regular physical activity has several health benefits, including improved sleep quality and symptoms of sleep disorders. With the known benefits of moderate-intensity activities to sleep quality and a growing interest in using physical activity as a treatment approach for different sleep disorders, we conducted a systematic review to provide evidence-based data on the association between physical activity and sleep. A systematic search was carried out in PubMed, Embase, MEDLINE (Medical Literature Analysis and Retrieval System Online), Google Scholar, and Scopus, using predetermined search terms (Medical Subject Headings (MeSH) terms) and keywords. The included studies focused on exploring the effect of physical activity on sleep quality and sleep disorders or the association between physical activity and sleep outcomes. Relevant data were extracted, and the quality of the studies was evaluated using suitable methods. The collected findings were synthesized and discussed. The findings of this systematic review have potential implications for healthcare, public health policies, and health promotion.

Role of Physical Activity on Mental Health and Well-Being: A Review

In addition to the apparent physical health benefits, physical activity also affects mental health positively. Physically inactive individuals have been reported to have higher rates of morbidity and healthcare expenditures. Commonly, exercise therapy is recommended to combat these challenges and preserve mental wellness. According to empirical investigations, physical activity is positively associated with certain mental health traits. In nonclinical investigations, the most significant effects of physical exercise have been on self-concept and body image. An attempt to review the current understanding of the physiological and psychological mechanisms by which exercise improves mental health is presented in this review article. Regular physical activity improves the functioning of the hypothalamus-pituitary-adrenal axis. Depression and anxiety appear to be influenced by physical exercise, but to a smaller extent in the population than in clinical patients. Numerous hypotheses attempt to explain the connection between physical fitness and mental wellness. Physical activity was shown to help with sleep and improve various psychiatric disorders. Exercise in general is associated with a better mood and improved quality of life. Physical exercise and yoga may help in the management of cravings for substances, especially in people who may not have access to other forms of therapy. Evidence suggests that increased physical activity can help attenuate some psychotic symptoms and treat medical comorbidities that accompany psychotic disorders. The dearth of literature in the Indian context also indicated that more research was needed to evaluate and implement interventions for physical activity tailored to the Indian context.

The role of sleep in PCOS: what we know and what to consider in the future

INTRODUCTION

Sleep disturbance and clinical sleep conditions disrupt endocrine signals, energy expenditure and nutritional intake. Women with polycystic ovary syndrome (PCOS) are at higher risk of sleep disturbances and clinical conditions. It is possible that sleep may contribute to the exacerbation of PCOS. This review aims to explore the relationship between sleep and chronic disease, particularly in women with PCOS.

AREAS COVERED

This review narratively explores what sleep is, how to measure sleep and the possible mechanisms that support the link between sleep in adipose tissue deposition, insulin resistance and the presentation of PCOS.

EXPERT OPINION

Research shows that disturbed sleep and clinical sleep conditions disrupt energy expenditure. This may increase adipose tissue deposition and exacerbate insulin resistance which are known to worsen the presentation of PCOS. Further, sleep disturbance in women with PCOS may ameliorate any positive lifestyle changes made after diagnosis. Cognitive behavioural therapy interventions for sleep are a successful strategy for the management of sleep disturbances in the general population. However, such interventions are yet to be trialled in women with PCOS. Given the proposed implications, interventions to improve sleep could provide additional support for women with PCOS to successfully implement lifestyle strategies and should be further investigated.

Sleep Quality: A Narrative Review on Nutrition, Stimulants, and Physical Activity as Important Factors

Sleep is a cyclically occurring, transient, and functional state that is controlled primarily by neurobiological processes. Sleep disorders and insomnia are increasingly being diagnosed at all ages. These are risk factors for depression, mental disorders, coronary heart disease, metabolic syndrome, and/or high blood pressure. A number of factors can negatively affect sleep quality, including the use of stimulants, stress, anxiety, and the use of electronic devices before sleep. A growing body of evidence suggests that nutrition, physical activity, and sleep hygiene can significantly affect the quality of sleep. The aim of this review was to discuss the factors that can affect sleep quality, such as nutrition, stimulants, and physical activity.

Exercise as a Peripheral Circadian Clock Resynchronizer in Vascular and Skeletal Muscle Aging

Aging is characterized by several progressive physiological changes, including changes in the circadian rhythm. Circadian rhythms influence behavior, physiology, and metabolic processes in order to maintain homeostasis; they also influence the function of endothelial cells, smooth muscle cells, and immune cells in the vessel wall. A clock misalignment could favor vascular damage and indirectly also affect skeletal muscle function. In this review, we focus on the dysregulation of circadian rhythm due to aging and its relationship with skeletal muscle changes and vascular health as possible risk factors for the development of sarcopenia, as well as the role of physical exercise as a potential modulator of these processes.

Examining the Role of Exercise Timing in Weight Management: A Review

Many adults cite exercise as a primary strategy for losing weight, yet exercise alone is modestly effective for weight loss and results in variable weight loss responses. It is possible that some of the variability in weight loss may be explained by the time of day that exercise is performed. Few studies have directly compared the effects of exercise performed at different times of the day (i. e., morning versus evening exercise). Results from these existing studies are mixed with some studies demonstrating superior weight and fat mass loss from morning exercise, while other studies have found that evening exercise may be better for weight management. Exercise timing may alter modifiable lifestyle behaviors involved in weight management, such as non-exercise physical activity, energy intake, and sleep. The purpose of this review is to summarize evidence for and against time-of-day dependent effects of exercise on weight management. Although limited, we also review studies that have examined the effect of exercise timing on other lifestyle behaviors linked to body weight regulation. While exercise at any time of day is beneficial for health, understanding whether there is an optimal time of day to exercise may advance personalized treatment paradigms for weight management.

Using Predicted Atherosclerotic Cardiovascular Disease Risk for Discrimination of Awake or Nocturnal Hypertension

BACKGROUND

Several atherosclerotic cardiovascular disease (ASCVD) risk factors are associated with awake and nocturnal hypertension.

METHODS

We assessed the association between a composite ASCVD risk score and awake or nocturnal hypertension using data from participants aged 40-79 years who completed ambulatory blood pressure monitoring at the Year 30 Coronary Artery Risk Development in Young Adults study exam in 2015-2016 (n = 716) and the baseline Jackson Heart Study exam in 2000-2004 (n = 770). Ten-year predicted ASCVD risk was calculated using the Pooled Cohort risk equations. Awake hypertension was defined as mean awake systolic blood pressure (SBP) ≥135 mm Hg or diastolic blood pressure (DBP) ≥85 mm Hg and nocturnal hypertension was defined as mean asleep SBP ≥120 mm Hg or DBP ≥70 mm Hg.

RESULTS

Among participants with a 10-year predicted ASCVD risk <5%, 5% to <7.5%, 7.5% to <10%, and ≥10%, the prevalence of awake or nocturnal hypertension as a composite outcome was 29.5%, 47.8%, 62.2%, and 69.7%, respectively. After multivariable adjustment, higher ASCVD risk was associated with higher prevalence ratios for awake or nocturnal hypertension among participants with clinic-measured SBP/DBP <130/85 mm Hg but not ≥130/85 mm Hg. The C-statistic for discriminating between participants with vs. without awake or nocturnal hypertension was 0.012 (95% confidence interval 0.003, 0.016) higher when comparing a model with ASCVD risk and clinic-measured blood pressure (BP) together vs. clinic-measured BP without ASCVD risk.

CONCLUSIONS

Using 10-year predicted ASCVD risk in conjunction with clinic BP improves discrimination between individuals with and without awake or nocturnal hypertension.

The Effect of Timing and Type of Exercise on the Quality of Sleep in Trained Individuals

Sleep is an extremely important component for overall health and for a well-balanced training program. Recent studies have highlighted the interaction between sleep, recovery, and performance in elite and recreational athletes alike. Exercise has been known to affect the quality of sleep, nevertheless the impact is not well understood in the current research, particularly the effects of exercise timing and intensity on sleep quality. The purpose of this study was to understand if exercise timing and intensity significantly impact sleep quality among recreational exercisers. The participants involved were recreational exercisers who were self-grouped into an AM or PM exercise group. They participated in a seven-day quantitative, quasi-experimental, exploratory study wearing an Actigraph watch. The participant's intensity was also self-grouped into moderate intensity or high intensity based on criteria cut points. Data was analyzed using a factorial ANOVA to examine if there was a significant difference between exercise timing and intensity on sleep quality of the participants. There were no significant differences in sleep quality in either the time group (AM vs PM) or the intensity group (MOD vs VIG) within the four measures of sleep that were looked at throughout this study; total sleep time, sleep onset latency, sleep efficiency % and wake after sleep onset (TST, SOL, SE, and WASO). Results within both, the AM and PM group and the MOD and VIG group, results showed no significant differences. These results conclude that neither exercise intensity or timing had an effect on sleep quality.

Association of Daily Rest-Activity Patterns With Adiposity and Cardiometabolic Risk Measures in Teens

PURPOSE

Emerging data indicate that the timing and rhythms of energetic behaviors may influence metabolism and obesity risk. Our aim was to derive diurnal rest-activity patterns from actigraphy in adolescents and analyze associations with adiposity measures and cardiometabolic risk factors.

METHODS

Adolescents in the Project Viva cohort wore a wrist actigraph over 7 days. We derived markers of daily rest-activity patterns from actigraphy using nonparametric models, generating measurements of relative amplitude (RA). RA reflects the normalized difference in activity measured during the most active 10-hour period and the least active 5-hour period, averaged over multiple 24-hour periods. Using multivariable-adjusted linear regression models, we estimated associations of RA and its components with markers of adiposity (body mass index, waist circumference, skinfolds, dual-energy X-ray absorptiometry fat mass) and cardiometabolic health (cardiometabolic risk score, derived as the mean of five sex-specific internal z-scores for waist circumference, systolic blood pressure, high-density lipoprotein cholesterol scaled inversely, and log-transformed triglycerides and homeostatic model assessment of insulin resistance).

RESULTS

A total of 778 adolescents provided at least 5 days of valid actigraphy data. The average age was 13.2 (±.9) years, 52% were female, and the average RA was .9 (±.1). A higher RA reflecting higher activity during wakefulness and lower activity during the night was associated with more favorable indices of adiposity (e.g., -.35 kg/m² lower body mass index per each .04 units increment of RA; 95% confidence interval: -.60 to -.09).

CONCLUSIONS

In this large sample of adolescents, a higher RA emerged as a novel biomarker, associated with more favorable cardiometabolic profiles.

Exercise time cues (zeitgebers) for human circadian systems can foster health and improve performance: a systematic review

Background

Circadian system time cues (zeitgebers) acting synergistically at the right times can foster chronobiological homeostasis and ultimately health. Modern 24/7 societies are challenging chronobiological homeostasis and public health. Exercise has been discussed as a potential zeitgeber for the human circadian system. Thus, if timed correctly, exercise may help in maintenance of chronobiological homeostasis and foster public health amidst increasingly challenging 24/7 lifestyles.

Objective

To test, using a systematic review of the literature, the following hypothesis: exercise is a zeitgeber for the human circadian system.

Data sources

The PubMed database was systematically searched on 19 October 2017 for relevant scientific studies and reports concerning chronobiology and exercise. Eligibility criteria were defined to include articles considering exercise as a potential zeitgeber for human circadian rhythmicity or chronobiological effects of exercise on health and/or physical performance. Cognitive effects and effects on children were excluded from the synthesis.

Results

Our systematic literature search and synthesis is compatible with the validity of the hypothesis. We report that potential exercise-zeitgeber properties may be used to improve health and performance.

Conclusions

Informed timing of exercise, specific to the circadian rhythm phase and zeitgeber exposure of the individual, must be advocated in performance and disease contexts as an adjunct therapeutic or preventative strategy and physical enhancer.

Circadian Rhythms, Exercise, and Cardiovascular Health

Human circadian rhythmicity is driven by a circadian clock comprised of two distinct components: the central clock, located in the suprachiasmatic nucleus (SCN) within the hypothalamus, and the peripheral clocks, located in almost all tissues and organ systems in the body. Entrainment, or alignment, of circadian rhythmicity is dependent upon time of day and can occur through environmental influences such as light cues and physical activity exerted on skeletal muscle. Entrainment of the circadian clock through exercise has been reported to improve health by reducing risk of conditions such as cardiovascular disease (CVD), but further research is still needed. The purpose of this review is to discuss the effects exercise has on the regulation of circadian rhythmicity, specifically with respect to CVD risk factors – including hormonal levels, sleep/wake cycles, blood pressure, and heart rate. Additionally, the impact of exercise-induced circadian entrainment is discussed relative to hormone regulation, nocturnal blood pressure dipping, post-exercise hypotension, and overall cardiovascular health.

Impact of physical exercise in cancer survivors during and after antineoplastic treatments

Cancer patients experience symptoms and adverse effects of treatments that may last even after the end of treatments. Exercise is a safe, non-pharmacological and cost-effective therapy that can provide several health benefits in cancer patient and survivors, reducing cancer symptoms and cancer treatment side effects. The purpose of this review is to describe how the physical exercise is capable to reduce cancer symptoms and cancer treatment side effects. We realized a pragmatic classification of symptoms, dividing them into physical, psychological and psycho-physical aspects. For each symptom we discuss causes, therapies, we analyse the effects of physical exercise and we summarize the most effective type of exercise to reduce the symptoms. This review also points out what are the difficulties that patients and survivors face during the practice of physical activity and provides some solutions to overcome these barriers. Related to each specific cancer, it emerges that type, frequency and intensity of physical exercise could be prescribed and supervised as a therapeutic program, like it occurs for the type, dose and duration of a drug treatment.

The relations between sleep, time of physical activity, and time outdoors among adult women

Physical activity and time spent outdoors may be important non-pharmacological approaches to improve sleep quality and duration (or sleep patterns) but there is little empirical research evaluating the two simultaneously. The current study assesses the role of physical activity and time outdoors in predicting sleep health by using objective measurement of the three variables. A convenience sample of 360 adult women (mean age = 55.38 ±9.89 years; mean body mass index = 27.74 ±6.12) was recruited from different regions of the U.S. Participants wore a Global Positioning System device and ActiGraph GT3X+ accelerometers on the hip for 7 days and on the wrist for 7 days and 7 nights to assess total time and time of day spent outdoors, total minutes in moderate-to-vigorous physical activity per day, and 4 measures of sleep health, respectively. A generalized mixed-effects model was used to assess temporal associations between moderate-to-vigorous physical activity, outdoor time, and sleep at the daily level (days = 1931) within individuals. There was a significant interaction (p = 0.04) between moderate-to-vigorous physical activity and time spent outdoors in predicting total sleep time but not for predicting sleep efficiency. Increasing time outdoors in the afternoon (versus morning) predicted lower sleep efficiency, but had no effect on total sleep time. Time spent outdoors and the time of day spent outdoors may be important moderators in assessing the relation between physical activity and sleep. More research is needed in larger populations using experimental designs.

Interrelationship between Sleep and Exercise: A Systematic Review

Although a substantial body of literature has explored the relationship between sleep and exercise, comprehensive reviews and definitive conclusions about the impact of exercise interventions on sleep are lacking. Electronic databases were searched for articles published between January 2013 and March 2017. Studies were included if they possessed either objective or subjective measures of sleep and an exercise intervention that followed the guidelines recommended by the American College of Sports Medicine. Thirty-four studies met these inclusion criteria. Twenty-nine studies concluded that exercise improved sleep quality or duration; however, four found no difference and one reported a negative impact of exercise on sleep. Study results varied most significantly due to participants' age, health status, and the mode and intensity of exercise intervention. Mixed findings were reported for children, adolescents, and young adults. Interventions conducted with middle-aged and elderly adults reported more robust results. In these cases, exercise promoted increased sleep efficiency and duration regardless of the mode and intensity of activity, especially in populations suffering from disease. Our review suggests that sleep and exercise exert substantial positive effects on one another; however, to reach a true consensus, the mechanisms behind these observations must first be elucidated.

Lifestyle and Risk of Hypertension: Follow-Up of a Young Pre-Hypertensive Cohort

OBJECTIVES

To determine whether healthy lifestyle decreases the risk of developing hypertension in pre-hypertensive patients.

STUDY DESIGN

A longitudinal study.

SETTING & PARTICIPANTS

Randomly selected pre-hypertensive young adults 20-45 years old without any vascular disease such as stroke or diabetes.

PREDICTORS

Four lifestyle factors (a body mass index [BMI] of 18.5-24.9 kg/m2, regular physical activity, no alcohol use and 6-8 h of sleep per day), individually and in combination.

OUTCOMES

Hypertension was defined as a systolic blood pressure (SBP) ≥ 140 mmHg, or a diastolic BP (DBP) ≥ 90 mmHg or self-reported hypertension.

MEASUREMENTS

Multivariate adjusted Cox proportional hazards.

RESULTS

During a median follow-up of 4.7 years, 1009 patients were enrolled in our study, and 182 patients developed hypertension. Compared with a BMI of 18.5-24.9 kg/m2, a BMI of 25-30 kg/m2 and a BMI of >30 kg/m2 were associated with an increased risk of hypertension occurrence (hazard ratio [HR], 1.83; 95% confidence interval [CI], 1.19-2.84 and HR, 2.62; 95% CI, 1.01-6.80, respectively). Compared with sleep duration of >8 h/day, 6-8 h/day of sleep was associated with a lower risk of hypertension occurrence (HR, 0.40; 95% CI, 0.18-0.86). There were no statistically significant associations between physical activity or alcohol use and hypertension occurrence (P>0.05).

LIMITATION

All lifestyle factors were measured only once.

CONCLUSION

Healthy BMI (18.5-24.9 kg/m(2)) and sleep duration (6-8 h/day) were associated with a lower risk of the occurrence of hypertension in pre-hypertension patients.