Fitness-related physical activity intensity explains most of the association between accelerometer data and cardiometabolic health in persons 50-64 years old.

OBJECTIVES: To investigate the physical activity (PA) intensity associated with cardiometabolic health when considering the mediating role of cardiorespiratory fitness (CRF). METHODS: A subsample of males and females aged 50-64 years from the cross-sectional Swedish CArdioPulmonary bioImage Study was investigated. PA was measured by accelerometry and CRF by a submaximal cycle test. Cardiometabolic risk factors, including waist circumference, systolic blood pressure, high-density lipoprotein, triglycerides and glycated haemoglobin, were combined to a composite score. A mediation model by partial least squares structural equation modelling was used to analyse the role of CRF in the association between PA and the composite score. RESULTS: The cohort included 4185 persons (51.9% female) with a mean age of 57.2 years. CRF mediated 82% of the association between PA and the composite score. The analysis of PA patterns revealed that moderate intensity PA explained most of the variation in the composite score, while vigorous intensity PA explained most of the variation in CRF. When including both PA and CRF as predictors of the composite score, the importance of vigorous intensity increased. CONCLUSION: The highly interconnected role of CRF in the association between PA and cardiometabolic health suggests limited direct effects of PA on cardiometabolic health beyond its impact on CRF. The findings highlight the importance of sufficient PA intensity for the association with CRF, which in turn is linked to better cardiometabolic health.

Change in cardiorespiratory fitness and risk of depression, anxiety, and cerebrovascular disease.

INTRODUCTION: High cardiorespiratory fitness (CRF) has been associated with a lower risk of depression, anxiety, and cerebrovascular disease. The aim was to explore CRF changes over time associated with these outcomes. METHODS: This large-scale prospective cohort study, using data from Swedish population-wide registries and databases (during 1972-2020), included men (n=131,431), with measures of estimated CRF (estCRF) in late adolescence (maximal cycle test) and adulthood (sub-maximal cycle test) (mean years between 24.6, SD 8.8). The study explored how change in estCRF was associated with incident depression, anxiety, and cerebrovascular disease using Cox proportional hazards models. Analyses were performed in 2023. RESULTS: Higher estCRF in late adolescence and adulthood were associated with a lower risk of incident depression, anxiety, and cerebrovascular disease later in life. For all three outcomes, an increase in estCRF (ml/min/kg and z-score) between the two time points was associated with a lower risk. Further, decreasing from moderate or high estCRF in adolescence to low estCRF in adulthood, compared to staying at a moderate or high level, was associated with a higher risk of depression and anxiety (HR:1.24 95%CI 1.07-1.45 and 1.25 95%CI 1.06-1.49, respectively). Conversely, increasing from moderate to high estCRF was associated with a lower risk of incident anxiety (HR:0.84 95%CI 0.71-0.99). CONCLUSIONS: The findings indicate that there is a longitudinal association between negative change in estCRF and increased risk of depression, anxiety, and cerebrovascular disease later in life. Decreasing levels of estCRF could be a helpful indicator when identifying these disorders at a population level.

Reliability in Novel Field-Based Fitness Measurements and Postexercise Scores from a Physical Fitness Test Battery in Older Adults.

INTRODUCTION: Physical fitness is strongly associated with daily physical function, health, and longevity in older adults. Field-based tests may provide a reasonable alternative compared to advanced laboratory testing. Separating postexercise test scores from reactivity measurements requires sufficient test-retest reliability. Postexercise test scores with reliability analyses of field-based fitness tests in older adults are lacking. The present study aimed to examine the test-retest reliability of some novel easily accommodated fitness test measurements and compare pretest scores with postexercise results in these tests along with other field-based fitness tests in older adults. METHODS: Totally 1,407 community-dwelling older adults (69% female), x̄ = 71.5 ± 5.0 (65-84 years), performed twelve field-based fitness tests at pretest 1, pretest 2 and a posttest after an 8-week exercise period (twice weekly 1 h of combined strength and aerobic training). T tests, intra-class correlation, limits of agreement, standard error of measurement, and coefficient of variance were performed between pre-1 and pre-2 tests, and repeated measures ANOVA and partial eta squared effect size for postexercise differences for men and women in 5-year age groups ranging from 65 to 84 years. RESULTS: Between pre-1 and pre-2 tests a significant difference was noted in some of the novel fitness test measurements but generally not, e.g., in isometric trunk flexion and step-up height on either leg among all sex and age groups. In most of these novel fitness test measurements, no significant differences occurred between the two pretests. Examples of results from the pre-2 test to the posttest were isometric trunk flexion 45° endurance and isometric trunk extension endurance improved significantly for both sexes in age groups 65-74 years. Women, but not men, improved the maximal step-up height for both legs in most age groups. The speed in the 50 sit-to-stand improved significantly for most age groups in both sexes. Six-min walk distance improved significantly for most age groups in women but among men only in 65-69 years. In the timed-up-and-go test, significant improvements were seen for all age groups in women and in men 70-79 years. No postexercise improvements were generally observed for grip strength or balance. CONCLUSIONS: In most of the novel fitness test measures, no significant difference was noted between the two pretests in the assessed sex and age groups. Results after the 8-week exercise period varied between sex and age groups, with significant improvements in several of the twelve studied fitness tests. These findings may be valuable for future projects utilizing easily accommodated physical fitness tests in older adults.

Associations of device-measured and self-reported physical activity with alcohol consumption: Secondary analyses of a randomized controlled trial (FitForChange).

BACKGROUND: Physical activity (PA) is increasingly used as an adjunct treatment for alcohol use disorder (AUD). Previous studies have relied on self-report measures of PA, which are prone to measurement error. In the context of a randomized controlled trial of PA for AUD, we examined: (1) associations between device-measured and self-reported PA, (2) associations between PA measurements and alcohol use, and (3) the feasibility of obtaining device-measured PA data in this population. METHOD: One-hundred and forty individuals with clinician-diagnosed AUD participated in a 12-week intervention comparing usual care (phone counselling) to yoga-based exercise and aerobic exercise. Device-measured PA (Actigraph GT3x), self-reported PA (International Physical Activity Questionnaire) and alcohol consumption (Timeline Follow Back Method) were assessed before and after the trial. Effects of the interventions on PA levels were assessed using linear mixed models. RESULTS: In total, 42% (n=59) of participants returned usable device-measured PA data (mean age= 56±10 years, 73% male). Device-measured and self-reported vigorous-intensity PA were correlated (ß= -0.02, 95%CI= -0.03, -0.00). No associations were found for moderate-intensity PA. Compared to usual care, time spent in device-measured light-intensity PA increased in the aerobic exercise group (∆= 357, 95%CI= 709, 5.24). Increases in device-measured light-intensity PA were associated with fewer standard drinks (∆= -0.24, 95%CI= -0.03, -0.44), and fewer heavy drinking days (∆= -0.06, 95%CI=-0.01, -0.10). CONCLUSION: Increases in light-intensity/habitual PA were associated with less alcohol consumption in adults with AUD. Self-reported PA data should be interpreted with caution. Incentives are needed to obtain device-measured PA data in AUD populations.

Cardiorespiratory fitness and the association with galectin-1 in middle-aged individuals.

Galectin-1 plays a functional role in human metabolism and the levels are altered in obesity and type 2 diabetes (T2D). This study investigates the association of cardiorespiratory fitness (CRF) with galectin-1 and the interconnection with body fatness. Cross-sectional data from the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot was analyzed, including a sample of 774 middle-aged individuals. A submaximal cycle ergometer test was used to estimate CRF as an indirect measure of the physical activity (PA) level. Serum-galectin-1 concentration was determined from venous blood collected after an overnight fast. Body mass index (BMI) was used as an indirect measure of body fatness. CRF was significantly associated with galectin-1, when controlled for age and sex (regression coefficient (regr coeff) = -0.29, p<0.001). The strength of the association was attenuated when BMI was added to the regression model (regr coeff = -0.09, p = 0.07), while the association between BMI and galectin-1 remained strong (regr coeff = 0.40, p<0.001). CRF was associated with BMI (regr coeff = -0.50, p<0.001). The indirect association between CRF and galectin-1 through BMI (-0.50 x 0.40) contributed to 69% of total association (mediation analysis). In group comparisons, individuals with low CRF-high BMI had the highest mean galectin-1 level (25 ng/ml), while individuals with high CRF-low BMI had the lowest level (21 ng/ml). Intermediate levels of galectin-1 were found in the low CRF-low BMI and high CRF-high BMI groups (both 22 ng/ml). The galectin-1 level in the low CRF-high BMI group was significantly different from the other three groups (P<0.001). In conclusion, galectin-1 is associated with CRF as an indirect measure of the PA level through interconnection with body fatness. The size of the association is of clinical relevance.

Gendered relations? Associations between Swedish parents, siblings, and adolescents' time spent sedentary and physically active.

Introduction: The family is assumed to be fundamental in youth socialization processes and development, connected to social and cultural practices such as healthy lifestyles and physical activity. However, gender patterns in physical activity among adolescents and the structural drivers of gender inequality (e.g., parentage and siblingship) are poorly understood. The aim of this study was to explore further how gender structures relate to adolescents' time spent being sedentary and physically active, using contemporary gender theory. Methods: This cross-sectional study involved 1,139 adolescents aged 13-14 and their parents, including 815 mothers and 572 fathers. Physical activity and time spent sedentary were assessed through accelerometry among adolescents and through a self-report questionnaire for parents validated against accelerometry. Results: The results showed significant relationships between mothers' moderate-to-vigorous physical activity (MVPA) and girls' MVPA on weekdays and weekends, and fathers' MVPA was significantly related to girls' MVPA on weekdays. Our results imply that the relationship between Swedish parents' and adolescent girls' physical activity in higher intensities are to some extent gendered practices. However, time spent sedentary does not seem to show any patterns of being performed according to binary ideas of gender. Further, our exploratory analyses suggest that these results somewhat intersect with parents' educational level and relate to intra-categorical aspects of doing gender. The results also indicate slight gendered patterns in the "doing" of brotherhood for time spent sedentary, however, for boys only on weekends. Discussion: The study contributes to the understanding of gender norms as constraints and enablers for adolescents' participation in physical activity. The results can spur public health and physical activity research to apply a contemporary gender theory approach, and to expand the research agenda connected to what relates to gender inequalities in physical activity practices.

Accelerometer-based physical activity is associated with the gut microbiota in 8416 individuals in SCAPIS.

BACKGROUND: Previous population-based studies investigating the relationship between physical activity and the gut microbiota have relied on self-reported activity, prone to reporting bias. Here, we investigated the associations of accelerometer-based sedentary (SED), moderate-intensity (MPA), and vigorous-intensity (VPA) physical activity with the gut microbiota using cross-sectional data from the Swedish CArdioPulmonary bioImage Study. METHODS: In 8416 participants aged 50-65, time in SED, MPA, and VPA were estimated with hip-worn accelerometer. Gut microbiota was profiled using shotgun metagenomics of faecal samples. We applied multivariable regression models, adjusting for sociodemographic, lifestyle, and technical covariates, and accounted for multiple testing. FINDINGS: Overall, associations between time in SED and microbiota species abundance were in opposite direction to those for MPA or VPA. For example, MPA was associated with lower, while SED with higher abundance of Escherichia coli. MPA and VPA were associated with higher abundance of the butyrate-producers Faecalibacterium prausnitzii and Roseburia spp. We observed discrepancies between specific VPA and MPA associations, such as a positive association between MPA and Prevotella copri, while no association was detected for VPA. Additionally, SED, MPA and VPA were associated with the functional potential of the microbiome. For instance, MPA was associated with higher capacity for acetate synthesis and SED with lower carbohydrate degradation capacity. INTERPRETATION: Our findings suggest that sedentary and physical activity are associated with a similar set of gut microbiota species but in opposite directions. Furthermore, the intensity of physical activity may have specific effects on certain gut microbiota species. FUNDING: European Research Council, Swedish Heart-Lung Foundation, Swedish Research Council, Knut and Alice Wallenberg Foundation.

Cardiorespiratory fitness in midlife and subsequent incident depression, long-term sickness absence, and disability pension due to depression in 330,247 men and women.

OBJECTIVE: Specific information for whom and when cardiorespiratory fitness (CRF) is associated with depression risk is lacking. We aimed to study the association between adulthood CRF and incident depression, long-term sickness absence, and disability pension due to depression, as well as examine moderation of sex, age, education, and occupation on associations. METHODS: A large prospective cohort study follows participants over time with Swedish occupational health screenings data. The study includes 330,247 individuals (aged 16-79 years, 46% women) without a depression diagnosis at baseline. CRF was estimated from a submaximal cycle test. RESULTS: CRF was associated beneficially from low to higher levels with incident depression and long-term sickness absence due to depression. Further, CRF at high levels (≥46 ml/min/kg) was associated with a decreased risk of receiving disability pension due to depression. The associations remained after adjustment for age and sex, but not lifestyle-related factors and co-morbidity. Participants with moderate and high CRF had 16% and 21%, respectively, lower risk for incident depression, and participants with high CRF had 11% lower risk for long-term sickness absence due to depression. Associations between higher CRF and the outcomes were mainly evident in men, younger participants, and individuals with low education. CONCLUSION: In a large sample of adults without a depression diagnosis at baseline, higher CRF was shown to be beneficially related to the risk of incident depression and, to some extent, long-term sickness absence due to depression. If causal, targeted interventions focusing on increasing CRF in these sub-groups should be prioritized.

Improving movement behavior in office workers: effects of two multi-level cluster-RCT interventions on mental health.

BACKGROUND: We have previously reported on the design and efficacy of two cluster-randomized multi-level workplace interventions, attempting to decrease sedentary behavior (SED) or increase moderate to vigorous physical activity (MVPA) among office workers to improve mental health outcomes. The aim of this study was to investigate intervention effects on mental health outcomes, i.e., mental wellbeing, depression or anxiety symptoms, and stress immediately after the 6-month intervention period. METHODS: Teams of 263 office workers were cluster-randomized to one of two interventions or a waitlist control group. The PA intervention (iPA) focused on increasing MVPA and the SED intervention (iSED) on reducing SED. Both multi-level interventions targeted individual office workers and their social, physical, and organizational work environment, incorporating counseling based on cognitive behavioral therapy and motivational interviewing. Mental health outcomes were assessed using validated questionnaires before and immediately after the intervention. Intervention effects were analyzed using linear mixed effects models. RESULTS: Participants were mostly female and highly educated, with a mean age of 42 years and had favorable levels of mental health at baseline. Mental wellbeing improved for the iSED group (ß = 8, 95% CI 1 to 15, p = 0.030) but not for the iPA group (ß = 6, 95% CI -1 to 12, p = 0.072) compared to the control group. No effects were found for depression or anxiety symptoms or stress. CONCLUSIONS: The multi-level interventions improved mental wellbeing among this population of office workers, reaching statistical significance in the iSED group. The size of the effect can be regarded meaningful, considering favorable mental health and high PA level at baseline. Thus, workplace interventions that provide support on multiple levels appear to have potential for improving mental wellbeing, but not reducing ill-health variables, among healthy office workers. More research is needed to understand the mechanisms through which such improvements can be achieved and to identify the most effective intervention components. TRIAL REGISTRATION: ISRCTN92968402 (27 February 2018).

Eveningness is associated with coronary artery calcification in a middle-aged Swedish population.

Coronary artery calcification (CAC) is an established imaging biomarker of subclinical atherosclerosis, but its relationship to diurnal preference is not well studied. We investigated the association between chronotype and CAC in the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot cohort. Participants aged 50-64 years were randomly recruited and underwent extensive examination including imaging and accelerometry-assessed physical activity. 771 participants (47.3 % male, 57.6 ± 4.4 years) were included in this cross-sectional analysis. CAC was assessed by non-contrast computed tomography, and a CAC score > 10 was considered significant calcification. Self-assessed chronotype was classified as extreme morning, moderate morning, intermediate, moderate evening, or extreme evening. 10-year risk of first-onset cardiovascular disease was estimated by the Systemic Coronary Risk Evaluation 2 (SCORE2). Significant CAC was present in 29 % of the cohort. CAC prevalence increased from extreme morning to extreme evening type (22 %, 28 %, 29 %, 27 %, 41 % respectively, p = 0.018). In a multivariate logistic regression model controlling for confounders, extreme evening chronotype was independently associated with increased CAC prevalence compared to extreme morning type (OR 1.90, [95%CI 1.04-3.46], p = 0.037). When stratified by SCORE2 risk category (low: <5 %; moderate: 5 to <10 %; high: ≥10 %), significant CAC was most prevalent among extreme evening chronotypes in the low and moderate-risk groups, while chronotype seemed less important in the high-risk group (p = 0.011, p = 0.023, p = 0.86, respectively). Our findings suggest circadian factors may play an important role in atherosclerosis and should be considered in early cardiovascular prevention.

Accelerometer derived physical activity and subclinical coronary and carotid atherosclerosis: cross-sectional analyses in 22 703 middle-aged men and women in the SCAPIS study.

OBJECTIVES: The aim included investigation of the associations between sedentary (SED), low-intensity physical activity (LIPA), moderate-to-vigorous intensity PA (MVPA) and the prevalence of subclinical atherosclerosis in both coronaries and carotids and the estimated difference in prevalence by theoretical reallocation of time in different PA behaviours. DESIGN: Cross-sectional. SETTING: Multisite study at university hospitals. PARTICIPANTS: A total of 22 670 participants without cardiovascular disease (51% women, 57.4 years, SD 4.3) from the population-based Swedish CArdioPulmonary bioImage study were included. SED, LIPA and MVPA were assessed by hip-worn accelerometer. PRIMARY AND SECONDARY OUTCOMES: Any and significant subclinical coronary atherosclerosis (CA), Coronary Artery Calcium Score (CACS) and carotid atherosclerosis (CarA) were derived from imaging data from coronary CT angiography and carotid ultrasound. RESULTS: High daily SED (>70% ≈10.5 hours/day) associated with a higher OR 1.44 (95% CI 1.09 to 1.91), for significant CA, and with lower OR 0.77 (95% CI 0.63 to 0.95), for significant CarA. High LIPA (>55% ≈8 hours/day) associated with lower OR for significant CA 0.70 (95% CI 0.51 to 0.96), and CACS, 0.71 (95% CI 0.51 to 0.97), but with higher OR for CarA 1.41 (95% CI 1.12 to 1.76). MVPA above reference level, >2% ≈20 min/day, associated with lower OR for significant CA (OR range 0.61-0.67), CACS (OR range 0.71-0.75) and CarA (OR range 0.72-0.79). Theoretical replacement of 30 min of SED into an equal amount of MVPA associated with lower OR for significant CA, especially in participants with high SED 0.84 (95% CI 0.76 to 0.96) or low MVPA 0.51 (0.36 to 0.73). CONCLUSIONS: MVPA was associated with a lower risk for significant atherosclerosis in both coronaries and carotids, while the association varied in strength and direction for SED and LIPA, respectively. If causal, clinical implications include avoiding high levels of daily SED and low levels of MVPA to reduce the risk of developing significant subclinical atherosclerosis.

Accelerometer-measured absolute versus relative physical activity intensity: cross-sectional associations with cardiometabolic health in midlife.

BACKGROUND: Observational studies investigating the association between accelerometer-measured physical activity and health all use absolute measures of physical activity intensity. However, intervention studies suggest that the physical activity intensity required to improve health is relative to individual fitness. The aim of this study was to investigate the associations between accelerometer-measured absolute and relative physical activity intensity and cardiometabolic health, and what implications these associations may have on the interpretation of health-associated physical activity. METHODS: A sample of the cross-sectional Swedish CArdioPulmonary bioImage Study (SCAPIS) consisting of 4,234 men and women aged 55-64 years was studied. Physical activity intensity was measured by accelerometry and expressed as absolute (e.g., metabolic equivalents of task) or relative (percentage of maximal oxygen consumption). Fitness was estimated by the submaximal Ekblom-Bak test. A composite ('metabolic syndrome') score combined measures of waist circumference, systolic blood pressure, high-density lipoprotein, triglycerides, and glycated hemoglobin. Associations of absolute and relative physical activity intensity with the health indicators (i.e., fitness and metabolic syndrome score) were studied by partial least squares regression. Analyses were stratified by fitness level. RESULTS: Both absolute and relative physical activity intensity associated with the health indicators. However, the strongest associations for absolute intensity varied depending on fitness levels, whereas the associations for relative intensity were more synchronized across fitness groups. The dose-response relationship between moderate-to-vigorous intensity and the health indicators was stronger for relative than for absolute intensity. The absolute and relative moderate-to-vigorous intensity cut-offs intersected at the 5th fitness percentile, indicating that the absolute intensity cut-off is too low for 95% of individuals in this sample. While 99% of individuals fulfilled the general physical activity recommendations based on absolute intensity measures, only 21% fulfilled the recommendations based on relative intensity measures. In relation to a "sufficient" fitness level, 9% fulfilled the recommendations. CONCLUSIONS: Accelerometer-measured relative physical activity intensity represents the intensity related to health benefits regardless of fitness level. Traditional absolute moderate intensity accelerometer cut-offs are too low for most individuals and should be adapted to the fitness level in the sample studied. Absolute and relative physical activity intensity cannot be used interchangeably.

Changes in Physical Activity and Incidence of Nonfatal Cardiovascular Events in 47 153 Survivors of Myocardial Infarction.

Background The majority of patients survive the acute phase of myocardial infarction (MI) but have an increased risk of recurrent cardiovascular disease (CVD) events. To be regularly physically active or change activity level is associated with a lower risk of all-cause mortality. The objective was to explore to what extent physical activity (PA) levels or change in PA levels during the first year post-MI was associated with any recurrent nonfatal CVD events and specific CVD events (eg, MI, ischemic stroke, and vascular dementia). Methods and Results This cohort study among MI survivors was based on Swedish national registries between 2005 and 2020. PA levels were self-rated at 2 and 12 months post-MI, and patients were classified into remaining physically inactive, increasing, decreasing, or remaining active. A total of 6534 nonfatal CVD events occurred during 6 years of follow-up among the 47 153 included patients. In fully adjusted analyses, the risk of any nonfatal CVD event was lower (P<0.05) among patients remaining active (37%), increasing (22%), or decreasing (18%) PA level compared with remaining inactive. Compared with remaining inactive, the risk of recurring MI and stroke was lower (P>0.05) among remaining active (41% versus 52%, respectively), increasing (20% versus 35%, respectively), or decreasing PA level (24% versus 34%, respectively). For vascular dementia, patients remaining physically active had an 80% lower risk compared with remaining inactive (P<0.05). Conclusions Remaining physically active or change in PA levels during the first year post-MI was associated with a lower risk of recurrent nonfatal CVD events. This emphasizes the importance of supporting patients to continue to be or become physically active.

Associations between physical activity and autonomic function during deep breathing test: the Swedish CArdioPulmonary bioImage Study (SCAPIS).

PURPOSE: The deep breathing test (DBT) is a sensitive test of cardiovagal function. The aim of this study was to explore associations between physical activity and sedentary time, measured by accelerometer, and autonomic function, using DBT. METHODS: In the Swedish Cardio-Pulmonary bioImage Study, men and women aged 50-64 were randomly invited from the general population. A total of 4325 subjects who underwent DBT and assessment of physical activity and sedentary time by accelerometery were included. ECG files from 1-min DBT were used to calculate measures of respiratory sinus arrhythmia [RSA; expiration-inspiration (E-I) difference and E/I ratio], heart rate variability [HRV; root mean square of successive differences (RMSSD), standard deviation of heart rates and mean circular resultant]. Low RSA and HRV was defined as the lowest 10% in the population. RESULTS: For accelerometer-assessed physical activity, there were significant associations between high percentage of sedentary time and low E/I (p < 0.01), and low RMSSD (p < 0.01) in an age- and sex-adjusted model, and between percentage of sedentary time and low RMSSD (p = 0.04) in a risk factor-adjusted model. Low RMSSD was less common in those with a high percentage of moderate to vigorous physical activity (p = 0.04, after risk-factor adjustment). These associations became non-significant when further adjusting for heart rate. CONCLUSION: We report associations between degree of physical activity and indices of autonomic dysfunction in a large population. The relationships were no longer significant after adjustments for heart rate, indicating that the relationship between physical activity and cardiovagal function partly is accounted for by reduced heart rate.

Acute effects of nitrate and breakfast on working memory, cerebral blood flow, arterial stiffness, and psychological factors in adolescents: Study protocol for a randomised crossover trial.

BACKGROUND: Inorganic nitrate has been shown to acutely improve working memory in adults, potentially by altering cerebral and peripheral vasculature. However, this remains unknown in adolescents. Furthermore, breakfast is important for overall health and psychological well-being. Therefore, this study will investigate the acute effects of nitrate and breakfast on working memory performance, task-related cerebral blood flow (CBF), arterial stiffness, and psychological outcomes in Swedish adolescents. METHODS: This randomised crossover trial will recruit at least 43 adolescents (13-15 years old). There will be three experimental breakfast conditions: (1) none, (2) low-nitrate (normal breakfast), and (3) high-nitrate (concentrated beetroot juice with normal breakfast). Working memory (n-back tests), CBF (task-related changes in oxygenated and deoxygenated haemoglobin in the prefrontal cortex), and arterial stiffness (pulse wave velocity and augmentation index) will be measured twice, immediately after breakfast and 130 min later. Measures of psychological factors and salivary nitrate/nitrite will be assessed once before the conditions and at two-time points after the conditions. DISCUSSION: This study will provide insight into the acute effects of nitrate and breakfast on working memory in adolescents and to what extent any such effects can be explained by changes in CBF. This study will also shed light upon whether oral intake of nitrate may acutely improve arterial stiffness and psychological well-being, in adolescents. Consequently, results will indicate if nitrate intake from beetroot juice or if breakfast itself could acutely improve cognitive, vascular, and psychological health in adolescents, which can affect academic performance and have implications for policies regarding school meals. TRIAL REGISTRATION: The trial has been prospectively registered on 21/02/2022 at https://doi.org/10.1186/ISRCTN16596056. Trial number: ISRCTN16596056.

COVID-19 and unfavorable changes in mental health unrelated to changes in physical activity, sedentary time, and health behaviors among Swedish adolescents: A longitudinal study.

Background: The COVID-19 pandemic has had major impact on the daily lives of adolescents. This study examined whether mental health outcomes had changed over the pandemic, and if such changes were related to changes in physical activity (PA), sedentary time, sleep, screen time, and participation in organized sports. Materials and methods: In this longitudinal study, data were collected in autumn 2019 with follow-up measurements in spring 2021. In total, 558 schools were invited and 34 schools around Stockholm with a variation in socioeconomic background were included. Physical activity and sedentary time were measured for seven consecutive days by accelerometry (Actigraph). Anxiety, health-related quality of life (HRQoL), psychosomatic health, stress, sleep duration, screen time, and organized sports participation were self-reported in questionnaires. Linear models were applied to estimate associations between changes in mental health outcomes and exposures. Results: From the baseline sample of 1,139 participants, 585 (55% girls), mean (SD) age 14.9 (0.3) years, participated in the follow-up. Between 2019 and 2021, there was a decrease in HRQoL [mean difference -1.7 (-2.3, -1.2), p < 0.001], increase in psychosomatic health problems [mean difference 1.8 (1.3, 2.3), p < 0.001], and an increase in the number of participants with high stress [from 94 (28%) to 139 (42%), p < 0.001]. Weekly light PA and sleep duration decreased and weekly sedentary time and screen time increased unrelated to changes in mental health outcomes. An increase in sleep duration during weekdays was significantly related to both a decrease in anxiety (B = -0.71, CI: -1.36, -0.06) and an increase in HRQoL (B = 1.00, CI: 0.51, 1.49). Conclusion: During the COVID-19 pandemic, mental health appears to have been impaired in Swedish adolescents, but unrelated to changes in PA, sedentary time, screen time, or participation in organized sports. However, increased sleep duration on weekdays was related to less anxiety and better HRQoL. The results may help policy makers and other stakeholders comprehend the differential effects of the COVID-19 pandemic on mental health outcomes and help guiding the planning of policy actions. Trial registration: ISRCTN15689873.

Effects of prolonged sitting and physical activity breaks on measures of arterial stiffness and cortisol in adolescents.

AIM: In adults, prolonged periods of sitting have been linked to acute negative effects on vascular structure and function. The aim of this study was to evaluate the acute effects of physical activity (PA) breaks during prolonged sitting on arterial stiffness, cortisol and psychological factors in adolescents. METHODS: Adolescents underwent different short (3-min) breaks starting every 20 min, during 80 min of sitting on three separate days. Breaks were (A) social seated breaks (SOC), (B) low-intensity simple resistance activity PA breaks (SRA) and (C) moderate-intensity step-up PA breaks (STEP). The arterial stiffness measures were augmentation index (AIx), AIx@75 and pulse wave velocity (PWV). Cortisol was measured from saliva. Psychological factors were self-reported. RESULTS: Eleven girls and six boys (average age 13.6 ± 0.7 years) participated, with average baseline heart rates of 72 ± 11 bpm, systolic/diastolic blood pressure 111 ± 7/64 ± 6 mmHg and cortisol 10.9 ± 5.8 nmoL/L. PWV, cortisol and psychological factors did not change after any of the conditions. AIx@75 increased significantly (4.9 ± 8.7-9.2 ± 13.2) after the STEP intervention compared with SOC and SRA (time × condition p < 0.05). CONCLUSION: Arterial stiffness increased after prolonged sitting with frequent, short step-up activity breaks. The results indicate potential important intensity-dependent effects of physical activity on vascular regulation in youth.

COVID-19 induced changes in physical activity patterns, screen time and sleep among Swedish adolescents - a cohort study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic had a huge impact on daily life, even in countries such as Sweden where the restrictions were relatively mild. This paper assesses the effects of the COVID-19 pandemic restrictions on physical activity (PA) patterns, screen time, and sleep among Swedish adolescents. The exposures explored include gender, parental education, anthropometrics, and cardiovascular fitness (CVF). METHODS: Cohort data were collected from September 26th to December 6th, 2019, and from April 12th to June 9th, 2021. Participants were 13-14 years-old (7th graders) at baseline with 585 participating at both baseline and follow-up. At both baseline and follow-up PA and sedentary time were measured with accelerometers, and sleep and screen time with questionnaires. The exposure variables (gender, parental education, anthropometrics and CVF) were collected at baseline. Multilevel linear regression analyses were performed. RESULTS: Moderate-to-vigorous-physical activity (MVPA) remained unchanged while light physical activity (LiPA) decreased and sedentary time increased. Sleep duration decreased and screen time increased. Girls, adolescents with overweight/obesity (BMI and percent body fat), and those with lower CVF at baseline had less favourable changes in PA patterns, sleep and screen time. CONCLUSIONS: Although no significant (α = 0.05) changes were seen in MVPA, both LiPA and sedentary time as well as sleep and screen time changed in unfavourable ways. More intense activities are often organised and seem to have withstood the pandemic, while less intense activities decreased. Some groups were more vulnerable and will need directed intervention in the post-pandemic period as well as when future pandemics hit.

Correlates of cardiorespiratory fitness in a population-based sample of middle-aged adults: cross-sectional analyses in the SCAPIS study.

OBJECTIVES: This study aimed to identify main sex-specific correlates of cardiorespiratory fitness (CRF) in a population-based, urban sample of Swedish adults. DESIGN: Cross-sectional. SETTING: Multi-site study at university hospitals, data from the Gothenburg site. PARTICIPANTS: A total of 5308 participants (51% women, aged 50-64 years) with a valid estimated VO2max, from submaximal cycle test, in the Swedish CArdioPulmonary bioImage Study (SCAPIS), were included. PRIMARY AND SECONDARY OUTCOMES: A wide range of correlates were examined including (a) sociodemographic and lifestyle behaviours, (b) perceived health, anthropometrics and chronic conditions and (c) self-reported as well as accelerometer-derived physical activity and sedentary behaviours. Both continuous levels of estimated VO2max as well as odds ratios (OR) and confidence intervals (CI)s of low VO2max (lowest sex-specific tertile) were reported. RESULTS: In multivariable regression analyses, higher age, being born abroad, short education, high waist circumference, poor perceived health, high accelerometer-derived time in sedentary and low in vigorous physical activity, as well as being passive commuter, correlated independently and significantly with low VO2max in both men and women (OR range 1.31-9.58). Additionally in men, financial strain and being an ex-smoker are associated with higher odds for low VO2max (OR 2.15; 95% CI 1.33 to 3.48 and OR 1.40; 95% CI 1.09 to 1.80), while constant stress with lower odds (OR 0.61; 95% CI 0.43 to 0.85). Additionally in women, being a regular smoker is associated with lower odds for low VO2max (OR 0.64; 95% CI 0.45 to 0.92). CONCLUSIONS: The present study provides important reference material on CRF and correlates of CRF in a general middle-aged population, which can be valuable for future research, clinical practice and public health work. If relations are causal, increased knowledge about specific subgroups will aid in the development of appropriate, targeted interventions.

The interrelationship between physical activity intensity, cardiorespiratory fitness, and executive function in middle-aged adults: An observational study of office workers.

Background: Previous evidence supports a beneficial effect of physical activity on executive function across the whole lifespan. Yet, the interrelationships of the intensities of physical activity, cardiorespiratory fitness, and executive function require further investigation in adults. Aim: Using unfiltered accelerometry data and high-resolution intensity classification, we sought to estimate the associations of physical activity with cardiorespiratory fitness and executive function in adult office workers. Methods: We included 343 full-time office workers (mean age: 42.41 years, range of age: 36-49 years). Executive function was assessed using Stroop, Trail making tests (part-B), and 2-back tests, and a composite score was produced to reflect the general executive function performance. Physical activity was assessed using the Actigraph GT3X+-monitor, worn by each participant for seven days at the hip. Raw accelerometry data were processed by the 10 Hz frequency extended method and divided into 22 intensity bins and sleep time. Cardiorespiratory fitness was estimated using the submaximal Ekblom-Bak cycle ergometer test. Data were analyzed using partial least squares regressions. Results: In adults, cardiorespiratory fitness was closely correlated with a wide range of absolute physical activity intensity patterns. A higher level of executive function in adults was associated with both higher absolute physical activity intensities and cardiorespiratory fitness, which was independent of age, sex, and education levels. A very weak association between intensities, fitness, and executive function was observed in high-fit adults. Among low-fit adults, although a positive association started already toward the upper end of moderate intensity, there still appeared to be an association between intensities, cardiorespiratory fitness, and executive function. That is, cardiorespiratory fitness may mediate the association between absolute physical activity intensities and executive function up to a certain level. Conclusion: The maintenance of executive function in adulthood was related to both physical activity intensities and cardiorespiratory fitness, while their interrelationship was not equal across fitness levels. It is highly recommended to consider the cardiorespiratory fitness level in future studies that focus on executive functions in aging as well when designing individualized physical activity training programs.