Physical activity and health outcomes

Background: Previous studies have calculated preventable deaths using self-report physical activity (PA) data to estimate the effects of participants changing from not meeting to meeting the current PA recommendations. This approach may not be feasible for all individuals and fails to capture improvements at the lower end of moderate-to-vigorous-intensity (MVPA) distribution. Purpose: To estimate the proportion of preventable deaths associated with realistically increases in MVPA and reductions in sedentary time while accounting for the non-linear, dose-response associations between these exposures and risk for mortality. Methods: Individual participant data meta-analysis of seven prospective cohorts from Norway, Sweden, and the US (N=40,327; 4895 deaths) with device-measured physical activity and sedentary time. The potential impact fraction was calculated from adjusted hazard ratios estimated for five min increases in MVPA and 30 min reductions in sedentary time from observed levels across the activity distribution. Results: A five-minute increase in MVPA per day in the least active ~20% of participants may prevent 6.0% (95% CI: 4.3%-7.4%) of all deaths. A similar increase in MVPA in the bottom ~80% participants (excluding the most active 20%) may prevent 10.0% (95% CI 6.3% to 13.4%) of all deaths. Reducing sedentary time by 30 minutes per day may prevent 3.0% (2.0% to 4.1%) and 7.3% (4.8% to 9.6%) of all deaths in the two groups, respectively Conclusion: Small and realistically achievable increases in MVPA of five minutes per day may prevent up to 6% and 10% of all deaths when targeted in a ‘high-risk’ and a ‘population’ approach, respectively. Reducing sedentary time by 30 min per day prevented a smaller proportion of deaths in two risk scenarios, respectively. Practical implications: Public health professionals and practitioners should consider promoting small increases in daily MVPA especially in the least active proportion of the population. Funding: NA

Background. Sedentary time and physical inactivity increase the risk of unhealthy weight and are negatively associated with children’s motor competence development. Children with healthy weight and motor skill proficiency are more predisposed to adopt physically active lifestyles as they progress into adolescence. Schools are important settings for physical activity participation, but little is known about the optimum combinations of movement behaviours during the school day for physical health and development.

Purpose. To describe the Goldilocks (‘just right’) school day movement behaviour compositions for physical health and development, and to specify the time-use composition that optimised both healthy weight and motor competency as physical health and development outcomes.

Methods. Children from seven northwest England primary-schools (n=177, 55% girls, 78% White British, age=8.60.4-years) completed anthropometric assessments, wore a wrist accelerometer for 24 hoursday-1 over 7-days, and completed the Dragon Challenge motor competence assessment. Accelerometer cut-points were applied to estimate school-day time spent being sedentary (ST) and in light (LPA), moderate (MPA), and vigorous physical activity (VPA). BMI-z scores represented the physical health outcome, and total motor competence scores represented the physical development outcome. Associations between school-day movement behaviour compositions and the two outcomes were analysed separately using compositional regression. The compositional centres of the optimal BMI-z and motor competence compositions were calculated to reflect the optimal Goldilocks school-day composition for physical health and development.

Results. The mean school-day movement behaviours composition (ST=264-min, LPA=95-min, MPA=24.0-min, VPA=7-min) was significantly associated with BMI z-score (p=0.03) and motor competence (p=0.01). Optimal durations of school-day movement behaviour compositions varied for BMI-z score and motor competence. The overall Goldilocks school-day to optimise physical health and development comprised 232-min of ST, 130-min of LPA, 11-min of MPA, and 17-min of VPA.

Conclusions. The optimal composition approach can provide physical health- and development-related movement goals for whole-school physical activity promotion.

Background: The health outcomes of long-term patterns of meeting physical activity (PA) guidelines in women have seldom been explored. Purpose: To examine the associations between longitudinal patterns of PA over 15 years and all-cause and cause-specific mortality in a cohort of mid-aged Australian women. Methods: We analysed data collected at 3-year intervals from 11,336 participants in the Australian Longitudinal Study on Women’s Health (ALSWH; 1946-51 cohort). Mortality outcomes (all-cause, cardiovascular disease, cancer) were derived from Australian death registries. We analysed associations between meeting the WHO PA guidelines (150 min/week of moderate-to-vigorous PA) in 2001-2016 and outcomes in 2019. Using causal inference modelling, we emulated a target trial testing two interventions: 1) meeting the guidelines throughout the ‘exposure period’ (2001-2016) and 2) not meeting the guidelines at the beginning of the exposure period, but starting to first meet the guidelines at age 55, 60, and 65. Both were compared to the control of not meeting the guidelines throughout the exposure period. Analyses were adjusted for sociodemographic and health variables using marginal structural models. Results: Consistent adherence to PA guidelines throughout the exposure period was significantly associated with a ~5% lower risk of all-cause mortality (incidence risk: 5.2% [95% CI: 3.3%, 7.2%]) than the control (10.4% [5.4%, 15.4%]). No significant associations were found for cause-specific mortality. Starting to meet guidelines at age 55, 60 and 65 were not significantly associated with all-cause/cause-specific mortality, compared with control. Conclusions: Mid-aged women should maintain PA for health benefits. Practical implications: An important public health message is that women can gain important health benefits from staying active in mid-age. Funding: The ALSWH is funded by the Australian Government Department of Health. GIM: National Health and Medical Research Council (NHMRC) Investigator Grant (APP2008702). DD: NHMRC Emerging Leader Fellowship (2009254); NSW Cardiovascular Research Capacity Program EMCR Grant.

Background: Sleep, physical activity, and nutrition (SPAN) are critical behaviours for health, although they have traditionally been studied separately.

Purpose: To examine the combined associations of SPAN and establish the minimum variations needed to meaningfully reduce all-cause mortality risk.

Methods: This was a prospective cohort analysis of 59,078 participants from the UK Biobank (median age: 64.0 years; 45.4% male) who wore trackers for 7 days and self-reported dietary data. Wearable-measured sleep duration (hours/day) and moderate to vigorous physical activity duration (MVPA; mins/day) were calculated using a machine learning based schema. A 10-item diet quality score (DQS) assessed the intake of vegetables, fruits, fish, dairy, whole grains, vegetable oils, refined grains, processed and unprocessed meats, and sugary beverages (range 0-100 for all components with higher values indicating higher quality). Cox proportional hazards models were used to estimate hazard ratios (HR) for all-cause mortality risk across 27 separate joint tertile combinations of SPAN behaviours.

Results: Compared to the referent group of combined SPAN exposure (lowest tertiles for all three), the optimal SPAN combination involving moderate sleep duration (7.2-8.0 hours/day), high MVPA (42-103 mins/day), and a DQS between 57.5 and 72.5 was associated with an HR of 0.36 (95% CI: 0.26-0.50). Relative to the 5th percentile of sleep (5.5 hours/day), MVPA (7.3 mins/day), and nutrition (36.9 DQS), a minimum increase of 15 mins/day of sleep, 1.6 min/day MVPA, and 5 DQS points was associated with a 10% reduction in all-cause mortality risk (0.90; 0.88-0.93). An additional 75 mins/day of sleep, 12.5 min/day MVPA, and 25 DQS points were associated with a 50% reduction in all-cause mortality risk (0.50; 0.44-0.58).

Conclusions: This study highlights the potential health value of subtle combined lifestyle modification for reducing mortality risk.

Practical implications: These results expand feasible options for more holistic lifestyle recommendations.

Funding: NHMRC Investigator Grant (APP1194510).

Background: The global pandemic of paediatric obesity, physical inactivity and unhealthy diets are important future health challenges. Purpose: To determine 4-year changes in physical activity (PA) and food selection, and the association with adiposity among South African children. Methods: School children aged 5 to 9 years old in 2017 (n=920) were followed up four years later (2021-2022). PA was determined by accelerometry (Actigraph). Parents indicated selection from healthy and unhealthy food groups in a validated questionnaire. Weight and height of the children were measured, and WHO BMI z-score (BAZ) was calculated. Percentage body fat (%BF) was determined using bio-electric impedance analysis. Changes in PA, frequency of food selection, BAZ and %BF from baseline to end were assessed. Associations between PA and BAZ at baseline and end, and the association between PA, frequency of food selection, age, and household income with 4-year change in BAZ was determined. Results: Moderate and vigorous PA (MVPA) decreased over four years, while sedentary time and BAZ increased (all P<0.001). MVPA correlated negatively with BAZ and %BF. The frequency of selection from most food groups remained unchanged. The frequency of sugar-sweetened beverages intake decreased, while the intake from fast-foods showed a trend of an increase. Food selection variables showed no association with the increase in BAZ. In a regression model trends of negative associations were found between age (ß= -0.16, p=0.058) and MVPA (ß= -0.15, p=0.07), respectively, with 4-year change in BAZ. Conclusions: PA showed a stronger association with increasing adiposity among school children, than socio-demographic variables or food selection. Practical implications: The declining PA of school children in South Africa needs to be addressed. Policies to control food marketing and sugar-sweetened beverages sales are in place, but none to promote PA. Funding: South African Medical Research Council and National Research Foundation of South Africa.

Background: In 2023, exactly 100 years have passed since the first nationwide testing of the physical fitness level among youth in the territory of the former Czechoslovakia. Purpose: As part of this unique and unrepeatable opportunity, the main aim of the study was to conduct repeated cross-sectional research based on historical methodology and to compare objectively measured physical fitness data in 11–19-year-old children and adolescents from Central Europe between 1923 and 2023. Methods: The research was carried out according to contemporary methodology from 1923. The repeated cross-sectional research in 2023 included a sample of 4,741boys and girls selected from 15 Czech and 5 Slovak schools. Research methods included both somatic measurements (body height, sitting height, and body weight) and motor tests (standing broad jump, standing small ball throw, pull-ups, speed running, and endurance running). Results: All somatic characteristics increased after 100 years. For example, the average increase in body height is 9.8 cm for 18-year-old boys and 9.6 cm for girls of the same age. The average increase in body weight is 11.6 kg for boys and 7.1 kg for girls. The development in motor performance is inconsistent. Compared to historical data, current results are significantly better in standing broad jump or speed running and worse in standing small ball throw or pull-ups. In endurance running, values differ according to age category (younger children have today better results than 100 years ago, older adolescents vice versa). Conclusions: The findings showed an increase in all somatic characteristics in Central European children and adolescents after 100 years, most progressively in body weight. Motor performance is generally at a similar level. Practical implications: Long-term monitoring of physical fitness is an important indicator of health in the pediatric population. Funding: This study was supported by the research grant of Technical University of Liberec (SGS-2023-4397).