Assessment of an intervention for preventing pediatric overweight and obesity through the World Café technique: A qualitative study.

PURPOSE: To evaluate the self-reported perspectives of participants involved in the Previene Cádiz intervention for preventing pediatric overweight and obesity. DESIGN AND METHODS: This qualitative study collected information through the World Café technique. A purposive sample of 40 participants was used, of which 14 were schoolchildren, 12 were teachers, and 14 were parent volunteers. The data were segmented, and concepts were created and grouped into dimensions and categories. RESULTS: The participants confirmed they had learned new information and behaviors about healthy habits. Parental awareness was considered a crucial and necessary element in changing family habits; therefore, increasing the motivation of family members was deemed a critical task in public health interventions conducted in school settings. DISCUSSION: Despite the suitability of qualitative methodology to evaluate the perceptions of the main players in an educational intervention, scientific literature is scarce. Obtaining information from the educational community about an intervention is not always easy, so the perspectives of teachers, students, and families about the Previene Cádiz intervention through the World Café approach is considered a relevant contribution. CONCLUSIONS: The participants considered the intervention positive in terms of learning and fostering increased knowledge, awareness, and healthy behaviors. PRACTICE IMPLICATIONS: Future interventions should encourage the active participation of all social groups involved, integrating dynamic and collaborative training activities that are acceptable to all participants.

Role of physical activity and health-related fitness on self-confidence and interpersonal relations in 14-year-old adolescents from secondary school settings: DADOS study.

BACKGROUND: The effect of physical activity (PA) and physical fitness (PF) on self-confidence and interpersonal relations in adolescents is uncertain. AIM: To analyzed the associations of PA and PF with self-confidence and interpersonal relations in adolescents. SAMPLE: A total of 268 (138 boys) adolescents (13.9 ± 0.3 years) from the DADOS study were included in the analysis. METHODS: PA was evaluated using GENEActiv accelerometers and the health-related PF components by the ALPHA health-related fitness test battery. The levels of self-confidence and interpersonal relations were determined by the Behavior Assessment System for Children Level 3. RESULTS: The associations of PA levels and PF components with self-confidence reported positive associations of moderate-vigorous PA (MVPA), standing long jump, and 20-m shuttle run (shuttle run test) tests (all p < 0.05), and negative association of 4 × 10-m shuttle run test (4 × 10-m test), but only the 4 × 10-m test remained significant in the adjusted model for the whole sample and only in boys (p ≤ 0.01) when analyzed by sex. Regarding interpersonal relations, positive associations of standing long jump and shuttle run test (all p < 0.05), and negative association of 4 × 10-m test were found in all the adolescents. The shuttle run test was associated with interpersonal relations in boys independently of confounders. PA levels were not associated with interpersonal relations. CONCLUSION: A higher level of lower-limb muscle strength, speed-agility, and cardiorespiratory fitness might improve self-confidence and interpersonal relations in adolescents, but these relationships seem to be influenced by sex, body mass index, and pubertal status. Speed-agility and cardiorespiratory fitness seem to have a stronger impact on boys. MVPA may improve self-confidence in adolescents.

Thermal resting pattern and acute skin temperature response to exercise in older adults: Role of cardiorespiratory fitness.

BACKGROUND: Infrared thermography is a growing area of interest in sports science due to the potential of skin temperature (Tsk) measurements to provide valuable information from rest to exercise. However, limited research exists on Tsk in older adults and the impact of factors such as sex and cardiorespiratory fitness (CRF) on Tsk. This study aims to investigate Tsk at rest and after acute exercise in older adults and assess whether sex or CRF influences Tsk. METHODS: Ninety-two participants (41 women, 68.48 ± 3.01 years) were examined with a thermographic camera in a conditioned room (23.02 ± 3.01 °C) at rest and after a graded protocol. The Tsk of 25 regions of interest (ROIs) were extracted and analysed. RESULTS: Men had higher overall Tsk at rest in 76% of ROIs, showing significant differences (p < 0.010) in six specific ROIs, independent of CRF. Both sexes had similar Tsk responses after graded exercise, with increases in distal parts (1.06 ± 0.50 °C), decreases in proximal parts (-0.62 ± 0.42 °C), and stable central Tsk (0.23 ± 0.59 °C). Increases in lower limb Tsk were significantly associated with CRF in men and women (ß = 0.438, p = 0.001, and ß = 0.535, p < 0.001, respectively), explaining 17% and 27% of the variance, respectively. CONCLUSIONS: This study demonstrates a sex-specific effect on resting Tsk in older adults, suggesting that sex-specific Tsk patterns should be considered when analysing Tsk in this population. Additionally, the association between increases in lower limb Tsk and CRF suggests that Tsk could be a promising predictor of CRF in older adults.

Train at home, but not alone: a randomised controlled multicentre trial assessing the effects of live-streamed tele-exercise during COVID-19-related lockdowns.

OBJECTIVE: Public life restrictions associated with the COVID-19 pandemic caused reductions in physical activity (PA) and decreases in mental and somatic health. Considering the interplay between these factors, we investigated the effects of digital home exercise (DHE) during government-enforced lockdowns. METHODS: A multicentre randomised controlled trial was performed allocating healthy individuals from nine countries (N=763; 523 female) to a DHE or an inactive control group. During the 4-week main intervention, DHE members engaged in live-streamed multicomponent home exercise. Subsequently, both groups had access to prerecorded workouts for an additional 4 weeks. Outcomes, assessed weekly, included PA level (Nordic Physical Activity Questionnaire-Short), anxiety (Generalized Anxiety Disorder Scale-7), mental well-being (WHO-5 Questionnaire), sleep quality (Medical Outcome Study Sleep Scale), pain/disability (Chronic Pain Grade Scale) and exercise motivation (Self-Concordance Scale). Mixed models were used for analysis. RESULTS: Live-streamed DHE consistently increased moderate PA (eg, week 1: 1.65 times more minutes per week, 95% CI 1.40 to 1.94) and vigorous PA (eg, week 1: 1.31 times more minutes per week, 95% CI 1.08 to 1.61), although the effects decreased over time. In addition, exercise motivation, sleep quality and anxiety were slightly improved for DHE in the 4-week live streaming period. The same applied to mental well-being (mean difference at week 4: +0.99, 95% CI 0.13 to 1.86), but an inverted trend was observed after live streaming was substituted by prerecorded exercise. CONCLUSIONS: Live-streamed DHE represents an efficacious method to enhance PA and selected markers of health during pandemic-related public life restrictions. However, research on implementation is warranted to reduce dropout rates. TRIAL REGISTRATION NUMBER: DRKS00021273.

Effects of exercise on exosome release and cargo in in vivo and ex vivo models: A systematic review.

Exercise-released exosomes have been identified as novel players to mediate cell-to-cell communication in promoting systemic beneficial effects. This review aimed to systematically investigate the effects of exercise on exosome release and cargo, as well as provide an overview of their physiological implications. Among the 436 articles obtained in the database search (WOS, Scopus, and PubMed), 19 articles were included based on eligibility criteria. Results indicate that exercise promotes the release of exosomes without modification of its vesicle size. The literature has primarily shown an exercise-driven increase in exosome markers (Alix, CD63, CD81, and Flot-1), along with other exosome-carried proteins, into circulation. However, exosome isolation, characterization, and phenotyping methodology, as well as timing of sample recovery following exercise can influence the analysis and interpretation of findings. Moreover, a large number of exosome-carried microRNAs (miRNAs), including miR-1, miR-133a, miR-133b, miR-206, and miR-486, in response to exercise are involved in the modulation of proliferation and differentiation of skeletal muscle tissue, although antigen-presenting cells, leukocytes, endothelial cells, and platelets are the main sources of exosome release into the circulation. Collectively, with the physiological implications as evidenced by the ex vivo trials, the release of exercise-promoted exosomes and their cargo could provide the potential therapeutic applications via the role of intercellular communication.

Impact of an intermittent and localized cooling intervention on skin temperature, sleep quality and energy expenditure in free-living, young, healthy adults.

Where people live and work together it is not always possible to modify the ambient temperature; ways must therefore be found that allow individuals to feel thermally comfortable in such settings. The Embr Wave® is a wrist-worn device marketed as a 'personal thermostat' that can apply a local cooling stimulus to the skin. The aim of the present study was to determine the effect of an intermittent mild cold stimulus of 25 °C for 15-20 s every 5 min over 3.5 days under free-living conditions on 1) skin temperature, 2) perception of skin temperature, 3) sleep quality and 4) resting energy expenditure (REE) in young, healthy adults. Ten subjects wore the device for 3.5 consecutive days. This intervention reduced distal skin temperature after correcting for personal ambient temperature (P < 0.05), but did not affect the subjects' the perception of skin temperature, sleep quality or REE (all P ≥ 0.051). Thus, this intermittent mild cold regime can reduce distal skin temperature, and wearing it under free-living conditions for 3.5 days does not seem to impair the perception of skin temperature and sleep quality or modify REE.

Evidence of high 18 F-fluorodeoxyglucose uptake in the subcutaneous adipose tissue of the dorsocervical area in young adults.

NEW FINDINGS: What is the central question of this study? In some studies, biopsies have been performed of the subcutaneous adipose tissue in the abdomen, and they failed to find browning markers. Is the abdomen the right place to take biopsies? What is the main finding and its importance? For first time, we observed that the glucose uptake in the dorsocervical subcutaneous adipose tissue is higher in comparison to other areas of subcutaneous adipose tissue. ABSTRACT: Neonates have subcutaneous brown adipose tissue (BAT) in the dorsocervical area, and it is thought that these depots gradually disappear with age. Here, we determined that young adults have high 18 F-flurodeoxyglucose (18 F-FDG) uptake in the subcutaneous adipose tissue (SAT) of the dorsocervical area. A total of 133 young adults (age 22 ± 2 years; body mass index 25 ± 5 kg m2 ) were included in the study. We performed a shivering threshold test for every participant. Later, we performed 2 h of personalized cold exposure, immediately before a positron emission tomography/computed tomography scan. We showed that 23 of 133 participants had 18 F-FDG uptake in the dorsocervical area that achieved the criteria to be considered BAT, mainly in women (96%, n = 22 of 23). In the whole sample, the glucose uptake in the SAT of the dorsocervical area was positively correlated with BAT volume and activity located in the supraclavicular area. We showed that the 18 F-FDG uptake of the SAT of the dorsocervical area in humans is different from that of other SAT areas. Future studies are warranted to confirm the brown signature of this tissue.

Independent and combined influence of healthy lifestyle factors on academic performance in adolescents: DADOS Study.

BACKGROUND: Few studies have analyzed the combined effect of lifestyle factors on academic performance (AP) in adolescents. The aim of this study was to analyze the independent and combined effects of weight status, screen time, sleep quality, daily meal frequency, cardiorespiratory fitness, and physical activity (PA) on AP in adolescents. METHODS: A total of 262 adolescents (13.9 ± 0.3 years) from the DADOS study were included in the analysis. Weight status was assessed through body mass index (kg/m2). Participants completed questionnaires to evaluate screen time, sleep quality, and daily meal frequency. Cardiorespiratory fitness was assessed by the 20-m shuttle run test. PA was evaluated by a wrist-worn GENEActiv accelerometer. AP was assessed through the final academic grades and a validated questionnaire. RESULTS: Non-overweight status, low screen time, good sleep quality, and proper meal frequency showed independent, positive influence on AP. Moreover, adolescents achieving at least three healthy lifestyles were more likely to be in the high-performance group for academic grades than those achieving ≤1 (math OR: 3.02-9.51, language OR: 3.51-6.76, and grade point average OR: 4.22-9.36). CONCLUSIONS: Although individual healthy lifestyles are independently and positively associated with AP, the cumulative effect of multiple healthy lifestyles have a stronger impact.

Concurrent validity of supraclavicular skin temperature measured with iButtons and infrared thermography as a surrogate marker of brown adipose tissue.

Brown adipose tissue (BAT) thermogenic activity is commonly assessed with a positron emission tomography with computed tomography scan (PET/CT). This technique has several limitations and alternative techniques are needed. Supraclavicular skin temperature measured with iButtons and infrared thermography (IRT) has been proposed as an indirect marker of BAT activity. We studied the concurrent validity of skin temperature measured with iButtons vs. IRT and the association of supraclavicular skin temperature measured with iButtons and IRT with BAT. We measured skin temperature upon a shivering threshold test with iButtons and IRT in 6 different regions in 12 participants (n = 2 men). On a separate day, we determined supraclavicular skin temperature with an iButton and IRT after 2 h of a personalized cooling protocol. Thereafter, we quantified BAT volume and activity by PET/CT. We observed that the absolute differences between the devices were statistically different from 0 (all P < 0.05) after the shivering threshold test. Moreover, we did not find any association between supraclavicular skin temperature measured with iButtons or IRT and BAT 18F-FDG activity (r = -0.213; P = 0.530 and r = -0.079; P = 0.817). However, we observed a negative association of supraclavicular skin temperature measured by IRT with BAT 18F-FDG volume (r = -0.764; P = 0.006), but not with supraclavicular skin temperature measured with iButtons (r = -0.546; P = 0.082). In light of these results, we concluded that the measurement of skin temperature obtained by iButtons and IRT are not comparable. Furthermore, it seems that supraclavicular skin temperature is not associated with BAT 18F-FDG activity, but it appears to be negatively associated with BAT 18F-FDG volume in the case of IRT.

Fitness and academic performance in adolescents. The mediating role of leptin: DADOS study.

We tested the mediating effect of leptin on the association between physical fitness (PF) components and academic performance indicators in healthy adolescents. A total of 263 adolescents (13.9 ± 0.3 years, 47.5% girls, 12.5% overweight) from the DADOS (Deporte, ADOlescencia y Salud) Study were included in the analysis. PF components were assessed by the handgrip test for upper-limb muscular strength, standing long jump test for lower-limb muscular strength, 4 × 10-m shuttle run test for speed-agility, and 20-m shuttle run test for cardiorespiratory fitness. Plasma leptin concentration was assessed from antecubital vein blood after an overnight fast using a sensitive ELISA kit. Academic performance indicators were assessed through final school grades and through the Spanish version of the SRA Test of Educational Ability. Body composition was assessed by body mass index and skinfold thicknesses. Boot-strapped mediation procedures were performed and indirect effects with confidence intervals not including zero were interpreted as statistically significant. Our findings suggest that the positive associations observed between cardiorespiratory fitness and lower-limb muscular strength with academic performance indicators were mediated by leptin concentration after adjusting for sex, pubertal stage, socioeconomic status, and adiposity (percentage of mediation ranging from 54.61 to 82.02%). CONCLUSIONS: Improvements on PF components, particularly in cardiorespiratory fitness and lower-limb muscular strength, might reduce leptin concentration with potential benefits on academic performance in adolescents, independently of adiposity. What is Known: • Academic performance is associated with physical fitness and leptin concentration in children and adolescents. • Fitness modulates leptin concentration levels, regardless of physical activity and adiposity. What is New: • Leptin concentration mediates the association of cardiorespiratory fitness and muscular strength with academic performance in adolescents. • Improvements in cardiorespiratory fitness and muscular strength might reduce leptin concentration levels enhancing academic performance.

Associations Between Pedometer-Determined Physical Activity and Adiposity in Children and Adolescents: Systematic Review.

OBJECTIVE: The present review sought to examine the evidence on the associations between pedometer-determined physical activity and adiposity. DESIGN: Of 304 potentially eligible articles, 36 were included. A search for observational studies was carried out using Cochrane Library (CENTRAL), the OVID (MEDLINE, Embase, and PsycINFO), EBSCOhost (Sportdiscus), and PEDro database from their commenced to July 2015. Of 304 potentially eligible articles, 36 were included. RESULTS: Most studies (30/36; 83%) were cross sectional and all used proxies for adiposity, such as body mass index (BMI) or BMI z-score as the outcome measure. Few studies (2/36; 6%) focused on preschool children. There was consistent evidence of negative associations between walking and adiposity; significant negative associations were observed in 72% (26/36) of studies overall. CONCLUSIONS: The present review supports the hypothesis that higher levels of walking are protective against child and adolescent obesity. However, prospective longitudinal studies are warranted; there is a need for more research on younger children and for more "dose-response" evidence.

Parental modeling, education and children's sports and TV time: the ENERGY-project.

OBJECTIVE: We assessed whether differences in children's sports participation and television time according to parental education were mediated by parental modeling. Moreover, we explored the differences between parental and child reports on parental sports participation and television time as potential mediators. METHODS: 5729 children and 5183 parents participating in the EuropeaN Energy balance Research to prevent excessive weight Gain among Youth (ENERGY-project) during 2010 in seven European countries provided information on sports participation and television time using validated self-report questionnaires. Multilevel country-specific mediation models analyzed the potential mediation effect of parental self-reports and child-reports on parental sports participation and television time. RESULTS: Significant mediation effect was found for parental self-reported television time in four countries (Greece, Hungary, The Netherlands and Slovenia), with the highest proportion for Slovenia (40%) and the lowest for Greece (21%). Child-reported parental television time showed mediation effect in Greece only. Parental self-reported sports participation showed significant mediation effect only in Greece. With child-reported parental sports participation, significant mediation was observed in Greece and Norway. CONCLUSIONS: Parental behaviors appear to be important in explaining parental educational differences in children's sports participation and television time. However, child reports on parental behavior appear to be more relevant than parents' self-reports as correlates of children's own sports participation and television time.

Dietary protein and amino acids intake and its relationship with blood pressure in adolescents: the HELENA STUDY.

OBJECTIVE: To analyze the association between dietary protein and amino acids intake and systolic (SBP) and diastolic (DBP) blood pressure in European adolescents. METHODS: Participants were from the cross-sectional study performed in Europe, Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA study; n = 1605; 12.5-17.5 years; 833 girls) selected by complex sampling. The associations between dietary protein and amino acids intake and SBP/DBP were examined by multilevel linear regression models (context variable by school); the analysis being stratified by sex. Cities, seasonality, age, socioeconomic level, parental education level, body mass index, waist circumference, Tanner stage and physical activity were used as covariates. RESULTS: In boys, we found an inverse association between protein (animal and vegetable) intake and DBP; and a positive association between histidine and SBP. In girls, we observed a positive association among tryptophan, histidine with SBP and methionine with DBP. On the other hand, we observed an inverse association between tyrosine and both SBP and DBP levels in girls. CONCLUSIONS: The association between amino acids and BP levels is controversial and depends on the type of amino acids, and protein intake can help control the DBP in boys.

Family socioeconomic factors are negatively associated with blood pressure in European boys, but not girls, and Brazilian adolescents: Results from two observational studies.

OBJECTIVE: We aimed to estimate the attributable fraction of systolic (SBP) and diastolic blood pressure (DBP) that can be explained by family socioeconomic factors (FSFs) in adolescents using two observational studies. METHODS: Participants were recruited by multistage random cluster in two cross-sectional studies performed in Europe [Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, n = 3308] and Brazil [Brazilian Cardiovascular Adolescent Health (BRACAH) study, n = 991]. SBP and DBP were measured, and FSFs (socioeconomic status and parental education) were self-reported in both studies. The correlations of SBP and DBP with FSFs were examined by multilevel linear regression through two different models (hierarchical and fully adjusted). The generalized attributable fractions of the FSFs were estimated by comparing the models. RESULTS: Our results showed a significant inverse relationship between parental education (father and mother) and SBP in European boys. The higher generalized attributable fraction to SBP was observed in boys (13.2-22.4%). In girls, we found lower generalized attributable fractions to DBP (10.8-12.1% in Brazilian girls and 3.1-3.8% in European girls). CONCLUSIONS: Our findings revealed a significant inverse relationship between parental education and SBP in European boys. FSF also significantly influenced blood pressure in adolescents, mainly in Brazilian adolescents.

Breastfeeding attenuates the effect of low birthweight on abdominal adiposity in adolescents: the HELENA study.

The aim of this study was to examine whether breastfeeding may reduce the programming effect of birthweight on abdominal adiposity. Abdominal (in three regions: R1, R2 and R3) adiposity was measured by dual energy x-ray absorptiometry in 314 adolescents. Breastfeeding duration, birthweight, duration of gestation and maternal educational level were obtained from questionnaire. Physical activity was objectively measured. We detected significant interactions between breastfeeding and birthweight on abdominal adiposity (Ps = 0.02-0.07). We observed that birthweight was associated with abdominal adiposity in the group who had never been breastfed (ß = -0.19 to -0.23; Ps < 0.05), while no association was found in adolescents who had breastfeeding for ≥3 months (ß = -0.03 to -0.07). The results were independent of duration of gestation, age, sex, maternal educational level and physical activity. Breastfeeding may reduce the adverse influence conferred by low birthweight on abdominal adiposity in adolescents.

A systematic review and cluster analysis approach of 103 studies of high-intensity interval training on cardiorespiratory fitness.

AIMS: This study aims to systematically review the systematic reviews and meta-analyses examining the effect of high-intensity interval training (HIIT) protocols on improving cardiorespiratory fitness (CRF) and to characterize the main patterns of HIIT modalities using clustering statistical procedures to examine their potential differences on improving CRF. Finally, we aimed to develop a comprehensive guideline for reporting HIIT protocols. METHODS AND RESULTS: A systematic review was conducted on PubMed and Web of Science from their inception to 31 October 2022 for systematic reviews and meta-analysis aimed at assessing the effect of HIIT on CRF in the entire study population. The Assessment of Multiple Systematic Reviews 2 tool was used to evaluate the risk of bias of each review. Additionally, a principal component analysis testing the data adequacy for the factor solution through the Kaiser-Meyer-Olkin procedure test was conducted. Once the number of factors was identified, in order to identify data patterns according to the main characteristics of the HIIT protocols, a two-step cluster analysis was conducted. Nineteen systematic reviews and/or meta-analyses comprising 103 studies were included. Clustering of systematic reviews and meta-analyses identified three HIIT modalities ('HIIT-normal mixed', 'HIIT-long running', and 'HIIT-short cycling') underlying the interventions across the included studies. Similar effectiveness in increasing CRF among the three HIIT modalities was observed. Subgroup analyses showed no significant differences in CRF by sex, weight status, study design, and baseline physical activity level (P > 0.05), but differences were observed by age group, and exercise intensity indicator was used in the HIIT programmes (P < 0.05). CONCLUSION: All three HIIT modalities produced significant improvements of CRF, although some modalities showed greater changes for some specific age groups or intensity indicators.

In this review, including data from more than 100 individual studies, 3 patterns of high-intensity interval training (HIIT), 'HIIT-normal mixed', 'HIIT-long running', and 'HIIT-short cycling', were characterized using a cluster analysis approach. Independently of the sex, weight status, study design, and baseline physical activity level, all three proposed HIIT modalities improved cardiorespiratory fitness (CRF). However, for the age group of 20­44 years, the 'HIIT-long running' reported greater improvement in CRF than 'HIIT-short cycling'. Additionally, the heart rate as an intensity indicator reported higher CRF in 'HIIT-long running' compared with 'HIIT-normal mixed'. A HIIT reporting guideline is provided to address the lack of information on HIIT protocols and provide transparency among studies.

Sleep Behaviors and the Shape of Subcortical Brain Structures in Children with Overweight/Obesity: A Cross-Sectional Study.

OBJECTIVES: To examine the relationship between sleep and subcortical brain structures using a shape analysis approach. METHODS: A total of 98 children with overweight/obesity (10.0 ± 1.1 y, 59 boys) were included in the cross-sectional analyses. Sleep behaviors (i.e., wake time, sleep onset time, total time in bed, total sleep time, sleep efficiency, and wakening after sleep onset) were estimated with wrist-worn accelerometers. The shape of the subcortical brain structures was acquired by magnetic resonance imaging. A partial correlation permutation approach was used to examine the relationship between sleep behaviors and brain shapes. RESULTS: Among all the sleep variables studied, only total time in bed was significantly related to pallidum and putamen structure, such that those children who spent more time in bed had greater expansions in the right and left pallidum (211-751 voxels, all p's <0.04) and right putamen (1783 voxels, p = 0.03). CONCLUSIONS: These findings suggest that more time in bed was related to expansions on two subcortical brain regions in children with overweight/obesity.

Association of physical behaviours with sarcopenia in older adults: a systematic review and meta-analysis of observational studies.

BACKGROUND: Physical behaviours (ie, physical activity and sedentary behaviour) might have a role in the development of sarcopenia, although the evidence is unclear. We aimed to explore the association of total and intensity-specific levels of physical activity and sedentary behaviour with sarcopenia and its components (ie, muscle mass, muscle strength, and physical performance) in older adults. METHODS: We conducted a systematic review and meta-analysis and searched MEDLINE (via PubMed), Scopus, and Web of Science from inception to July 26, 2022, for peer-reviewed, observational studies or baseline data from randomised clinical trials conducted in older adults (ie, individual age ≥60 years or mean age ≥65 years) and published in English that reported on the association of physical activity or sedentary behaviour or both with sarcopenia (or its determinants: muscle mass or strength, and physical performance). Physical activity and sedentary behaviour were measured by any method. The main outcome was sarcopenia, which could be diagnosed by any means. Estimates were extracted and pooled using Bayesian meta-analytic models and publication bias was assessed using the Egger's test. This study is registered with PROSPERO, CRD42022315865. FINDINGS: We identified 15 766 records, of which 124 studies (230 174 older adults; 121 301 [52·7%] were female and 108 873 [47·3%] were male) were included in the systematic review. 86 studies were subsequently included in the meta-analysis. Higher levels of total physical activity were inversely associated with sarcopenia both cross-sectionally (21 studies, n=59 572; odds ratio 0·49, 95% credible interval 0·37-0·62) and longitudinally (four studies, n=7545; 0·51, 0·27-0·94). A protective association was also identified for moderate-to-vigorous physical activity in cross-sectional research (five studies, n=6787; 0·85, 0·71-0·99), whereas no association was identified for the remaining physical behaviours (ie, steps, light physical activity, or sedentary behaviour). INTERPRETATION: Total and moderate-to-vigorous physical activity are inversely associated with sarcopenia. These findings might support the importance of moderate-to-vigorous, rather than light, intensity physical activity-based interventions to prevent sarcopenia. FUNDING: None. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.