Exchanging screen for non-screen sitting time or physical activity might attenuate depression and anxiety: A cross-sectional isotemporal analysis during early pandemics in South America.

OBJECTIVES: To examine the theoretical substitutions of screen exposure, non-screen sitting time, moderate and vigorous physical activity with depressive and anxiety symptoms in South American adults during the COVID-19 pandemic. DESIGN: A cross-sectional study during the first months of the COVID-19 pandemic with data from 1981 adults from Chile, Argentina, and Brazil. METHODS: Depressive and anxiety symptoms were assessed using the Beck Depression and Anxiety Inventories. Participants also reported physical activity, sitting time, screen exposure, sociodemographic, and tobacco use data. Isotemporal substitution models were created using multivariable linear regression methods. RESULTS: Vigorous physical activity, moderate physical activity, and screen exposure were independently associated with depression and anxiety symptoms. In adjusted isotemporal substitution models, replacing 10 min/day of either screen exposure or non-screen sitting time with any intensity of physical activity was associated with lower levels of depressive symptoms. Improvements in anxiety symptoms were found when reallocating either screen exposure or non-screen sitting time to moderate physical activity. Furthermore, replacing 10 min/day of screen exposure with non-screen sitting time was beneficially associated with anxiety (B = -0.033; 95 % CI = -0.059, -0.006) and depression (B = -0.026; 95 % CI = -0.050, -0.002). CONCLUSIONS: Replacement of screen exposure with any intensity of physical activity or non-screen sitting time could improve mental health symptoms. Strategies aiming to reduce depressive and anxiety symptoms highlight physical activity promotion. However, future interventions should explore specific sedentary behaviors as some will relate positively while others negatively.

Global Matrix 4.0 Physical Activity Report Card Grades for Children and Adolescents: Results and Analyses From 57 Countries.

BACKGROUND: The Global Matrix 4.0 on physical activity (PA) for children and adolescents was developed to achieve a comprehensive understanding of the global variation in children's and adolescents' (5-17 y) PA, related measures, and key sources of influence. The objectives of this article were (1) to summarize the findings from the Global Matrix 4.0 Report Cards, (2) to compare indicators across countries, and (3) to explore trends related to the Human Development Index and geo-cultural regions. METHODS: A total of 57 Report Card teams followed a harmonized process to grade the 10 common PA indicators. An online survey was conducted to collect Report Card Leaders' top 3 priorities for each PA indicator and their opinions on how the COVID-19 pandemic impacted child and adolescent PA indicators in their country. RESULTS: Overall Physical Activity was the indicator with the lowest global average grade (D), while School and Community and Environment were the indicators with the highest global average grade (C+). An overview of the global situation in terms of surveillance and prevalence is provided for all 10 common PA indicators, followed by priorities and examples to support the development of strategies and policies internationally. CONCLUSIONS: The Global Matrix 4.0 represents the largest compilation of children's and adolescents' PA indicators to date. While variation in data sources informing the grades across countries was observed, this initiative highlighted low PA levels in children and adolescents globally. Measures to contain the COVID-19 pandemic, local/international conflicts, climate change, and economic change threaten to worsen this situation.

Changes in Sitting Time, Screen Exposure and Physical Activity during COVID-19 Lockdown in South American Adults: A Cross-Sectional Study.

The worldwide prevalence of insufficient physical activity (PA) and prolonged sedentary behavior (SB) were high before the coronavirus (COVID-19) pandemic. Measures that were taken by governments (such as home confinement) to control the spread of COVID-19 may have affected levels of PA and SB. This cross-sectional study among South American adults during the first months of COVID-19 aims to (i) compare sitting time (ST), screen exposure, moderate PA (MPA), vigorous PA (VPA), and moderate-to-vigorous PA (MVPA) before and during lockdown to sociodemographic correlates and (ii) to assess the impact of lockdown on combinations of groups reporting meeting/not-meeting PA recommendations and engaging/not-engaging excessive ST (≥7 h/day). Bivariate associations, effect sizes, and multivariable linear regressions were used. Adults from Argentina (n = 575) and Chile (n = 730) completed an online survey with questions regarding demographics, lifestyle factors, and chronic diseases. Mean reductions of 42.7 and 22.0 min./day were shown in MPA and VPA, respectively; while increases of 212.4 and 164.3 min./day were observed in screen and ST, respectively. Those who met PA recommendations and spent <7 h/day of ST experienced greatest changes, reporting greater than 3 h/day higher ST and more than 1.5 h/day lower MVPA. Findings from the present study suggest that efforts to promote PA to South American adults during and after COVID-19 restrictions are needed.

Effects of a rehabilitation program on microvascular function of CHD patients assessed by near-infrared spectroscopy.

This study aimed to evaluate whether near-infrared spectroscopy (NIRS)-derived reperfusion slope would detect the effects of a 12-week rehabilitation program on lower limb microvascular responsiveness in patients with coronary heart disease (CHD). Ten CHD patients (7 males and 3 females; 57.3 ± 7.6 years) underwent 12 weeks of drug treatment and high-intensity interval training (HIIT), 2 times per week (40 min/session). Microvascular responsiveness was assessed by using NIRS assessment of muscle oxygen saturation (StO2 ) combined with a vascular occlusion test (VOT) (NIRS-VOT). NIRS-VOT measures were taken at pre- and postintervention, and microvascular responsiveness was evaluated by examining the slope 2 of re-oxygenation rate (slope 2 StO2 ) and the area under the curve (StO2AUC ) of StO2 signal following cuff release subsequent to a 5-min occlusion period. The slope 2 StO2 was significantly steeper after 12 weeks of training (4.8 ± 1.6% sec-1 ) compared to the pretraining (3.1 ± 1.6% sec-1 ) (P < 0.05). The area under the curve for the change in the % StO2 signal during re-oxygenation increased significantly from 3494 ± 2372%∙sec at pretraining to 9006 ± 4311%∙sec at post-training (P < 0.05). NIRS-VOT technique detected the improvements of 12 weeks of rehabilitation program in the lower limb microvascular responsiveness of CHD patients.

Anthropometrics of Italian Senior Male Rugby Union Players: From Elite to Second Division.

UNLABELLED: Anthropometric evaluation of athletes is necessary to optimize talent identification and player development. OBJECTIVES: To provide a specific anthropometric reference database of senior male rugby players competing at different levels in the southern European region. DESIGN: Cross-sectional. METHODS: In 362 professional players (25 ± 4 y; 138 Italian national team, 97 first-division, and 127 second-division national championships) the authors measured mass, stature, and percentage body fat (plicometry). Mean, SD, and coefficient of variation were calculated for forwards and backs and for positional subgroups. Binomial logistic regression and receiver-operating-characteristic curve were performed to assess which variables best predicted level assignment (international vs national level). RESULTS: For all competitive levels forwards were significantly heavier and taller and had a larger percentage body fat and fat-free mass than backs. The lower the competitive level, the higher the within-role variability observed; furthermore, players in a specific positional subgroup were lighter, shorter, and fatter and had less fat-free mass. Fatfree mass is the variable that best predicts the likelihood of being classified as an international or national player (cutoff value 79.54 kg). CONCLUSIONS: The data confirm the specificity in the physical requirements of rugby in individual playing positions at all competitive levels and document significant differences among elite and 1st- and 2nd-division players in the same positional role. These differences may reflect the variable technical abilities, selection, training practices, and requirements of the game among these categories.

Determination of respiratory point compensation in healthy adults: Can non-invasive near-infrared spectroscopy help?

OBJECTIVES: We tested the hypothesis that the respiratory compensation point can be accurately determined in healthy participants during incremental cycling exercise using non-invasive near-infrared spectroscopy-derived measures of deoxygenated hemoglobin (deoxyHb). DESIGN: Validation study. METHODS: 118 healthy men (average age 47 ± 19 yrs, range 20-79 yrs) performed an incremental cycling test to exhaustion. Breath-by-breath pulmonary oxygen uptake (VO2) and other ventilatory and gas exchange variables were measured and used to determine respiratory compensation point. Vastus lateralis deoxyHb was monitored using a frequency domain multi-distance system near-infrared spectroscopy device and deoxyHb data were modeled with a piece-wise double-linear function from which the deoxyHb deflection point (deoxyHbDP) was determined. The absolute (L min(-1)) and relative (% maximal VO2 [VO 2max]) VO2 values associated with the respiratory compensation point and deoxyHbDP were determined for each individual. RESULTS: DeoxyHb increased as a function of exercise intensity up to a point (deoxyHbDP) after which the signal displayed a "near-plateau". The deoxyHbDP corresponded to a VO2 of 2.25 ± 0.69 L min(-1) (74 ± 12% VO 2max) which was not significantly different from the VO2 at respiratory compensation point (2.28 ± 0.70 L min(-1) and 74 ± 10% VO 2max, p < 0.05). Both indices were highly correlated (r(2) = 0.86) and Bland Altman analyses confirmed a non-significant bias for VO2 (-0.024 L min(-1)) concomitant with a small imprecision of 0.26 L min(-1). CONCLUSIONS: During incremental cycling exercise, the VO2 associated with the onset of a plateau in near-infrared spectroscopy-derived deoxyHb occurs in coincidence with the VO2 at respiratory compensation point suggesting that respiratory compensation point can be accurately estimated, non-invasively, using near-infrared spectroscopy-derived deoxyHb in alternative to the use of ventilatory-based techniques.

Effects of priming exercise on the speed of adjustment of muscle oxidative metabolism at the onset of moderate-intensity step transitions in older adults.

Aging is associated with a functional decline of the oxidative metabolism due to progressive limitations of both O(2) delivery and utilization. Priming exercise (PE) increases the speed of adjustment of oxidative metabolism during successive moderate-intensity transitions. We tested the hypothesis that such improvement is due to a better matching of O(2) delivery to utilization within the working muscles. In 21 healthy older adults (65.7 ± 5 yr), we measured contemporaneously noninvasive indexes of the overall speed of adjustment of the oxidative metabolism (i.e., pulmonary Vo(2) kinetics), of the bulk O(2) delivery (i.e., cardiac output), and of the rate of muscle deoxygenation (i.e., deoxygenated hemoglobin, HHb) during moderate-intensity step transitions, either with (ModB) or without (ModA) prior PE. The local matching of O(2) delivery to utilization was evaluated by the ΔHHb/ΔVo(2) ratio index. The overall speed of adjustment of the Vo(2) kinetics was significantly increased in ModB compared with ModA (P < 0.05). On the contrary, the kinetics of cardiac output was unaffected by PE. At the muscle level, ModB was associated with a significant reduction of the "overshoot" in the ΔHHb/ΔVo(2) ratio compared with ModA (P < 0.05), suggesting an improved O(2) delivery. Our data are compatible with the hypothesis that, in older adults, PE, prior to moderate-intensity exercise, beneficially affects the speed of adjustment of oxidative metabolism due to an acute improvement of the local matching of O(2) delivery to utilization.

Cardiovascular determinants of maximal oxygen consumption in upright and supine posture at the end of prolonged bed rest in humans.

We tested the hypothesis that, after bed rest, maximal oxygen consumption ( VO2max ) decreases more upright than supine, because of adequate cardiovascular response supine, but not upright. On 9 subjects, we determined VO2max and maximal cardiac output (Q ) upright and supine, before and after (reambulation day upright, the following day supine) 35-day bed rest, by classical steady state protocol. Oxygen consumption, heart rate (f(H)) and stroke volume (Q(st)) were measured by a metabolic cart, electrocardiography and Modelflow from pulse pressure profiles, respectively. We computed Q as f(H) times Q(st), and systemic oxygen flow ( QaO2) as Q. times arterial oxygen concentration, obtained after haemoglobin and arterial oxygen saturation measurements. Before bed rest, all parameters at maximal exercise were similar upright and supine. After bed rest, VO2max was lower (p<0.05) than before, both upright (-38.6%) and supine (-17.0%), being 30.8% higher supine than upright. Maximal Q(st) decreased upright (-44.3%), but not supine (+3.7%), being 98.9% higher supine than upright. Maximal Q decreased upright (-45.1%), but not supine (+9.0%), being higher supine than upright (+98.4%). Maximal QaO2 decreased upright (-37.8%), but not supine (+14.8%), being higher (+74.8%) upright than supine. After bed rest, the cardiovascular response (i) did not affect VO2max supine, (ii) partially explained the VO2max decrease upright, and (iii) caused the VO2max differences between postures. We speculate that impaired peripheral oxygen transfer and/or utilisation may explain the VO2max decrease supine and the fraction of VO2max decrease upright unexplained by cardiovascular responses.