Effects of age on human skeletal muscle: a systematic review and meta-analysis of myosin heavy chain isoform protein expression, fiber size, and distribution.

Human studies examining the cellular mechanisms behind sarcopenia, or age-related loss of skeletal muscle mass and function, have produced inconsistent results. A systematic review and meta-analysis were performed to determine the aging effects on protein expression, size, and distribution of fibers with various myosin heavy chain (MyHC) isoforms. Study eligibility included MyHC comparisons between young (18-49 yr) and older (≥60 yr) adults, with 27 studies identified.

Effects of older age on contraction-induced intramyocellular acidosis and inorganic phosphate accumulation in vivo: A systematic review and meta-analysis.

Although it is clear that the bioenergetic basis of skeletal muscle fatigue (transient decrease in peak torque or power in response to contraction) involves intramyocellular acidosis (decreased pH) and accumulation of inorganic phosphate (Pi) in response to the increased energy demand of contractions, the effects of old age on the build-up of these metabolites has not been evaluated systematically. The purpose of this study was to compare pH and [Pi] in young (18-45 yr) and older (55+ yr) human skeletal muscle in vivo at the end of standardized contraction protocols. Full study details were prospectively registered on PROSPERO (CRD42022348972).

Advancing Wearable Biosensors for Congenital Heart Disease: Patient and Clinician Perspectives: A Science Advisory From the American Heart Association.

Wearable biosensors (wearables) enable continual, noninvasive physiologic and behavioral monitoring at home for those with pediatric or congenital heart disease. Wearables allow patients to access their personal data and monitor their health. Despite substantial technologic advances in recent years, issues with hardware design, data analysis, and integration into the clinical workflow prevent wearables from reaching their potential in high-risk congenital heart disease populations.

Resistance Exercise Training in Individuals With and Without Cardiovascular Disease: 2023 Update: A Scientific Statement From the American Heart Association.

Resistance training not only can improve or maintain muscle mass and strength, but also has favorable physiological and clinical effects on cardiovascular disease and risk factors. This scientific statement is an update of the previous (2007) American Heart Association scientific statement regarding resistance training and cardiovascular disease. Since 2007, accumulating evidence suggests resistance training is a safe and effective approach for improving cardiovascular health in adults with and without cardiovascular disease.

Comparative Analysis of ActiGraph Step Counting Methods in Adults: A Systematic Literature Review and Meta-Analysis.

Purpose: The primary aim of this study was to compare steps per day across ActiGraph models, wear locations, and filtering methods. A secondary aim was to compare ActiGraph steps per day to those estimated by the ankle-worn StepWatch.

Methods: We conducted a systematic literature review to identify studies of adults published before May 12, 2022, that compared free-living steps per day of ActiGraph step counting methods and studies that compared ActiGraph to StepWatch.

Increasing Equity of Physical Activity Promotion for Optimal Cardiovascular Health in Adults: A Scientific Statement From the American Heart Association.

Fewer than 1 in 4 adults achieves the recommended amount of physical activity, with lower activity levels reported among some groups. Addressing low levels of physical activity among underresourced groups provides a modifiable target with the potential to improve equity in cardiovascular health. This article (1) examines physical activity levels across strata of cardiovascular disease risk factors, individual level characteristics, and environmental factors; (2) reviews strategies for increasing physical activity in groups who are underresourced or at risk for poor cardiovascular health; and (3) provides practical suggestions for physical activity promotion to increase equity of risk reduction and to improve cardiovascular health.

Prospective Association of Daily Steps With Cardiovascular Disease: A Harmonized Meta-Analysis.

Background: Taking fewer than the widely promoted "10 000 steps per day" has recently been associated with lower risk of all-cause mortality. The relationship of steps and cardiovascular disease (CVD) risk remains poorly described. A meta-analysis examining the dose-response relationship between steps per day and CVD can help inform clinical and public health guidelines.

Daily steps and all-cause mortality: a meta-analysis of 15 international cohorts.

Background: Although 10 000 steps per day is widely promoted to have health benefits, there is little evidence to support this recommendation. We aimed to determine the association between number of steps per day and stepping rate with all-cause mortality.

Methods: In this meta-analysis, we identified studies investigating the effect of daily step count on all-cause mortality in adults (aged ≥18 years), via a previously published systematic review and expert knowledge of the field.

Supporting Physical Activity in Patients and Populations During Life Events and Transitions: A Scientific Statement From the American Heart Association.

Achieving recommended levels of physical activity is important for optimal cardiovascular health and can help reduce cardiovascular disease risk. Emerging evidence suggests that physical activity fluctuates throughout the life course. Some life events and transitions are associated with reductions in physical activity and, potentially, increases in sedentary behavior.

Steps per Day and All-Cause Mortality in Middle-aged Adults in the Coronary Artery Risk Development in Young Adults Study.

Importance: Steps per day is a meaningful metric for physical activity promotion in clinical and population settings. To guide promotion strategies of step goals, it is important to understand the association of steps with clinical end points, including mortality.

Objective: To estimate the association of steps per day with premature (age 41-65 years) all-cause mortality among Black and White men and women.

Estimated Impact of Achieving Optimal Cardiovascular Health Among US Adults on Cardiovascular Disease Events.

Background Better cardiovascular health (CVH) scores are associated with lower risk of cardiovascular disease (CVD). However, estimates of the potential population-level impact of improving CVH on US CVD event rates are not currently available. Methods and Results Using data from the National Health and Nutrition Examination Survey 2011 to 2016 (n=11 696), we estimated the proportions of US adults in CVH groups.

The role of the built environment in promoting movement and physical activity across the lifespan: Implications for public health.

Engaging in regular physical activity (PA) and reducing time spent in sedentary behaviors is critically important to prevent and control non-communicable diseases (NCDs). However, global public health efforts to promote and encourage maintenance of PA behavior on a population level remains challenging. To address what is now described as a global physical inactivity pandemic, a breadth of research has focused on understanding the relation of built environment characteristics, including aspects of urban design, transportation and land-use planning, to PA behavior across multiple domains in life, and subsequently how changes in environmental attributes influence changes in PA patterns in diverse populations and subgroups.

Cardiovascular Health Score and Lifetime Risk of Cardiovascular Disease: The Cardiovascular Lifetime Risk Pooling Project.

Background: Long-term risks of cardiovascular disease (CVD) according to levels of cardiovascular health (CVH) have not been characterized in a diverse, representative population.

Methods And Results: We pooled individual-level data from 30 447 participants (mean [SD] age, 55.0 [13.

Systematic review of the prospective association of daily step counts with risk of mortality, cardiovascular disease, and dysglycemia.

Background: Daily step counts is an intuitive metric that has demonstrated success in motivating physical activity in adults and may hold potential for future public health physical activity recommendations. This review seeks to clarify the pattern of the associations between daily steps and subsequent all-cause mortality, cardiovascular disease (CVD) morbidity and mortality, and dysglycemia, as well as the number of daily steps needed for health outcomes.

Methods: A systematic review was conducted to identify prospective studies assessing daily step count measured by pedometer or accelerometer and their associations with all-cause mortality, CVD morbidity or mortality, and dysglycemia (dysglycemia or diabetes incidence, insulin sensitivity, fasting glucose, HbA1c).

The Effect of Exercise Training on Total Daily Energy Expenditure and Body Composition in Weight-Stable Adults: A Randomized, Controlled Trial.

Background: The present study examined, among weight-stable overweight or obese adults, the effect of increasing doses of exercise energy expenditure (EEex) on changes in total daily energy expenditure (TDEE), total body energy stores, and body composition.

Methods: Healthy, sedentary overweight/obese young adults were randomized to one of 3 groups for a period of 26 weeks: moderate-exercise (EEex goal of 17.5 kcal/kg/wk), high-exercise (EEex goal of 35 kcal/kg/wk), or observation group.

Association of Fitness With Racial Differences in Chronic Kidney Disease.

Introduction: Non-white minorities are at higher risk for chronic kidney disease than non-Hispanic whites. Better cardiorespiratory fitness is associated with slower declines in estimated glomerular filtration rate and a lower incidence of chronic kidney disease. Little is known regarding associations of fitness with racial disparities in chronic kidney disease.

Changes in sedentary time are associated with changes in mental wellbeing over 1 year in young adults.

Excessive sedentary time is related to poor mental health. However, much of the current literature uses cross-sectional data and/or self-reported sedentary time, and does not assess factors such as sedentary bout length. To address these limitations, the influence of objectively measured sedentary time including sedentary bout length (i.

The Influence of Life Events and Psychological Stress on Objectively Measured Physical Activity: A 12-Month Longitudinal Study.

Background: This study examined how life event occurrences and stressfulness influence objectively measured light through vigorous physical activity (PA) among young adults.

Methods: Every 3 months over a 12-month period, 404 healthy young adults completed questionnaires on the occurrence and stress of 16 life events and wore an accelerometer for 10 days.

Results: A modest positive relationship was seen between cumulative life event occurrences [between effect: β = 22.

Low levels of physical activity are associated with dysregulation of energy intake and fat mass gain over 1 year.

Background: Previous studies suggest that appetite may be dysregulated at low levels of activity, creating an energy imbalance that results in weight gain.

Objective: The aim was to examine the relation between energy intake, physical activity, appetite, and weight gain during a 1-y follow-up period in a large sample of adults.

Design: Participants included 421 individuals (mean ± SD age: 27.

Association between actigraphic sleep metrics and body composition.

Purpose: Determine if individuals with poor sleep characteristics (i.e., late sleep onset or wake times, short sleep duration, long sleep latency, low sleep efficiency, high wake after sleep onset) have greater body mass index (BMI = kg/m(2)) or body fat.

Subjective Estimation of Physical Activity Using the International Physical Activity Questionnaire Varies by Fitness Level.

Background: Subjective measures of moderate and vigorous physical activity (MVPA) rely on relative intensity whereas objective measures capture absolute intensity; thus, fit individuals and unfit individuals may perceive the same activity differently.

Methods: Adults (N = 211) wore the SenseWear Armband (SWA) for 10 consecutive days to objectively assess sedentary time and MVPA. On day 8, participants completed the International Physical Activity Questionnaire (IPAQ) to subjectively assess sitting time and MVPA.

Moderate cardiorespiratory fitness is positively associated with resting metabolic rate in young adults.

Objective: To determine whether moderate cardiorespiratory fitness (CRF) or moderate to vigorous physical activity (MVPA) is associated with elevations in resting metabolic rate (RMR) similar to findings previously observed in endurance athletes.

Participants And Methods: Using a cross-sectional design, we measured CRF, RMR, body composition, energy expenditure, and time in MVPA via an arm-based activity monitor in 423 young adults (mean age, 27.6 years).

Low fitness partially explains resting metabolic rate differences between African American and white women.

Background: High levels of obesity among African American women have been hypothesized to be partially resultant from a lower resting metabolic rate compared with white women. The aim of the current study was to determine if differences in cardiorespiratory fitness and moderate-to-vigorous physical activity are associated with differences in resting metabolic rate among free-living young adult African American women and white women.

Methods: Participants were 179 women (white women n = 141, African American women n = 38, mean age = 27.

The energy balance study: the design and baseline results for a longitudinal study of energy balance.

Purpose: The Energy Balance Study (EBS) was a comprehensive study designed to determine over a period of 12 months the associations of caloric intake and energy expenditure on changes in body weight and composition in a population of healthy men and women.

Method: EBS recruited men and women aged 21 to 35 years with a body mass index between 20 and 35 kg/m2. Measurements of energy intake and multiple objective measures of energy expenditure, as well as other physiological, anthropomorphic and psychosocial measurements, were made quarterly.