Aerobic, resistance, or combined exercise training and cardiovascular risk profile in overweight or obese adults: the CardioRACE trial.

BACKGROUND AND AIMS: To determine the comparative efficacy of resistance, aerobic, and combined resistance plus aerobic exercise on cardiovascular disease (CVD) risk profile. METHODS: This randomized controlled trial enrolled 406 adults aged 35-70 years with overweight or obesity and elevated blood pressure. Participants were randomly assigned to resistance (n = 102), aerobic (n = 101), combined resistance plus aerobic exercise (n = 101), or no-exercise control (n = 102). All exercise participants were prescribed 1 h of time-matched supervised exercise (the combination group with 30 min of each resistance and aerobic exercise) three times per week for 1 year. The primary outcome was the change from baseline to 1 year in the standardized composite Z-score of four well-established CVD risk factors: systolic blood pressure, low-density lipoprotein (LDL) cholesterol, fasting glucose, and per cent body fat. RESULTS: Among 406 participants (53% women), 381 (94%) completed 1-year follow-up. Compared with the control group, the composite Z-score decreased at 1 year, which indicates improved CVD risk profile, in the aerobic {mean difference, -0.15 [95% confidence interval (CI): -0.27 to -0.04]; P = .01} and combination [mean difference, -0.16 (95% CI: -0.27 to -0.04); P = .009] groups, but not in the resistance [mean difference, -0.02 (95% CI: -0.14 to 0.09); P = .69] group. Both aerobic and combination groups had greater reductions in the composite Z-score compared with the resistance group (both P = .03), and there was no difference between the aerobic and combination groups (P = .96). Regarding the four individual CVD risk factors, only per cent body fat decreased in all three exercise groups at 1 year, but systolic blood pressure, LDL cholesterol, and fasting glucose did not decrease in any exercise groups, compared with the control group. CONCLUSIONS: In adults with overweight or obesity, aerobic exercise alone or combined resistance plus aerobic exercise, but not resistance exercise alone, improved composite CVD risk profile compared with the control.

A cluster-randomized trial comparing two SWITCH implementation support strategies for school wellness intervention effectiveness.

BACKGROUND: The School Wellness Integration Targeting Child Health (SWITCH) intervention has demonstrated feasibility as an implementation approach to help schools facilitate changes in students' physical activity (PA), sedentary screen time (SST), and dietary intake (DI). This study evaluated the comparative effectiveness of enhanced (individualized) implementation and standard (group-based) implementation. METHODS: Twenty-two Iowa elementary schools participated, with each receiving standardized training (wellness conference and webinars). Schools were matched within region and randomized to receive either individualized or group implementation support. The PA, SST, and DI outcomes of 1097 students were assessed at pre- and post-intervention periods using the Youth Activity Profile. Linear mixed models evaluated differential change in outcomes by condition, for comparative effectiveness, and by gender. RESULTS: Both implementation conditions led to significant improvements in PA and SST over time (p < 0.01), but DI did not improve commensurately (p value range: 0.02‒0.05). There were no differential changes between the group and individualized conditions for PA (p = 0.51), SST (p = 0.19), or DI (p = 0.73). There were no differential effects by gender (i.e., non-significant condition-by-gender interactions) for PA (pfor interaction = 0.86), SST (pfor interaction = 0.46), or DI (pfor interaction = 0.15). Effect sizes for both conditions equated to approximately 6 min more PA per day and approximately 3 min less sedentary time. CONCLUSION: The observed lack of difference in outcomes suggests that group implementation of SWITCH is equally effective as individualized implementation for building capacity in school wellness programming. Similarly, the lack of interaction by gender suggests that SWITCH can be beneficial for both boys and girls. Additional research is needed to understand the school-level factors that influence implementation (and outcomes) of SWITCH.

Comparison of the Cardiovascular Benefits of Resistance, Aerobic, and Combined Exercise (CardioRACE): Rationale, design, and methods.

BACKGROUND: The benefits of aerobic exercise (AE) for cardiovascular disease (CVD) have been well documented. Resistance exercise (RE) has been traditionally examined for its effects on bone density, physical function, or metabolic health, yet few data exist regarding the benefits of RE, independent of and combined with AE, for CVD prevention. This randomized controlled trial, "Comparison of the Cardiovascular Benefits of Resistance, Aerobic, and Combined Exercise (CardioRACE)," is designed to determine the relative benefits of RE, AE, or combined RE plus AE training on CVD risk factors. METHODS: Participants are 406 inactive men and women (35-70 years) with a body mass index of 25-40 kg/m2 and blood pressure (BP) of 120-139/80-89 mm Hg without taking antihypertensive medications. Participants are randomly assigned to RE only, AE only, combined RE and AE (CE), or a no exercise control group. Participants perform supervised exercise at 50%-80% of their relative maximum intensity for both AE and RE, 3 times a week for 60 minutes per session, for 1 year (all 3 groups are time matched). RESULTS: The primary outcome is a composite z score including resting BP, low-density lipoprotein cholesterol (LDL-C), fasting glucose, and percent body fat, which is assessed at baseline, 6 months, and 12 months. Diet and outside physical activity are measured throughout the intervention for 1 year. CONCLUSION: CardioRACE (ClinicalTrials.govNCT03069092) will fill an important knowledge gap regarding the effects of RE, alone or in addition to the well-documented effects of AE. CardioRACE will help generate more comprehensive and synergistic clinical and public health strategies to prevent CVD.

Worksite Physical Activity Intervention for Ambulatory Clinic Nursing Staff.

Health behaviors, including physical activity (PA), of registered nurses (RNs) and medical assistants (MAs) are suboptimal but may improve with worksite programs. Using a repeated-measures crossover design, the authors explored if integrating a 6-month worksite non-exercise activity thermogenesis (NEAT) intervention, with and without personalized health coaching via text messaging into workflow could positively affect sedentary time, PA, and body composition of nursing staff without jeopardizing work productivity. Two ambulatory clinics were randomly assigned to an environmental NEAT intervention plus a mobile text message coaching for either the first 3 months (early texting group, n = 27) or the last 3 months (delayed texting group, n = 13), with baseline 3-month and 6-month measurements. Sedentary and PA levels, fat mass, and weight improved for both groups, significantly only for the early text group. Productivity did not decline for either group. This worksite intervention is feasible and may benefit nursing staff.

Nurse-Led School-Based Child Obesity Prevention.

School-based childhood obesity prevention programs have grown in response to reductions in child physical activity (PA), increased sedentariness, poor diet, and soaring child obesity rates. Multiple systematic reviews indicate school-based obesity prevention/treatment interventions are effective, yet few studies have examined the school nurse role in obesity interventions. Building on a previous study, this study examines a refined health messaging (Let's Go 5-2-1-0) program delivered to fourth and fifth graders (n = 72) by a school nurse with reinforcement on-site health coaching by senior nursing students. Two nursing schools and two elementary schools participated. Measures of PA, body mass index percentile, and self-reported health habits were collected at baseline (School A, September 2009 and School B, January 2010) and end of year (April 2010 for both schools). Findings included statistically significant increases in PA levels and improvements in child-reported health habits. School nurses can influence obesity prevention. Further research on adoption of school nurse-led obesity interventions is warranted.

Validity of the SenseWear® Armband to predict energy expenditure in pregnant women.

UNLABELLED: Few valid, objective methods exist to quantify physical activity and predict energy expenditure (EE) during pregnancy. PURPOSE: The purpose of this study was to evaluate the validity of the SenseWear Mini armband monitor (SWA) (BodyMedia, Pittsburgh, PA) to estimate EE in pregnant women. METHODS: Thirty healthy pregnant women (22-24 wk of gestation) completed a series of activities of daily living (typing, laundry, sweeping, and treadmill walking: 2.0, 2.5, 3.0, and 3.0 mph, 3% incline) while EE was estimated by the SWA and measured by indirect calorimetry (IC). The SWA data were processed using both the v2.2 algorithm and the newer v5.2 algorithm. The estimated EE values were compared with the measured EE values using a three-way (method × algorithm × activity) mixed model ANOVA. Least square means ± SE were estimated in the model. Significance was set at P < 0.05. RESULTS: The analyses revealed a significant method (IC vs. SWA) × algorithm (v5.2 vs. v2.2) interaction with significantly smaller error (IC-SWA) for the newer v5.2 algorithm (-0.57 ± 0.06 kcal.min(-1)) than the older v2.2 algorithm (-0.78 ± 0.06 kcal.min(-1)). The SWA significantly overestimated EE for all activities, except inclined walking. The average mean absolute percentage error was considerably lower for the new algorithm (22%) than that for the older algorithm (35%). The average individual correlation coefficients revealed good overall agreement between the SWA and the IC (v5.2, mean r = 0.93; v2.2, mean r = 0.87). CONCLUSION: Overall, the SWA correlated well with IC; however, EE was significantly overestimated during most activities. Future studies should develop pregnancy-specific algorithms and assess validity of the SWA at all stages of pregnancy to further improve prediction of EE in this population.

Effects of a worksite physical activity intervention for hospital nurses who are working mothers.

Hospital nurses who are working mothers are challenged to maintain their personal health and model healthy behaviors for their children. This study aimed to develop and test an innovative 10-week worksite physical activity intervention integrated into the work flow of hospital-based nurses who were mothers. Three volunteer adult medical-surgical nursing units participated as intervention units. Fifty-eight nurses (30 intervention and 28 control) provided baseline and post-intervention repeated measurements of physical activity (steps) and body composition. Intervention participants provided post-intervention focus group feedback. For both groups, daily steps averaged more than 12,400 at baseline and post-intervention. No significant effects were found for physical activity; significant effects were found for fat mass, fat index, and percent fat (p < .03). Focus group findings supported the intervention and other data collected. The worksite holds promise for targeting the health of working mothers. Future research is warranted with a larger sample, longer intervention, and additional measures.

The feasibility of ambulatory screen time in children.

PURPOSE: A walking media station was developed, which enables normally seated screen activities to be conducted whilst walking. This study tests feasibility of the walking media station and provides preliminary evidence of the acceptability of the device in the home environment. METHODS: Twenty-nine healthy children (mean age 9.6 years) participated in the testing of the newly developed walking media station in the laboratory and in the home environment. RESULTS: Steady gait walking at 1 km.hr(-1) was achieved by all the children in less than 1 minute. There was no significant difference between computer game score during seated and walking play modes and no increase in energy cost when computer game play was added to walking (p>0.05). When given the choice in the home, all chose to use the walking media station rather than play seated. When asked: "If this unit were yours to keep forever, would you play video games on it?" all responded affirmatively. CONCLUSION: These data demonstrate that when given a walking media station, children can and will use it. Re-engineering regular walking into otherwise seated gaming minimizes disruption to normal routines and provides an innovative and creative opportunity for further investigation into the sustainability and clinical outcomes of reducing sitting time and increasing physical activity.

The role of free-living daily walking in human weight gain and obesity.

OBJECTIVE: Diminished daily physical activity explains, in part, why obesity and diabetes have become worldwide epidemics. In particular, chair use has replaced ambulation, so that obese individuals tend to sit for approximately 2.5 h/day more than lean counterparts. Here, we address the hypotheses that free-living daily walking distance is decreased in obesity compared with lean subjects and that experimental weight gain precipitates decreased daily walking. RESEARCH DESIGN AND METHODS: During weight-maintenance feeding, we measured free-living walking using a validated system that captures locomotion and body movement for 10 days in 22 healthy lean and obese sedentary individuals. These measurements were then repeated after the lean and obese subjects were overfed by 1,000 kcal/day for 8 weeks. RESULTS: We found that free-living walking comprises many (approximately 47) short-duration (<15 min), low-velocity ( approximately 1 mph) walking bouts. Lean subjects walked 3.5 miles/day more than obese subjects (n = 10, 10.3 +/- 2.5 vs. n = 12, 6.7 +/- 1.8 miles/day; P = 0.0009). With overfeeding, walking distance decreased by 1.5 miles/day compared with baseline values (-1.5 +/- 1.7 miles/day; P = 0.0005). The decrease in walking that accompanied overfeeding occurred to a similar degree in the lean (-1.4 +/- 1.9 miles/day; P = 0.04) and obese (-1.6 +/- 1.7 miles/day; P = 0.008) subjects. CONCLUSIONS: Walking is decreased in obesity and declines with weight gain. This may represent a continuum whereby progressive increases in weight are associated with progressive decreases in walking distance. By identifying walking as pivotal in weight gain and obesity, we hope to add credence to an argument for an ambulatory future.

Nonexercise movement in elderly compared with young people.

The association between free-living daily activity and aging is unclear because nonexercise movement and its energetic equivalent, nonexercise activity thermogenesis, have not been exhaustively studied in the elderly. We wanted to address the hypothesis that free-living nonexercise movement is lower in older individuals compared with younger controls matched for lean body mass. Ten lean, healthy, sedentary elderly and 10 young subjects matched for lean body mass underwent measurements of nonexercise movement and body posture over 10 days using sensitive, validated technology. In addition, energy expenditure was assessed using doubly labeled water and indirect calorimetry. Total nonexercise movement (acceleration arbitrary units), standing time, and standing acceleration were significantly lower in the elderly subjects; this was specifically because the elderly walked less distance per day despite having a similar number of walking bouts per day compared with the young individuals. The energetic cost of basal metabolic rate, thermic effect of food, total daily energy expenditure, and nonexercise activity thermogenesis were not different between the elderly and young groups. Thus, the energetic cost of walking in the elderly may be greater than in the young. Lean, healthy elderly individuals may have a biological drive to be less active than the young.

Laboratory measurement of posture allocation and physical activity in children.

PURPOSE: The purpose of this study was to validate the combined use of inclinometers and accelerometers to measure body posture and movement in children in a laboratory setting. METHODS: We performed two separate experiments. In the first experiment, we tested the hypothesis that four inclinometers (tilt sensors) could be used to capture body posture in children. We observed and recorded body posture in eight healthy children (mean +/- SD; body mass index (BMI), 18 +/- 3 kg x m(-2)) on 2880 occasions and compared these records with the inclinometer data. In the second experiment, the hypothesis was that two inclinometers could be used to determine whether 18 children (BMI, 21 +/- 5 kg x m(-2)) were sedentary. We observed and recorded sedentariness (sitting/lying compared to standing) on 5575 occasions and compared these records with the inclinometer data. In both of these experiments, we also addressed the hypothesis that accelerometer output, when measured at varying velocities, correlated with walking energy expenditure. RESULTS: In experiment 1, body posture was correctly identified in 2880 out of 2880 inclinometer measurements. In experiment 2, sedentary behavior was correctly identified in 5575 out of 5575 occasions. For the entire group, acceleration and body weight correlated well with energy expenditure (r2 = 0.84). CONCLUSION: The inclinometer-accelerometer system that we tested can be used to measure body posture and movement. We can measure sedentary behavior using two inclinometers instead of four inclinometers. This monitoring system may be useful for measuring energy expenditure, body posture, and physical activity in children.

Precision and accuracy of an ankle-worn accelerometer-based pedometer in step counting and energy expenditure.

BACKGROUND: Walking is a widely used approach to increase physical activity levels in obese patients. In this paper, we investigate the precision and accuracy of an ankle-worn dual-axis accelerometer (Stepwatch) and investigate its potential application as a predictor of energy expenditure. METHODS: Twenty healthy subjects (10 lean, 10 obese) wore spring-levered (Accusplit), piezoelectric (Omron HF-100), and Stepwatch pedometers. Subjects walked on a treadmill at 1, 2, and 3 mph and in a hallway at 1 and 1.85 mph, during which energy expenditure was measured. RESULTS: The Stepwatch counted 99.7 +/- 0.67% (mean +/- SEM) of the manual counts. In comparison, the Omron pedometer counted 61 +/- 3.3% and the Accusplit counted 26 +/- 2.8% of the manual counts at 1 mph although all pedometers were accurate (> 98% of counts) at 3 mph. In repeated measures, the Stepwatch produced negligible variance (SD = 0.36) over all speed whereas the other pedometers showed a large amount of variance at all speed (SD = 4-13). Stepwatch counts were predictive of walking energy expenditure corrected by weight (r2 > 0.8). CONCLUSION: The counts from the Stepwatch were virtually identical to the manual counts from a trained investigator and provided a reliable predictor of walking energy expenditure.

Interindividual variation in posture allocation: possible role in human obesity.

Obesity occurs when energy intake exceeds energy expenditure. Humans expend energy through purposeful exercise and through changes in posture and movement that are associated with the routines of daily life [called nonexercise activity thermogenesis (NEAT)]. To examine NEAT's role in obesity, we recruited 10 lean and 10 mildly obese sedentary volunteers and measured their body postures and movements every half-second for 10 days. Obese individuals were seated, on average, 2 hours longer per day than lean individuals. Posture allocation did not change when the obese individuals lost weight or when lean individuals gained weight, suggesting that it is biologically determined. If obese individuals adopted the NEAT-enhanced behaviors of their lean counterparts, they might expend an additional 350 calories (kcal) per day.