Seth A. Creasy

Reducing Sedentary Behavior Versus Increasing Moderate-to-Vigorous Intensity Physical Activity in Older Adults: A 12-Week Randomized, Clinical Trial.

Objective: To compare the effects of behavioral interventions targeting decreased sedentary behavior versus increased moderate-to-vigorous intensity physical activity (MVPA) in older adults. Method: Inactive older adults (N = 38, 68 ± 7 years old, 71% female) were randomized to 12-week interventions targeting decreased sedentary behavior (Sit Less) or increased MVPA (Get Active). The SenseWear armband was used to objectively assess activity in real time. Assessments included a blinded armband, the Community Health Activites Model Program for Senior (CHAMPS) questionnaire, 400-meter walk, and the Short Physical Performance Battery (SPPB). Results: Objectively measured MVPA increased in Get Active (75 ± 22 min/week, p < .001); self-reported MVPA increased in both groups (p < .05). Sedentary behavior did not change in either group (all p > .05). Only the Sit Less group improved the SPPB score (0.5 ± 0.3, p = .046). Discussion: Targeting reduced sedentary behavior had a greater effect on physical function among inactive but high functioning older adults over 12 weeks. Future studies of longer duration and combining increased MVPA with reduced sedentary behavior are needed.

Energy Expenditure During Acute Periods of Sitting, Standing, and Walking

BACKGROUND Identifying strategies to increase energy expenditure (EE) may help combat the harmful effects of sedentary behavior. This study examined EE during sitting, standing, and walking. METHODS Participants (N = 74) were randomized to 2 of the following activities: sitting using a laptop computer (SIT-C), sitting watching television (SIT-T), standing watching television (STAND), and walking at a self-selected pace ≤3.0 (mph) (WALK). Each activity lasted 15 minutes with a 3-minute transition period between activities. The experimental conditions were: SIT-C to STAND (N = 18), SIT-T to WALK (N = 18), STAND to SIT-C (N = 20), and WALK to SIT-T (N = 18). EE was measured using indirect calorimetry. RESULTS Based on the first activity performed, EE during WALK (55.92 ± 14.19 kcal) was significantly greater than SIT-C (19.63 ± 6.90 kcal), SIT-T (18.66 ± 4.01 kcal), and STAND (21.92 ± 5.08 kcal) (P < .001). Cumulative EE in SIT-T to WALK (74.50 ± 17.88 kcal) and WALK to SIT-T (82.72 ± 21.70 kcal) was significantly greater than EE in SIT-C to STAND (45.38 ± 14.78 kcal) and STAND to SIT-C (45.64 ± 9.69 kcal) (P < .001). CONCLUSION Substituting periods of sitting or standing with walking significantly increases EE, but substituting periods of sitting with standing may not affect EE. Thus, the potential benefits of standing as opposed to sitting need further investigation beyond the role of EE.

Energy Expenditure in Vinyasa Yoga Versus Walking

BACKGROUND Whether the energy cost of vinyasa yoga meets the criteria for moderate-to-vigorous physical activity has not been established. PURPOSE To compare energy expenditure during acute bouts of vinyasa yoga and 2 walking protocols. METHODS Participants (20 males, 18 females) performed 60-minute sessions of vinyasa yoga (YOGA), treadmill walking at a self-selected brisk pace (SELF), and treadmill walking at a pace that matched the heart rate of the YOGA session (HR-Match). Energy expenditure was assessed via indirect calorimetry. RESULTS Energy expenditure was significantly lower in YOGA compared with HR-Match (difference = 79.5 ± 44.3 kcal; P < .001) and SELF (difference = 51.7 ± 62.6 kcal; P < .001), but not in SELF compared with HR-Match (difference = 27.8 ± 72.6 kcal; P = .054). A similar pattern was observed for metabolic equivalents (HR-Match = 4.7 ± 0.8, SELF = 4.4 ± 0.7, YOGA = 3.6 ± 0.6; P < .001). Analyses using only the initial 45 minutes from each of the sessions, which excluded the restorative component of YOGA, showed energy expenditure was significantly lower in YOGA compared with HR-Match (difference = 68.0 ± 40.1 kcal; P < .001) but not compared with SELF (difference = 15.1 ± 48.7 kcal; P = .189). CONCLUSIONS YOGA meets the criteria for moderate-intensity physical activity. Thus, YOGA may be a viable form of physical activity to achieve public health guidelines and to elicit health benefits.

Effects of supervised and unsupervised physical activity programmes for weight loss

Physical activity is important for weight management. However, it remains unclear what type of physical activity prescription/programme is optimal for increasing physical activity during a standard behavioural weight loss intervention. This study examined changes in physical activity after a 12‐week supervised programme prescribed in minutes per week (SUP‐PA), an unsupervised programme prescribed in minutes per week (UNSUP‐PA) and an unsupervised programme prescribed in steps per day (STEP).

Sedentary Behavior and Physical Activity are associated with Sleep Duration and Sleep Quality in Postmenopausal Women: 634 Board #3 May 30 3

biomarkers (total nitrate+nitrite, ET-1, ICAM-1 and VCAM-1) were measured. Sympathetic nervous activity was also estimated (peroneal microneurography and circulating catecholamines). Data were analysed using generalised linear mixed models controlling for age, sex, BMI, baseline values and treatment order, and are presented as marginal mean±SEM. RESULTS: Femoral artery FMD was impaired in the SIT condition, compared to SRA (5.1±0.5% vs 9.0±0.5%, respectively, p<0.05). Significantly higher circulating levels of the potent vasoconstrictor and pro-inflammatory mediator ET-1 (1.6±0.1 vs 1.4±0.1 pg/ml) and pro-atherogenic adhesion biomarker VCAM-1 (616±33 vs 564±26 ng/ml) were observed in SIT compared to SRA, respectively (p<0.05). There were no differences between conditions for any other outcomes. CONCLUSION: In overweight/obese adults, an acute bout of uninterrupted sitting impaired femoral artery endothelium-mediated vasodilation and increased circulating levels of pro-atherosclerotic biomarkers. Prolonged sitting may have implications for vascular function, leukocyte adhesion and atherogenesis in those at heightened risk of cardiometabolic disease.

Energy Expenditure During Acute Periods Of Sitting, Standing, And Walking: 608 Board #7 June 1, 1: 00 PM - 3: 00 PM.

Previous studies have shown individual differences in the energy intake (EI) response to exercise, but homeostatic or cognitive mechanisms underlying these differences are unclear, particularly in youth. Fat-free mass is a known predictor of daily EI in adolescents and adults, predominantly through its effects on resting metabolic rate and total energy expenditure. In addition, studies in adults have shown that increased perceived difficulty of exercise is associated with caloric over-compensation through greater EI. However, the influence of these biological and psychological factors in children is unknown. PURPOSE: To examine the predictors of post-exercise EI in children. METHODS: Healthy-weight children ages 9-12 years (n = 18) reported to the laboratory for 1 baseline and 2 experimental visits (EX = exercise, SED = sedentary) each separated by 1 week in a randomized crossover design. Percent body fat (bioelectrical impedance analysis), weight (kg), and height (m) were used to calculate fat-mass index (FMI) and fat-free mass index (FFMI; kg/m 2 ). On the EX day, children exercised at 70% estimated VO2peak for 30 minutes on a cycle ergometer and gave ratings of perceived exertion (RPE). Objective EI (kcal) was measured at identical meals on the EX and SED days: standard breakfast and ad libitum lunch, snack, and dinner. Paired t-tests, Pearson’s correlations, and multiple linear regressions were performed using SPSS. RESULTS: Total EI was not statistically different between the EX and SED days (t = 0.47, p = 0.64). However, FFMI was positively associated with EI on the EX day (r = 0.50, p < 0.05), but not the SED day (p = 0.25). RPE was also positively associated with EI on the EX day (r = 0.78, p < 0.01). Together, FFMI and RPE explained 71% of the variability in EI on the EX day (F(2,15) = 17.14, p < 0.01). CONCLUSIONS: Fat-free mass was associated with EI on the EX day but not the SED day, suggesting better homeostatic regulation of EI with imposed exercise. Despite experiencing the same 70% relative exercise intensity, children varied in their perceived difficulty of the exercise. Increased perceived difficulty predicted greater EI on the EX day. These findings demonstrate a role for both homeostatic and cognitive factors in post-exercise EI regulation in children.