The Effects of Experimental Manipulation of Sleep Duration on Neural Response to Food Cues.

Despite growing literature on neural food cue responsivity in obesity, little is known about how the brain processes food cues following partial sleep deprivation and whether short sleep leads to changes similar to those observed in obesity. We used functional magnetic resonance imaging (fMRI) to test the hypothesis that short sleep leads to increased reward-related and decreased inhibitory control-related processing of food cues.In a within-subject design, 30 participants (22 female, mean age = 36.7 standard deviation = 10.8 years, body mass index range 20.4-40.7) completed four nights of 6 hours/night time-in-bed (TIB; short sleep) and four nights of 9 hours/night TIB (long sleep) in random counterbalanced order in their home environments. Following each sleep condition, participants completed an fMRI scan while viewing food and nonfood images.A priori region of interest analyses revealed increased activity to food in short versus long sleep in regions of reward processing (eg, nucleus accumbens/putamen) and sensory/motor signaling (ie, right paracentral lobule, an effect that was most pronounced in obese individuals). Contrary to the hypothesis, whole brain analyses indicated greater food cue responsivity during short sleep in an inhibitory control region (right inferior frontal gyrus) and ventral medial prefrontal cortex, which has been implicated in reward coding and decision-making (false discovery rate corrected q = 0.05).These findings suggest that sleep restriction leads to both greater reward and control processing in response to food cues. Future research is needed to understand the dynamic functional connectivity between these regions during short sleep and whether the interplay between these neural processes determines if one succumbs to food temptation.

Exercise improves quality of life in bariatric surgery candidates: results from the Bari-Active trial.

OBJECTIVE: To examine the impact of a pre-bariatric surgery physical activity intervention (PAI), designed to increase bout-related (≥10 min) moderate to vigorous PA (MVPA), on health-related quality of life (HRQoL). METHODS: Analyses included 75 adult participants (86.7% female; BMI = 45.0 ± 6.5 kg m(-2)) who were randomly assigned to 6 weeks of PAI (n = 40) or standard pre-surgical care (SC; n = 35). PAI received 6 individual weekly counseling sessions to increase walking exercise. Participants wore an objective PA monitor for 7 days and completed the SF-36 Health Survey at baseline and post-intervention to evaluate bout-related MVPA and HRQoL changes, respectively. RESULTS: PAI increased bout-related MVPA from baseline to post-intervention (4.4 ± 5.5 to 21.0 ± 21.4 min day(-1)) versus no change (7.9 ± 16.6 to 7.6 ± 11.5 min day(-1)) for SC (P = 0.001). PAI reported greater improvements than SC on all SF-36 physical and mental scales (P < 0.05), except role-emotional. In PAI, better baseline scores on the physical function and general health scales predicted greater bout-related MVPA increases (P < 0.05), and greater bout-related MVPA increases were associated with greater post-intervention improvements on the physical function, bodily pain, and general health scales (P < 0.05). CONCLUSIONS: Increasing PA preoperatively improves physical and mental HRQoL in bariatric surgery candidates. Future studies should examine whether this effect improves surgical safety, weight loss outcomes, and postoperative HRQoL.

Bari-Active: a randomized controlled trial of a preoperative intervention to increase physical activity in bariatric surgery patients.

BACKGROUND: Habitual physical activity (PA) may help to optimize bariatric surgery outcomes; however, objective PA measures show that most patients have low PA preoperatively and make only modest PA changes postoperatively. Patients require additional support to adopt habitual PA. The objective of this study was to test the efficacy of a preoperative PA intervention (PAI) versus standard presurgical care (SC) for increasing daily moderate-to-vigorous PA (MVPA) in bariatric surgery patients. METHODS: Outcomes analysis included 75 participants (86.7% women; 46.0±8.9 years; body mass index [BMI]=45.0±6.5 kg/m2) who were randomly assigned preoperatively to 6 weeks of PAI (n=40) or SC (n=35). PAI received weekly individual face-to-face sessions with tailored instruction in behavioral strategies (e.g., self-monitoring, goal-setting) to increase home-based walking exercise. The primary outcome, pre- to postintervention change in daily bout-related (≥10 min bouts) and total (≥1 min bouts) MVPA minutes, was assessed objectively via a multisensor monitor worn for 7 days at baseline- and postintervention. RESULTS: Retention was 84% at the postintervention primary endpoint. In intent-to-treat analyses with baseline value carried forward for missing data and adjusted for baseline MVPA, PAI achieved a mean increase of 16.6±20.6 min/d in bout-related MVPA (baseline: 4.4±5.5 to postintervention: 21.0±21.4 min/d) compared to no change (-0.3±12.7 min/d; baseline: 7.9±16.6 to postintervention: 7.6±11.5 min/d) for SC (P=.001). Similarly, PAI achieved a mean increase of 21.0±26.9 min/d in total MVPA (baseline: 30.9±21.2 to postintervention: 51.9±30.0 min/d), whereas SC demonstrated no change (-0.1±16.3 min/d; baseline: 33.7±33.2 to postintervention: 33.6±28.5 minutes/d) (P=.001). CONCLUSION: With behavioral intervention, patients can significantly increase MVPA before bariatric surgery compared to SC. Future studies should determine whether preoperative increases in PA can be maintained postoperatively and contribute to improved surgical outcomes.

Failure to replicate depletion of self-control.

The limited resource or strength model of self-control posits that the use of self-regulatory resources leads to depletion and poorer performance on subsequent self-control tasks. We conducted four studies (two with community samples, two with young adult samples) utilizing a frequently used depletion procedure (crossing out letters protocol) and the two most frequently used dependent measures of self-control (handgrip perseverance and modified Stroop). In each study, participants completed a baseline self-control measure, a depletion or control task (randomized), and then the same measure of self-control a second time. There was no evidence for significant depletion effects in any of these four studies. The null results obtained in four attempts to replicate using strong methodological approaches may indicate that depletion has more limited effects than implied by prior publications. We encourage further efforts to replicate depletion (particularly among community samples) with full disclosure of positive and negative results.

B-MOBILE--a smartphone-based intervention to reduce sedentary time in overweight/obese individuals: a within-subjects experimental trial.

PURPOSE: Excessive sedentary time (SED) has been linked to obesity and other adverse health outcomes. However, few sedentary-reducing interventions exist and none have utilized smartphones to automate behavioral strategies to decrease SED. We tested a smartphone-based intervention to monitor and decrease SED in overweight/obese individuals, and compared 3 approaches to prompting physical activity (PA) breaks and delivering feedback on SED. DESIGN AND METHODS: Participants [N = 30; Age = 47.5(13.5) years; 83% female; Body Mass Index (BMI) = 36.2(7.5) kg/m2] wore the SenseWear Mini Armband (SWA) to objectively measure SED for 7 days at baseline. Participants were then presented with 3 smartphone-based PA break conditions in counterbalanced order: (1) 3-min break after 30 SED min; (2) 6-min break after 60 SED min; and (3) 12-min break after 120 SED min. Participants followed each condition for 7 days and wore the SWA throughout. RESULTS: All PA break conditions yielded significant decreases in SED and increases in light (LPA) and moderate-to-vigorous PA (MVPA) (p<0.005). Average % SED at baseline (72.2%) decreased by 5.9%, 5.6%, and 3.3% [i.e. by mean (95% CI) -47.2(-66.3, -28.2), -44.5(-65.2, -23.8), and -26.2(-40.7, -11.6) min/d] in the 3-, 6-, and 12-min conditions, respectively. Conversely, % LPA increased from 22.8% to 26.7%, 26.7%, and 24.7% [i.e. by 31.0(15.8, 46.2), 31.0(13.6, 48.4), and 15.3(3.9, 26.8) min/d], and % MVPA increased from 5.0% to 7.0%, 6.7%, and 6.3% (i.e. by 16.2(8.5, 24.0), 13.5(6.3, 20.6), and 10.8(4.2, 17.5) min/d] in the 3-, 6-, and 12-min conditions, respectively. Planned pairwise comparisons revealed the 3-min condition was superior to the 12-min condition in decreasing SED and increasing LPA (p<0.05). CONCLUSION: The smartphone-based intervention significantly reduced SED. Prompting frequent short activity breaks may be the most effective way to decrease SED and increase PA in overweight/obese individuals. Future investigations should determine whether these SED reductions can be maintained long-term. TRIAL REGISTRATION: ClinicalTrials.gov NCT01688804.

Randomized controlled trial of a comprehensive home environment-focused weight-loss program for adults.

OBJECTIVE: Behavioral weight-loss programs (BWL) provide limited instruction on how to change the environmental context of weight-regulating behaviors, perhaps contributing to regain. Drawing on social ecological models, this trial evaluated a comprehensive weight-loss program that targeted both an individual's behavior and his or her physical and social home environment. METHOD: Overweight and obese adults (N = 201; 48.9 ± 10.5 years; 78.1% women) were randomized to BWL or to BWL plus home-environment changes (BWL + H). Groups met weekly for 6 months and bimonthly for 12 months. BWL + H participants were given items to facilitate healthy choices in their homes (e.g., exercise equipment, portion plates) and attended treatment with a household partner. Weight loss at 6 and 18 months was the primary outcome. RESULTS: BWL + H changed many aspects of the home environment and produced better 6-month weight losses than BWL (p = .017). At 18 months, no weight-loss differences were observed (p = .19) and rates of regain were equivalent (p = .30). Treatment response was moderated by gender (6 months, p = .011; 18 months, p = .006). Women lost more weight in BWL + H than BWL at 6 and 18 months, whereas men in BWL lost more weight than those in BWL + H at 18 months. Partners, regardless of gender, lost more weight in BWL + H than BWL at both time points (ps < .0001). CONCLUSION: The home food and exercise environment is malleable and targeting this microenvironment appears to improve initial weight loss, and in women, 18-month outcomes. Research is needed to understand this gender difference and to develop home-focused strategies with more powerful and sustained weight-loss effects.

Physical activity and quality of life in severely obese individuals seeking bariatric surgery or lifestyle intervention.

BACKGROUND: Given that bariatric surgery (BS) and lifestyle intervention (LI) represent two vastly different approaches to treating severe obesity, there is growing interest in whether individuals who seek BS versus LI also differ on weight-related behaviors. In the present study, we compared BS- and LI-seekers on physical activity (PA) and sedentary behaviors (SB), and examined between-group differences in health-related quality of life (HRQoL), while controlling for PA. FINDINGS: A sample of 34 LI-seekers were matched with 34 BS-seekers on gender, age, BMI, and PA monitor-daily wear time (age: 42.1±10.0 years; BMI: 45.6±6.5 kg/m2). PA and SB were assessed over a 7-day period via the SenseWear Armband (SWA). HRQoL was measured using the SF-36, with scores standardized to a population normal distribution (M=50, SD=10). Participants wore the SWA for 13.7±1.6 h/day. BS-seekers did not differ from LI-seekers on average min/d over the wear period spent in SB (641±117.1 vs. 638.4±133.4, p=0.62) or light (136.4±76.1 vs. 145.5±72.5, p=0.59) and moderate-to-vigorous (>1-min bouts=36.4±26.2 vs. 40.2±31.3, p=0.59; ≥10-min bouts=5.7±8.3 vs. 10.2±17.0, p=0.17) PA. BS-seekers reported significantly lower SF-36 physical functioning (42.4±10.9 vs. 49.0±6.8, p=0.004) and physical component summary (43.9±10.1 vs. 48.9±7.0) scores versus LI-seekers. BS-seeker group status was related to lower physical functioning (ß=0.30, p=0.009), independent of gender, age, BMI, and daily PA. CONCLUSIONS: Findings suggest that seeking BS versus LI is not related to patterns of PA or SB, and that lower subjective physical functioning is not associated with lower overall PA levels in BS-seekers.

Comparison of two objective monitors for assessing physical activity and sedentary behaviors in bariatric surgery patients.

BACKGROUND: Objective quantification of physical activity (PA) is needed to understand PA and sedentary behaviors in bariatric surgery patients, yet it is unclear whether PA estimates produced by different monitors are comparable and can be interpreted similarly across studies. METHODS: We compared PA estimates from the Stayhealthy RT3 triaxial accelerometer (RT3) and the Sensewear Pro(2) Armband (SWA) at both the group and individual participant level. Bariatric surgery candidates were instructed to wear the RT3 and SWA during waking hours for 7 days. Participants meeting valid wear time requirements (≥4 days of ≥8 h/day) for both monitors were included in the analyses. Time spent in sedentary (<1.5 METs), light (1.5-2.9 METs), moderate-to-vigorous (MVPA; ≥3.0 METs), and total PA (TPA; ≥1.5 METs) according to each monitor was compared. RESULTS: Fifty-five participants (BMI 48.4 ± 8.2 kg/m(2)) met wear time requirements. Daily time spent in sedentary (RT3 582.9 ± 94.3; SWA 602.3 ± 128.6 min), light (RT3 131.9 ± 60.0; SWA 120.6 ± 65.7 min), MVPA (RT3 25.9 ± 20.9; SWA 29.9 ± 19.5 min), and TPA (RT3 157.8 ± 74.5; SWA 150.6 ± 80.7 min) was similar between monitors (p > 0.05). While the average difference in TPA between the two monitors at the group level was 7.2 ± 64.2 min; the average difference between the two monitors for each participant was 45.6 ± 45.4 min. At the group level, the RT3 and SWA provide similar estimates of PA and sedentary behaviors; however, concordance between monitors may be compromised at the individual level. CONCLUSIONS: Findings related to PA and sedentary behaviors at the group level can be interpreted similarly across studies when either monitor is used.