PURPOSE and METHODS Though evidence is accumulating that sedentary behavior (SB), independent of moderate-to-vigorous intensity physical activity (MVPA), is associated with cardiometabolic and aging outcomes in adults, several gaps present opportunities for future research. This paper reports on the ‘Research Evidence on Sedentary Behavior’ session of the Sedentary Behavior: Identifying Research Priorities workshop, sponsored by the National Heart, Lung and Blood Institute and the National Institute on Aging, which aimed to identify priorities in SB research. RESULTS and CONCLUSIONS A consensus definition of SB has not yet been established, though agreement exists that SB is not simply all behaviors other than MVPA. The two most common definitions are: one based solely on intensity (<1.5 metabolic equivalents (METS)) and another which combines low intensity (≤1.5 METS) with a seated or reclining posture. Thus, for the definition of SB, evaluation of whether or not to include a postural component is a research priority. SB assessment methodologies include self-report and objective measurement, each offering distinct information. Therefore, evaluation, standardization, and comparison across self-report and objective assessment methods are needed. Specific priorities include the development and validation of novel devices capable of assessing posture and standardization of research practices for SB assessment by accelerometry. The prospective evidence that SB relates to health outcomes is limited in that SB is almost exclusively measured by self-report. The lack of longitudinal studies with objectively-measured SB was recognized as a major research gap, making examination of the association between objectively-measured SB and adverse health outcomes in longitudinal studies a research priority. Specifically, studies with repeated measures of SB, evaluating dose-response relationships, with inclusion of more diverse populations are needed.

BackgroundDespite growing evidence on benefits of increased physical activity in hemodialysis (HD) patients and safety of intra-dialytic exercise, it is not part of standard clinical care, resulting in a missed opportunity to improve clinical outcomes in these patients. To develop a successful exercise program for HD patients, it is critical to understand patients’, staff and nephrologists’ knowledge, barriers, motivators and preferences for patient exercise.MethodsIn-depth interviews were conducted with a purposive sample of HD patients, staff and nephrologists from 4 dialysis units. The data collection, analysis and interpretation followed Criteria for Reporting Qualitative Research guidelines. Using grounded theory, emergent themes were identified, discussed and organized into major themes and subthemes.ResultsWe interviewed 16 in-center HD patients (mean age 60 years, 50% females, 63% blacks), 14 dialysis staff members (6 nurses, 3 technicians, 2 dietitians, 1 social worker, 2 unit administrators) and 6 nephrologists (50% females, 50% in private practice). Although majority of the participants viewed exercise as beneficial for overall health, most patients failed to recognize potential mental health benefits. Most commonly reported barriers to exercise were dialysis-related fatigue, comorbid health conditions and lack of motivation. Specifically for intra-dialytic exercise, participants expressed concern over safety and type of exercise, impact on staff workload and resistance to changing dialysis routine. One of the most important motivators identified was support from friends, family and health care providers. Specific recommendations for an intra-dialytic exercise program included building a culture of exercise in the dialysis unit, and providing an individualized engaging program that incorporates education and incentives for exercising.ConclusionPatients, staff and nephrologists perceive a number of barriers to exercise, some of which may be modifiable. Participants desired an individualized intra-dialytic exercise program which incorporates education and motivation, and they provided a number of recommendations that should be considered when implementing such a program.

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Eight years of intensive lifestyle intervention did not alter cognitive function in obese adults with type 2 diabetes; however, there was evidence for benefit among overweight but not obese individuals. Changes in cognition were not assessed in this cross-sectional study.

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Intentional weight loss is an important treatment option for overweight persons with type 2 diabetes mellitus (DM), but the effects on long term fracture risk are not known. The purpose of this Look AHEAD analysis was to evaluate whether long term intentional weight loss would increase fracture risk in overweight or obese persons with DM. Look AHEAD is a multicenter, randomized clinical trial. Recruitment began in August 2001 and follow-up continued for a median of 11.3 years at 16 academic centers. 5145 persons aged 45 – 76 with DM were randomized to either an intensive lifestyle intervention (ILI) with reduced calorie consumption and increased physical activity designed to achieve and maintain ≥7% weight loss or to diabetes support and education intervention (DSE). Incident fractures were ascertained every 6 months by self-report and confirmed with central adjudication of medical records. The baseline mean age of participants was 59 years, 60% were women, 63% were Caucasian, and the mean BMI was 36 kg/m2. Weight loss over the intervention period (median 9.6 years) was 6.0% in ILI and 3.5% in DSE. 731 participants had a confirmed incident fracture (358 in DSE v. 373 in ILI). There were no statistically significant differences in incident total or hip fracture rates between the ILI and DSE groups. However, compared to the DSE group, the ILI group had a statistically significant 39% increased risk of a frailty fracture (HR = 1.39, 95% CI 1.02, 1.89). An intensive lifestyle intervention resulting in long term weight loss in overweight/obese adults with DM was not associated with an overall increased risk of incident fracture but may be associated with an increased risk of frailty fracture. When intentional weight loss is planned, consideration of bone preservation and fracture prevention is warranted.

Interrupting prolonged sitting with light activity breaks, such as short walks, improves cardiometabolic outcomes, yet less is known about the impact of resistance exercise breaks. This study examined the effects of hourly, guidelines-based simple resistance exercise breaks on acute cardiometabolic health outcomes over a simulated work period. Fourteen adults (age: 53.4 ± 9.5 years, body mass index: 30.9 ± 4.8 kg/m2) completed 2 randomized 4-h conditions: prolonged sitting (SIT) and hourly resistance exercise breaks (REX). Glucose, triglycerides, blood pressure, and heart rate were measured at baseline and then hourly. Pulse wave velocity (PWV) was measured before and after each condition. Linear mixed models evaluated overall condition effects and differences at each hour. Cohen’s d estimated magnitude of effects. Four-hour glucose area under the curve (AUC) did not differ by condition (REX vs. SIT: β = –0.35 mmol/L, p = 0.278, d = 0.51). However, an attenuation of postprandial glucose at 1 h (β = –0.69 mg/dL, p = 0.004, d = 1.02) in REX compared with SIT was observed. Triglyceride AUC, mean blood pressure, and PWV did not differ significantly between REX and SIT overall or any time point (all p > 0.05). Heart rate was higher across the experimental period in REX versus SIT (β = 3.3 bpm, p < 0.001, d = 0.35) and individual time points (β ≥ 3.2 bpm, p ≤ 0.044, d ≥ 0.34). Resistance exercise breaks can potentially improve 1-h postprandial glucose, but may not acutely benefit other cardiometabolic outcomes. Future studies employing guidelines-based resistance exercises to interrupt prolonged sitting with a larger sample and longer follow-up are warranted.

Objective: The aim of this study is to evaluate accuracy of research activity monitors in measuring steps in older adults with a range of walking abilities. Method: Participants completed an initial assessment of gait speed. The accuracy of each monitor to record 100 steps was assessed across two walking trials. Results: In all, 43 older adults (age 87 ± 5.7 years, 81.4% female) participated. Overall, the StepWatch had the highest accuracy (99.0% ± 1.5%), followed by the ActivPAL (93.7% ± 11.1%) and the Actigraph (51.4% ± 35.7%). The accuracy of the Actigraph and ActivPAL varied according to assistive device use, and the accuracy of all three monitors differed by gait speed category (all p < .05). StepWatch was highly accurate (⩾97.7) across all conditions. Discussion: The StepWatch and ActivPAL monitor were reasonably accurate in measuring steps in older adults who walk slowly and use an assistive device. The Actigraph significantly undercounted steps in those who walk slow or use an assistive device. Researchers should consider gait speed and the use of assistive devices when selecting an activity monitor.