BackgroundAlthough designed as a consumer product to help motivate individuals to be physically active, Fitbit activity trackers are becoming increasingly popular as measurement tools in physical activity and health promotion research and are also commonly used to inform health care decisions.ObjectiveThe objective of this review was to systematically evaluate and report measurement accuracy for Fitbit activity trackers in controlled and free-living settings.MethodsWe conducted electronic searches using PubMed, EMBASE, CINAHL, and SPORTDiscus databases with a supplementary Google Scholar search. We considered original research published in English comparing Fitbit versus a reference- or research-standard criterion in healthy adults and those living with any health condition or disability. We assessed risk of bias using a modification of the Consensus-Based Standards for the Selection of Health Status Measurement Instruments. We explored measurement accuracy for steps, energy expenditure, sleep, time in activity, and distance using group percentage differences as the common rubric for error comparisons. We conducted descriptive analyses for frequency of accuracy comparisons within a ±3% error in controlled and ±10% error in free-living settings and assessed for potential bias of over- or underestimation. We secondarily explored how variations in body placement, ambulation speed, or type of activity influenced accuracy.ResultsWe included 67 studies. Consistent evidence indicated that Fitbit devices were likely to meet acceptable accuracy for step count approximately half the time, with a tendency to underestimate steps in controlled testing and overestimate steps in free-living settings. Findings also suggested a greater tendency to provide accurate measures for steps during normal or self-paced walking with torso placement, during jogging with wrist placement, and during slow or very slow walking with ankle placement in adults with no mobility limitations. Consistent evidence indicated that Fitbit devices were unlikely to provide accurate measures for energy expenditure in any testing condition. Evidence from a few studies also suggested that, compared with research-grade accelerometers, Fitbit devices may provide similar measures for time in bed and time sleeping, while likely markedly overestimating time spent in higher-intensity activities and underestimating distance during faster-paced ambulation. However, further accuracy studies are warranted. Our point estimations for mean or median percentage error gave equal weighting to all accuracy comparisons, possibly misrepresenting the true point estimate for measurement bias for some of the testing conditions we examined.ConclusionsOther than for measures of steps in adults with no limitations in mobility, discretion should be used when considering the use of Fitbit devices as an outcome measurement tool in research or to inform health care decisions, as there are seemingly a limited number of situations where the device is likely to provide accurate measurement.

BackgroundPatient engagement in research (PEIR) is promoted to improve the relevance and quality of health research, but has little conceptualization derived from empirical data.ObjectiveTo address this issue, we sought to develop an empirically based conceptual framework for meaningful PEIR founded on a patient perspective.MethodsWe conducted a qualitative secondary analysis of in‐depth interviews with 18 patient research partners from a research centre‐affiliated patient advisory board. Data analysis involved three phases: identifying the themes, developing a framework and confirming the framework. We coded and organized the data, and abstracted, illustrated, described and explored the emergent themes using thematic analysis. Directed content analysis was conducted to derive concepts from 18 publications related to PEIR to supplement, confirm or refute, and extend the emergent conceptual framework. The framework was reviewed by four patient research partners on our research team.ResultsParticipants’ experiences of working with researchers were generally positive. Eight themes emerged: procedural requirements, convenience, contributions, support, team interaction, research environment, feel valued and benefits. These themes were interconnected and formed a conceptual framework to explain the phenomenon of meaningful PEIR from a patient perspective. This framework, the PEIR Framework, was endorsed by the patient research partners on our team.ConclusionsThe PEIR Framework provides guidance on aspects of PEIR to address for meaningful PEIR. It could be particularly useful when patient‐researcher partnerships are led by researchers with little experience of engaging patients in research.

ObjectiveThere is growing emphasis on health care organizations to ensure that lay people are meaningfully engaged as partners on research teams. Our aim was to explore the perspectives of patients, family members and informal caregivers who have been involved on health care research teams in Canada and elicit their recommendations for meaningful engagement.MethodsWe conducted a qualitative study guided by thematic analysis of transcripts of focus groups and interviews of 19 experienced patient research partners in Canada.ResultsWe identified four main themes: research environment, expectations, support and value, which highlight participants’ combined perspectives on important factors to ensure their engagement in research is meaningful.ConclusionsOur findings add to the evolving evidence base on the perspectives of lay people involved in health care research and their recommendations for research leaders on meaningful engagement. Our study suggests that research leaders should provide a welcoming research environment, outline appropriate expectations for patient research partners on research teams, support patient research partners’ engagement in projects and recognize the value patient research partners bring to health research.

ObjectivesTo develop and examine the content and face validity of the Patient Engagement In Research Scale (PEIRS) for assessing the quality of patient engagement in research projects from a patient partner perspective.MethodsOur team of researchers and patient partners conducted a mixed qualitative and quantitative study in three phases. Participants were English-speaking adult patients (including informal caregivers, family members, and friends) with varying experiences as partners in research projects in Canada. 1) Questionnaire items were generated following thematic analysis of in-depth interviews and published literature. 2) A three-round e-Delphi survey process via email correspondence was undertaken to refine and select the items for a provisional PEIRS. 3) Two rounds of cognitive interviewing elicited participants’ understanding and opinions of each item and the structure of the PEIRS.ResultsOne hundred and twenty items were generated from 18 interviews and organized across eight themes of meaningful engagement of patients in health research to form an initial questionnaire. The e-Delphi survey and cognitive interviewing each included 12 participants with a range of self-reported diseases, health-related conditions, and use of healthcare services. The e-Delphi survey yielded a 43-item provisional PEIRS. The PEIRS was then reduced to 37 items organized across seven themes after 1) refinement of problems in its instructions and items, and 2) the combining of two themes into one.ConclusionsWe developed a 37-item self-reported questionnaire that has demonstrated preliminary content and face validity for assessing the quality of patient engagement in research.

Six weeks (3 times/wk) of sprint-interval training (SIT) or continuous endurance training (CET) promote body-fat losses despite a substantially lower training volume with SIT. In an attempt to explain these findings, the authors quantified VO₂ during and after (24 h) sprint-interval exercise (SIE; 2 min exercise) vs. continuous endurance exercise (CEE; 30 min exercise). VO₂ was measured in male students (n = 8) 8 times over 24 hr under 3 treatments (SIE, CEE, and control [CTRL, no exercise]). Diet was controlled. VO₂ was 150% greater (p < .01) during CEE vs. SIE (87.6 ± 13.1 vs. 35.1 ± 4.4 L O₂; M ± SD). The observed small difference between average exercise heart rates with CEE (157 ± 10 beats/min) and SIE (149 ± 6 beats/min) approached significance (p = .06), as did the difference in peak heart rates during CEE (166 ± 10 beats/min) and SIE (173 ± 6 beats/min; p = .14). Total O₂ consumed over 8 hr with CEE (263.3 ± 30.2 L) was greater (p < .01) than both SIE (224.2 ± 15.3 L; p < .001) and CTRL (163.5 ± 16.1 L; p < .001). Total O₂ with SIE was also increased over CTRL (p < .001). At 24 hr, both exercise treatments were increased (p < .001) vs. CTRL (CEE = 500.2 ± 49.2; SIE = 498.0 ± 29.4; CTRL = 400.2 ± 44.6), but there was no difference between CEE and SIE (p = .99). Despite large differences in exercise VO₂, the protracted effects of SIE result in a similar total VO₂ over 24 hr vs. CEE, indicating that the significant body-fat losses observed previously with SIT are partially due to increases in metabolism postexercise.

We tested the hypothesis that diabetes impairs myocardial glucose uptake and pyruvate oxidation under normal conditions and during a dobutamine-induced increase in work. We also tested the hypothesis that an increase in work would result in a decrease in the levels of malonyl CoA, a potent inhibitor of carnitine palmitoyltransferase I (CPT I). Streptozotocin-diabetic micropigs were compared with a nondiabetic control group (n = 8 per group). Triglyceride emulsion, glucose, and somatostatin were infused into the nondiabetic group to create an acute diabetic-like state. In accord with our hypothesis, malonyl CoA decreased significantly with dobutamine in both groups, providing a possible mechanism for increased fatty acid oxidation through relieved inhibition on CPT I. In the absence of dobutamine, glucose uptake and tracer-measured lactate uptake were decreased by 57 and 80%, respectively, in the diabetic group. Dobutamine infusion resulted in similar increases in cardiac contractility, oxygen consumption, and glucose uptake in both groups despite reductions of 50-65% in GLUT-4 and GLUT-1 protein in the diabetic group. Diabetic animals possessed a defect in myocardial pyruvate oxidation, as reflected in increased lactate production, and depressed lactate uptake and pyruvate dehydrogenase activity under control and dobutamine conditions. In conclusion, the major derangement in carbohydrate metabolism in diabetic myocardium was not in glycolysis but, rather, in pyruvate oxidation.

Data on whether sprint interval training (SIT) (repeated supermaximal intensity, short-duration exercise) affects body composition are limited, and the data that are available suggest that men respond more favourably than do women. Moreover, most SIT data involve cycling exercise, and running may differ because of the larger muscle mass involved. Further, running is a more universal exercise type. This study assessed whether running SIT can alter body composition (air displacement plethysmography), waist circumference, maximal oxygen consumption, peak running speed, and (or) the blood lipid profile. Fifteen recreationally active women (age, 22.9 ± 3.6 years; height, 163.9 ± 5.1 cm; mass, 60.8 ± 5.2 kg) completed 6 weeks of running SIT (4 to 6, 30-s "all-out" sprints on a self-propelled treadmill separated by 4 min of rest performed 3 times per week). Training decreased body fat mass by 8.0% (15.1 ± 3.6 to 13.9 ± 3.4 kg, P = 0.002) and waist circumference by 3.5% (80.1 ± 4.2 to 77.3 ± 4.4 cm, P = 0.048), whereas it increased fat-free mass by 1.3% (45.7 ± 3.5 to 46.3 ± 2.9 kg, P = 0.05), maximal oxygen consumption by 8.7% (46 ± 5 to 50 ± 6 mL/(kg·min), P = 0.004), and peak running speed by 4.8% (16.6 ± 1.7 to 17.4 ± 1.4 km/h, P = 0.026). There were no differences in food intake assessed by 3-day food records (P > 0.329) or in blood lipids (P > 0.595), except for a slight decrease in high-density lipoprotein concentration (1.34 ± 0.28 to 1.24 ± 0.24 mmol/L, P = 0.034). Running SIT is a time-efficient strategy for decreasing body fat while increasing aerobic capacity, peak running speed, and fat-free mass in healthy young women.

(1) Malonyl-CoA is thought to play a signalling role in fuel-selection in cardiac muscle, but the rate at which the concentration of this potential signal can be changed has not previously been investigated. (2) Rapid changes in cellular malonyl-CoA could be observed when rat cardiac myocytes were incubated in glucose-free medium followed by re-addition of 5 mM glucose, or when cells were transferred from a medium containing glucose to a glucose-free medium. On addition of glucose, malonyl-CoA increased by 62% to a new steady-state level, at a rate of at least 0.4 nmol/g dry wt. per min. The half-time of this change was less than 3 min. After removal of glucose the malonyl-CoA content was estimated to decline by 0.43-0.55 nmol/g dry wt. per min. (3) Malonyl-CoA decarboxylase (MDC) is a possible route for disposal of malonyl-CoA. No evidence was obtained for a cytosolic activity of MDC in rat heart where most of the activity was found in the mitochondrial fraction. MDC in the mitochondrial matrix was not accessible to extramitochondrial malonyl-CoA. However, approx. 16% of the MDC activity in mitochondria was overt, in a manner that could not be explained by mitochondrial leakage. It is suggested that this, as yet uncharacterized, overt MDC activity could provide a route for disposal of cytosolic malonyl-CoA in the heart. (4) No activity of the condensing enzyme for the fatty acid elongation system could be detected in any heart subcellular fraction using two assay systems. A previous suggestion [Awan and Saggerson (1993) Biochem. J. 295, 61-66] that this could provide a route for disposal of cytosolic malonyl-CoA in heart should therefore be abandoned.