Sedentary behaviors and physical activity habits independently affect fat oxidation in fasting conditions and capillary glucose levels after standardized glucose-rich meal in healthy females

Purpose: Sedentary behaviors and muscle inactivity are being growingly recognized as important risk factors for health, adjunctively and independently from a scarce physical activity (PA), although the metabolic mechanism underneath is barely clear. To explore the relation between sedentary behaviors (SBs) and metabolism, we measured the metabolic profile in fasting condition and after oral glucose overload in a group of women, along with objective monitoring of their PA/sedentary lifestyle habits. Subjects and methods: Thirteen women (age: 32.5 ± 16.1 years; BMI: 24.0 ± 3.3 kg/m2), recruited among university students and research staff, underwent indirect calorimetry to assess fat and carbohydrate contribution to energy metabolism, in fasting conditions and after a glucose-rich standard meal (about 45 g of glucose). Glucose concentration in capillary blood was determined in fasting state and 15 and 30 min after meal. Habitual PA and SBs in the previous week were continuously monitored with Actigraph accelerometers. Results: After adjustment for age, the contribution of fat oxidation to metabolic energy sources, normalized for fat-free mass, in fasting conditions was significantly correlated with time spent in sitting/lying position during wake hours (p < 0.001), independent from PA habits, whereas capillary blood peak and change of glucose concentration after the meal were significantly and inversely correlated with average daily moderate to vigorous PA (p = 0.025 and p = 0.019, respectively), independent from average daily sitting/lying time. Conclusions: Here, we report for the first time a direct effect of muscle inactivity on increased fat oxidation in fasting conditions, which can be hypothesized as a preliminary condition for the development of insulin resistance. We also report the direct independent effect of PA on the capacity to respond to a glycemic load, so that SBs and reduced PA appear to concur, although independently, to the increased health risk, as elsewhere observed on an epidemiological ground

A mobile phone intervention to improve obesity-related health behaviors of adolescents across Europe: An iterative co-design and feasibility study

Background:Promotion of physical activity, healthy eating, adequate sleep and reduced sedentary behavior in adolescents is a major priority globally given the current increase in population health challenges of non-communicable diseases and risk factors such as obesity. Adolescents are highly engaged with mobile technology, but the challenge is to engage them with mHealth technology. Recent innovations in mobile technology provide opportunities to promote a healthy lifestyle in adolescents. An increasingly utilized approach to facilitate increased engagement with mHealth technology is to involve potential users in the creation of the technology.Objective:To describe the process of and findings from co-designing and prototyping components of the PEGASO Fit for Future mHealth intervention for adolescents from different cultural backgrounds.Methods:Seventy-four adolescents aged 13-16 years from Spain, Italy and the United Kingdom participated in the co-design of the PEGASO Fit for Future technology. In three iterative cycles over 12 months, participants were involved in the co-design, refinement and feasibility testing of a system consisting of diverse mobile applications with a variety of functions and facilities to encourage healthy weight promoting behaviors. In the first iteration, participants attended a single workshop session and were presented with mock-ups or early-version prototypes of different apps for user requirements assessment and review. During the second iteration, prototypes of all apps were tested by participants for one week at home or school. In the third iteration, further developed prototypes were tested for two weeks. Participants’ use experience feedback and development ideas were collected from focus groups and completion of questionnaires.Results:For the PEGASO Fit for Future technology to be motivating and engaging, participants suggested that it should (i) allow personalization of the interface, (ii) have age-appropriate and easy to understand language (of icons, labels, instructions, notifications), (iii) provide easily accessible tutorials on how to use the app or navigate through a game, (iv) present a clear purpose and end goal, (v) have an appealing and self-explanatory reward systems, (vi) offer variation in gamified activities within apps and the serious game, and (vii) allow to seek peer-support and connect with peers for competitive activities within the technology.Conclusions:Incorporating adolescents’ preferences, the PEGASO Fit for Future technology combines the functions of a self-monitoring, entertainment, advisory, and social support tool. This was the first study demonstrating that it is possible to develop a complex smartphone-based technological system applying the principles of co-design to mHealth technology with adolescents across three countries. Findings of this study informed the development of an mHealth system for healthy weight promotion to be tested in a controlled multi-national pilot trial