Background: The global rise in overweight, obesity, impaired glucose regulation, and type 2 diabetes mellitus has major consequences for health and quality of life. Tackling this epidemic is complex and influenced by genetic, social, and environmental factors, as well as healthcare accessibility and lifestyle behaviors. An important aspect of lifestyle behavior is understanding how the time we spend sleeping, being sedentary, and moving each day affects our health. For a long time, these behaviors were studied separately, but recent insights show that they are inherently interconnected. Spending more time on one behavior automatically means spending less time on another, which has led to the research field of 24-hour movement behavior. This field examines all behaviors within a single day in relation to one another and forms the basis of the 24-hour guidelines, which recommend at least 150 minutes of moderate-to-vigorous activity per week, daily light activity, a maximum of eight hours of sedentary behavior, and seven to nine hours of sleep. Although these guidelines are rarely met, very little is known about 24-hour movement behavior in adults with chronic metabolic conditions. Research in the general population shows that shifting time from sleep, sedentary behavior, or light activity to moderate-to-vigorous physical activity leads to significant health benefits. It is plausible that these effects are equally strong—or stronger—in people with chronic metabolic conditions, but this has barely been studied.

Aim: The aim of this doctoral research was to investigate 24-hour movement behavior in adults with chronic metabolic conditions, including overweight, obesity, impaired glucose regulation, and type 2 diabetes mellitus, with a focus on (1) methodological advancements in the collection and analysis of 24-hour movement behavior, (2) understanding the clinical relevance of 24-hour movement behavior, (3) comparing 24-hour movement behavior between populations with chronic metabolic conditions as well as the trends over time, and (4) identifying explanatory variables of 24-hour movement behavior in these populations.

Results and conclusion: This doctoral research demonstrates that measuring complete 24-hour movement behavior is complex: different measurement and analysis methods of 24-hour movement behaviors yield divergent outcomes and influence conclusions about health. Uniform methods are therefore essential. Furthermore, adults with chronic metabolic conditions were found to engage in more sedentary behavior and less light and moderate-to-vigorous physical activity than adults without such conditions. Over a nine-year period, individuals with poorer glucose regulation—including those with (or later developing) type 2 diabetes mellitus—showed a clear shift toward more sedentary behavior and a decrease in both light and moderate-to-vigorous physical activity. Additionally, beneficial health effects were observed for BMI, waist circumference, triglycerides, and HDL cholesterol when time was theoretically shifted from sedentary behavior to more physical activity, or from sleep to more physical activity (only when the sleep duration was not already too short). This underscores the need to develop interventions that optimize 24-hour movement behavior. However to develop effective interventions, insight into the determinants of this behavior is essential. This research found that in adults with chronic metabolic conditions, these  behavioral correlates originated from various levels of the socio-ecological model, highlighting the multilevel complexity of behavior change. They included correlates such as intrinsic motivation, perceived barriers to being more active, and self-efficacy (intrapersonal), social support (interpersonal), and the availability of facilities and an activity-friendly environment (environmental level). Movement-care professionals, such as exercise-referral coaches, can play a key role by not only promoting isolated behaviors but by identifying opportunities to optimize clients’ entire daily routines.