Physical inactivity is one of the major contributing factors for the development of chronic diseases and highly correlated with increased all-cause mortality. In the last decade an exponential growth in research concerned with the study of sedentary behaviour and the potential for detrimental effects on health have been published. In this field increasing evidence suggests that prolonged periods of sedentary time, independent of the amount of physical activity, also increases the risk for the development of several chronic conditions and all-cause mortality. Here, sedentary behaviour is defined as "any waking behaviour, characterized by a low energy expenditure (≤1.5 METs), while being in a sitting or reclining posture". Interestingly, the advised moderate-to-vigorous bouts of exercise recommended by the various guidelines cannot compensate the negative impact on health risks arising from prolonged periods of sitting. In other words, it seems that people compensate their total amount of physical activity after exercise training by decreasing their physical activity levels throughout the rest of the day. Here, it appears that frequent, even low-intensity interruptions of periods of sitting are required for good cardiometabolic health. Therefore, not only physical activity but also prolonged sitting should be targeted to optimize cardiometabolic health. Nevertheless, a recent harmonized meta-syntheses indicated that the association between self-reported sitting with all-cause and cardiovascular disease mortality are only partially independent of physical activity, but were particularly evident in those who undertake insufficient physical activity (<150min/week). However, it is unclear whether high amounts of objectively measured physical activity attenuates or even eliminates the detrimental effects of prolonged sitting. In addition, it is still unclear whether high amounts of physical activity can preserve a healthy cardiometabolic risk profile, despite prolonged sitting. Therefore, in this study we want to investigate the association between sedentary behaviour, physical activity and cardiometabolic health in highly physically active adults.

Inclusion Criteria:

• Active individuals with at least 4 training hours per week

Exclusion Criteria:

• pregnancy
• Any known contradiction for physical activity
• Systolic blood pressure >160mmHg, diastolic blood pressure >100mmHg
• More than 20 alcohol consumptions per week
• Participants diagnosed with any known chronic disease

Active individuals with at least 4 training hours per week and between 18 and 45 years of age.