Explorative study to investigate effects of reduced sitting intervention on total sitting time

Over the last years, physical inactivity has been identified as the major cause
of death in Western society. Since exercise training does not improve fitness
and cardiovascular risk in all subjects or may not be feasible for all
patients, we have searched for alternatives to reduce physical inactivity.
Interestingly, a 2.8-year prospective study in 222,497 individuals found that
>11h of sitting/day is associated with 40% higher risk for all-cause mortality
compared to <4h sitting/day. Importantly, the detrimental impact of sitting
time is not altered after correcting for exercise training time. Therefore, the
benefits from *reduce sitting time* and exercise training seem independent from
each other, and seem to work via distinct protective pathways. Consequently,
prolonged sitting is a logical target to improve fitness and cardiovascular
risk factors via *reduce sitting time*. In this study, we will explore the
efficacy of a novel *reduce sitting time*-intervention to reduce total sitting
time per day and increasing sit to stand transitions. Understanding the ability
of this device for prolonged and sustainable changes in behaviour seems
prerequisite for subsequent effects on health outcomes.

In this study we examine the effect of a 4-week reduced sitting time
intervention on physical activity pattern (i.e. total sitting time per day as
primary parameter). As a secondary objective, we re-examine behavioural
patterns 4 weeks after the intervention to explore longer-term adherence to the
intervention.

Intervention pilot study

4 weeks reduced sitting intervention, adopting a widely adopted and
RIVM-approved intervention.

Subjects will wear a pedometer throughout the day in order to record physical
activity patterns. Based on established algorithms, this device enables the
identification of prolonged periods of sitting or physical inactivity, which
will lead to notification of the participant that she/he has to break up
his/her sitting behaviour. In addition, a widely used physical activity monitor
(i.e. Sensewear armband) will be worn to assess physical activity levels.6
Participants will report 3 times to the research centre (before, after and
4-weeks after the intervention) to measure physical activity patterns (to
examine the primary research question), but also cardiovascular risk factors
(e.g. blood pressure, blood lipid profile, BMI and waist-to-hip circumference)
to explore whether the changes in physical activity patterns relate to changes
in cardiovascular risk. Taken together, the nature and extent of burden and
risks associated with the intervention and measurements are negligible, whilst
the study potentially leads to significant health benefits.