Building Bridges between Physical Activity and Diet to improve (cognitive) health after a meal

Rationale: Sedentary behaviour is an independent risk factor for cardiovascular disease, type II diabetes and all-cause mortality and might also be related to impaired cognitive function. In society today, often unhealthy meals are consumed (e.g. high fat/high calorie) followed by prolonged periods of sitting. Resultantly, people are exposed to the negative effects of sitting and of the meal. Much research has been done to determine if reducing sitting can improve metabolic health and results suggest that breaking up sitting with low-intensity or moderate physical activity can modulate cardiovascular risk factors. However, less is known about how a meal could interfere with the acute effects of sitting and/or breaking up sitting on cardiovascular and cognitive health.

Objective: The primary objective of this study is to determine whether the content of a meal alters the impact of prolonged, uninterrupted sitting and breaking up prolonged sitting on cognitive function. The secondary objective is to determine these impacts on cerebrovascular health, metabolic health and perceivable benefits to better understand possible underlying mechanisms. The tertiary objective is to explore the role of inflammation and oxidative stress in mediating the impact.

Study design: Cross-over design.

Study population: 24 overweight or obese (age >= 45 years, BMI 25 kg/m2 - 35 kg/m2), sedentary (sitting more than 40 hours a week) men and women.

Intervention (if applicable): Participants report 4 times to our laboratory and will receive either a western type breakfast or a 'healthy' breakfast. After the meal, they will be exposed to four hours of continuous sitting or sitting interrupted with 5 minute bouts of moderate intensity physical activity every 30 minutes. In total, participants will be exposed to four different combinations (in a randomized order on different days) of a breakfast and sitting/physical activity, with a wash-out period of one week in between conditions.

Main study parameters/endpoints: The main study parameter is cognitive function, assessed as flexibility, alertness and working memory with the computerized Test of Attentional Performance (TAP). Secondary parameters are cerebrovascular health (i.e. coronary artery reactivity, brain-derived neurotrophic factor levels), metabolic health (i.e. glucose, insulin, cholesterol, triglyceride levels) and perceivable benefits (i.e. mood, satiety/hunger and sleepiness, measured with specific questionnaires). Tertiary parameters are markers for inflammation and oxidative stress.

The composition of a meal might influence the effect of breaking up prolonged sitting on cognition

One screenings visit.

After enrollment, four visits with a one week period in between.

Participants report 4 times to our laboratory and will receive either a western type breakfast or a 'healthy' breakfast. After the meal, they will be exposed to four hours of continuous sitting or sitting interrupted with 5 minute bouts of moderate intensity physical activity every 30 minutes. In total, participants will be exposed to four different combinations (in a randomized order on different days) of a breakfast and sitting/physical activity, with a wash-out period of one week in between conditions.