Acute Effects of Sitting and Physical Activity on Cerebrovascular Circulation Among Adults

The study will be a controlled crossover experimental trial with three conditions involving 13 adult participants aged between 40 and 60 years. Each participant will complete each of the three experimental conditions, separated by a washout period of minimum four days. As well, physical activity behaviours and sleep the day/night before the test day will be measured. The first visit will be a familiarization session. On the second, third, and fourth visits, participants will undergo three different standardized 3-hour interventions in a randomized order. Before and immediately after the three-hour interventions, blood pressure, augmentation index, and cerebral hemodynamic response of the prefrontal cortex during standardized cognitive tasks (1,2, and 3-back tests) will be measured. Additionally, saliva samples will be collected the morning of the test day and before and after the interventions, blood glucose will be assessed continuously during the trial, and fitness will be measured at the familiarization visit.