Activity during television advertisement breaks to offset the adverse effects of prolonged sitting: The ‘Active Ads’ study

The study will be a randomised crossover trial involving sedentary individuals or couples. The study will involve, one familiarisation session and two acute experimental conditions (each of approx. 4 hours duration) at the Physical Activity Laboratory. Both conditions will occur in the evening (between 6 and 10pm) as this is the time period of peak TV viewing time in most adults and coincides with the post-evening meal period. Following successful completion of the phone screening, the study coordinator will explain the project in lay terms, initially over the telephone. Inclusion/exclusion criteria will be discussed and, provided the participant is suitable and willing to take part, they will be sent (either by mail or email) a copy of the patient information and consent form (PICF), to get informed consent for wearing two objective activity monitors in the week prior to the trial (for a 10 day period) and to record their diet (for a 5 day period) during the trial week. They will be called back in the following days to discuss any concerns, before being asked to send back the signed PICF. Once the Baker IDI study coordinator receives the PICF, they will send the activity monitors and diaries (with instructions) via mail to each potential participant which they will wear for a 10 day period, starting Thursday (in the week prior to the trial) until Sunday (in the week of trial). In order to allow orientation with the testing procedures and measurement devices, a baseline familiarisation session will take place at the Baker IDI Physical Activity Laboratory on the day preceding the first condition. During the familiarization visit (Monday) the study staff will fit participants with a continuous glucose monitor (CGM) which they will wear for a 5 day period during the trial week (Monday to Friday evening). The CGM will require the participants to take 3 blood samples (just before breakfast, lunch and dinner) with a finger prick blood taking device provided by the research staff. Study staff will also show them the 24 hour ambulatory blood pressure monitor (24 hour ABPM) which they will wear from Tuesday to Wednesday night and Thursday to Friday night. In addition anthropometric measurements and demonstration and practice of the simple resistance exercises will also be done. Activity monitors (which will have been posted the week prior) along with the activity diaries and food diaries will be checked as well. Participants will be instructed not to alter their habitual pattern of daily activities while involved in the trial. To assess compliance and habitual physical activity, participants will be instructed on how to fit two objective activity monitors in the week prior to the trial – an accelerometer (Actigraph model GT3X) worn on the hip, and an inclinometer (activPAL) worn on the thigh. The objective activity monitoring will be used in combination with an activity diary. The study will involve two acute (4 hour) experimental conditions, supervised by the study staff, in the evening after work (Tuesday and Thursday), and separated by a 1-day washout period. The research group consisting of the coordinator and research assistant will be responsible for monitoring adherence to the interventions; 1) Uninterrupted sitting: Participants will sit for the entire duration of a TV movie (roughly for 3 hours), after consumption of an evening meal, including during intermittent (every 20 minute) advertisement breaks (of 3 minutes). 2) Interrupted sitting: Identical procedure to Condition 1, except that participants will get up and perform simple resistance exercises during the advertisement breaks. The 3 minutes will be divided into a total of nine 20 second segments, alternating between body weight half-squats, calf raises and brief gluteal contractions in-between single leg knee raises (total exercise time equals to 27 minutes). This interchange between movements will provide rest for the corresponding muscle groups between each activity segment, allowing for continual muscle activation over the 3 minute period. To ensure appropriate movement standardisation, tempo, and correct ‘form’, participants will mimic a pre-prepared video recording which will be practiced prior to their first condition visit (see Familiarisation). Range of motion (knee/hip 45 to 90 degrees for half-squats/knee raises) will also be tailored to the individual ahead of time. Activity intensity will be monitored using heart rate and the Borg Scale of relative perceived exertion (RPE). Participants will be instructed to minimise excessive movement when sitting; only rising from the seated position to void. As boredom has been shown to influence food intake the movie will be self-selected by participants from a library of pre-determined series. On each testing day, participants will consume standardised dinner meal according to their body mass and height. To employ a pragmatic approach and assimilate a typical Western dietary composition, the ‘real world’ dinner meal will comprise of 45% of estimated daily energy requirements, with a macronutrient profile of 53-55% energy from carbohydrate, 12-15% energy from protein, and 30-33% energy from fat. After the completion of the trial, the participants will remove all the devices (CGM, 24 hour ABPM, and activity monitors), put in a pre-prepared envelope and mail it back to Baker IDI.