20 minutes of moderate to vigorous exercise at 50-80% maximum heart rate to be performed on a cycle ergometer 40 minutes from the start of the testing session following consumption of a glucose solution at 0 mins. Glucose readings from the FreeStyle Libre to be taken at 0 mins, 30 mins, 60 mins, 90 mins and 120 mins. Cognitive tests to be carried out before the glucose solution is administered at 0 mins and at the 120 min point.

4 bouts of 5 minutes of moderate to vigorous exercise at 50-80% maximum heart rate to be performed on a cycle ergometer 30 minutes from the start of the testing session and repeated at 60 mins, 90 mins and 120 mins following consumption of a glucose solution at 0 mins. Glucose readings from the FreeStyle Libre to be taken at 0 mins, 30 mins, 60 mins, 90 mins and 120 mins. Cognitive tests to be carried out before the glucose solution is administered at 0 mins and at the 120 min point.

A sitting only exposure, glucose solution to be consumed at 0 mins.Glucose readings from the FreeStyle Libre to be taken at 0 mins, 30 mins, 60 mins, 90 mins and 120 mins. Cognitive tests to be carried out before the glucose solution is administered at 0 mins and at the 120 min point

Participants randomised to one of the three exposures

The main outcome will be change in executive functioning from the start to the end of the session using the Eriksen Flanker Task. The test measures selective attention and executive control and measures speed (milliseconds) and accuracy (number of responses correct). This will be performed before the oral glucose tolerance test and again at the end of each session.

Wechsler Intelligence Scale for Children (WISC) Digit Span will test attention and working memory. The total score is calculated by the number of correct responses. This will be performed before the oral glucose tolerance test and again at the end of each session.

On arrival an OGTT, simulating insulin and glucose response comparable to that following a meal will be given. Children will follow an identical protocol for OGTT during all conditions. Children will be asked to fast the night before, for 10 hours prior to the test. They will arrive fasted, have a baseline glucose reading taken and will be given the OGTT, followed by sit only or sit in addition to physical activity breaks regimens. For the OGTT the stimulus is 1.75g/kg body weight of glucose solution. A Freestyle Libre glucose monitoring system will be placed on the participants' arm and glucose readings will be monitored at timed intervals.