• Effects of interrupting prolonged sitting with high-intensity physical activity on postprandial metabolism

      Orton, Charlie J. (University of Bedfordshire, 2017-01)
      Aims The aim of this thesis was to explore the effects of interrupting prolonged sitting with high-intensity activity on cardiometabolic risk markers. Methods In study 1, participants completed 3, 8 hour trials: 1) uninterrupted sitting (SIT) 2) continuous moderate-intensity activity followed by sitting, and 3) sitting interrupted with hourly high-intensity activity (SIT-ACT). In study 2, participants completed 3, 6.5 hour trials: 1) SIT, 2) a continuous high-intensity interval exercise session followed by sitting (CON-HIE), and 3) sitting interrupted with high-intensity activity bouts (SIT-HIE). Postprandial incremental area under the curve (iAUC) was calculated for cardiometabolic risk markers and compared between conditions. Data are mean (95% confidence intervals). Results In study 1, glucose iAUC was not different between conditions (p= 0.606). Triglyceride (TG) iAUC was lower and high-density lipoprotein was higher in SIT-ACT than SIT (p=<0.05). In study 2, glucose iAUC was significantly lower in SIT-HIE than SIT (p=0.026), while TG iAUC was significantly lower in CON-HIE than SIT (p=0.014). Conclusion Study 1 observed beneficial TG and HDL responses to interrupting sitting with high-intensity activity. Study 2 observed suppressed glucose in response to interrupting sitting with high-intensity activity, but postprandial TG was reduced only in response to a high-intensity interval exercise session.