Heterogeneous responses of personalised high intensity interval training on type 2 diabetes mellitus and cardiovascular disease risk in young healthy adults

Hypertension, decreased glucose tolerance, adverse lipid profiles and low physical activity levels are associated with increased type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) risk. High intensity interval training (HIIT), a low volume, reduced time, high intensity programme, may be a useful alternative to current government guidelines which specify a minimum of 150 minutes of physical activity per week. We describe a personalised programme of high intensity exercise which provides significant improvements in CVD risk markers. Healthy volunteers undertook 6 weeks of HIIT. T2DM and CVD risk predictors including glucose tolerance, VO_2max, blood pressure (BP), and lipids were measured before and after HIIT. HIIT training was associated with beneficial changes in a range of predictors of blood flow and cardiovascular risk. There was a heterogeneous response to HIIT, with some subjects responding with favourable changes and others being non-responders to HIIT. In responders, HIIT was associated with a statistically significant (p = 0.023) increase in VO_2max, from 45.4 (38.4,52.5) to 56.9 (51.2,65.7) (median (interquartile range)(ml/min/kg)). In responders HIIT resulted in a decrease in systolic BP from 127 (126,129) to 116 (106,122) (mmHg) with p = 0.026 and a decrease is diastolic blood pressure from 72 (69,74) to 57 (56,66) with p = 0.026. There was also some evidence of a beneficial change in blood lipid and glucose concentrations with HIIT. In conclusion, personalised HIIT has potential as an intervention to improve blood flow and cardiovascular health.