Noncommunicable diseases (NCDs) are now the leading cause of death and disability worldwide, with cardiovascular diseases being the number one cause. Because of the recent changes in world demographics with an increasing number of elderly and obese, NCDs are expected to increase in the years to come. Physical inactivity is one of the most important risk factors for cardiovascular disease, and aerobic exercise training is shown to improve both aerobic capacity and endothelial function, two important and strong prognostic factors for cardiovascular mortality. However, little is known about the effects of high intensity exercise on cardiovascular risk factors in elderly and obese subjects.
October 8th, Gertrud Aunet Tyldum defended her Ph.D. ” Effects of different exercise modalities on maximal oxygen uptake and endothelial function in subjects at risk of cardiovascular disease “. Ulrik Wisløff and Øivind Rognmo has been her supervisors. This is a summary of her doctoral dissertation.
The main purpose of this thesis was to investigate the effects of high intensity interval training (HIIT) on aerobic capacity and endothelial function in subjects at risk for cardiovascular disease e.g. obese and elderly subjects. HIIT was compared to moderate intensity continuous training (MICT) as well as strength training (ST) in the obese subjects. Also we searched to find how different exercise-intensities would affect the postprandial vascular function in overweight subjects.
The results in this thesis demonstrates that HIIT was superior to MICT and ST in improving aerobic capacity and endothelial function in obese adults. Furthermore, we demonstrate that HIIT afforded better protection than MICT upon the vasculature after a high fat meal, an effect that appears to be related to the exercise-induced antioxidant level in plasma. Among the elderly subjects there was a distinct improvement of both aerobic capacity and vascular function after eight weeks of HIIT, and there was a significant relationship between the antioxidant status in plasma and training-induced improvement in vascular function. Furthermore, we found that the vascular function of well-trained elderly was comparable to that of young athletes.
Together, the studies of this thesis demonstrate that HIIT is superior to MICT and ST in improving important risk factors for cardiovascular diseases in elderly and obese, and thus highlights the importance of high intensity exercise for the prevention of caused by an unhealthy lifestyle.
Gjertrud Aune Tyldum, Ph.D student at CERG