The importance of physical exercise tends to be neglected in today’s modern lifestyle. This increased passive way of life conveys a notable increase in the prevalence of lifestyle disorders such as hypertension and vascular pathology which lead to cardiovascular strain. Taking this into account, the aim of this investigation was to explore the empirical association between the heart health status of an active and sedentary South African lifestyle, thus intending to provide insight into impact of the significant changes that are associated with the modernised society. With the aforementioned objective in mind, four separate studies were completed: Study 1 sought to investigate the cardiovascular status of 162 undergraduate university students in order to determine whether, despite their youth, students remained at risk of cardiovascular complications. Astonishingly, results indicate that a number of students between the ages of 18 and 25 in a university setting present with preeminent cardiovascular risk. This data highlights some serious concerns regarding the cardiovascular health among the youth. In sequel to study 1, study 2 permitted the comparison of a sedentary and active South African population, however some discrepancies originated due to the notable age difference between the groups. Nevertheless, results gained from this crosssectional comparison between the populations indicate significantly higher cardiac risk amongst the sedentary population. Study 3 was conducted on 202 infantry service recruits between the ages of 18 and 24 years. A pre- post intervention study design was incorporated in pursuit of determining the influence of an intense training programme on cardiovascular variables of a population over a 20 week time-frame. Results yielded from this study indicate a significant decrease in overall cardiovascular risk, as tested over three intervals (week 1, week 12, and week 20) during the 20 week training period. Study 4 was designed as a longitudinal study with self-controls for within group comparisons, as well as a comparative study between the two contrasting populations. Thus, affording the opportunity to determine the impact of physical activity on cardiovascular risk by comparing two divergent South African lifestyles over a 20-week time frame. The 202 infantry service recruits of study 3 served as the intervention group, while the control group comprised of 126 sedentary university students. Findings from this study conveyed strong association between the active population and decreased cardio-stress index and related heart health measurements in comparison to results of the sedentary population. This research validates the positive correlation between a physically active lifestyle and improved heart health, thereby implying reduced cardiovascular risk. In the combat against cardiovascular disease it is clear that focus should be shifted from pharmacological treatment to behavioural prevention. As a principle component of this preventative approach it is vital that individuals are equipped with screening technology that enables early detection and monitoring of probable cardiovascular complications. Several novel ideas were introduced in this research, including the endorsement of the cardio-stress index method as an efficient non-invasive technique to directly observe cardiovascular stress. / Dissertation (MSc)--University of Pretoria, 2014. / lk2014 / Physiology / MSc / Unrestricted