Elevated myocardial oxygen consumption during cutaneous cold stress in young adult overweight and obese Africans

37th Congress of IUPS (Birmingham, UK) (2013) Proc 37th IUPS, PCB013

Poster Communications: Elevated myocardial oxygen consumption during cutaneous cold stress in young adult overweight and obese Africans

T. A. Olaniyan1,2, L. A. Olatunji1

1. Physiology, University of Ilorin, Ilorin, Nigeria. 2. Public Health, The University of Northampton, Northampton, United Kingdom.

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Increased adiposity has been associated with high risk of developing hypertension and cardiovascular disease (1,2). Exaggerated sympathetic-mediated cardiovascular responses to stressful stimuli (such as exposure to cold) has been linked to the development of hypertension and cardiovascular disease (3,4), which in turn has been demonstrated to predict the development of future hypertension (5). The rate-pressure product (RPP) is considered as the best indirect method to evaluate myocardial oxygen consumption (MVO2) as well as an indicator of myocardial stress. The aim of the present study was to test the hypothesis that enhanced change in RPP to cutaneous cold stress may be one potential mechanism that predisposes overweight/obese individuals to developing hypertension. We determined heart rate (HR), blood pressure (BP), and RPP in 40 normotensive young individuals aged between 18 – 25 years at baseline and during sympathetic activation elicited by cutaneous cold stimulation (CCS). Following CCS, a change in RPP was also estimated. The median body weight of 59.50kg of the study population was used for classification. This was further standardized by also classifying the participants based on their body mass indices (BMI). There was no significant differences in the baseline RPP between the groups classified by body weight (P=0.629) or among the groups classified by BMI (P=0.415). However, following CCS, there was a significant enhanced RPP change in overweight individuals (P=0.019). Furthermore, multivariate regression analysis showed that BMI, but not body weight had a significant influence on RPP variation following CCS. Thus, it can be concluded that normotensive overweight or obese individuals have an exaggerated RPP response to the CCS. However, exposure to cold may augment sympathetic reactivity in overweight/obese individuals, which may contribute to increased risk of developing myocardial dysfunction, even in young normotensive individuals. Furthermore, RPP changes to CCS could be a useful simple measure for early detection of cardiac complications, particularly in low/middle income countries.



Where applicable, experiments conform with Society ethical requirements.

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