Exercise Effects on Appetite-regulating Hormones and Cardiovascular Risk Factors

Cardiovascular diseases are recognised as the number one cause of death globally. Furthermore, diabetes is a major risk factor for cardiovascular disorders with abundant evidence showing that patients with type 2 diabetes (T2D) are at higher risk of cardiovascular disease (CVD) than those with a normal glycaemia.

In contrast to the declining numbers in the Western world, the prevalence of CVD and T2D is growing in low - and middle - income countries accompanied by a rapid increase of mortality and morbidity. Of interest, a rise in CVD prevalence has been particularly observed in people of South Asian origin including India, Bangladesh, Pakistan, Sri Lanka or Nepal with a projection showing that in this population deaths attributed to CVD will rise globally to nearly 36 % in 2030 compared to 29 % in 2005. South Asians collectively form 20% of the global population while in the UK they are the largest ethnic minority group representing over 5% of the total UK population .

Although the majority of research has been conducted mainly on White individuals, recent studies have revealed that traditional CVD risk factors such as hypertension, dyslipidaemia, insulin resistance and diabetes are higher in South Asians than other ethnicities. The factors underlying the high CVD risk in this population remain largely unexplained even though genetic predisposition and physical inactivity could play a key role. In contrast to European counterparts, sedentary lifestyles or physical inactivity have been identified as an important coronary heart disease (CHD) risk factor in South Asians. A systematic review from the United Kingdom (U.K.) showed that South Asians are participating in up to 50-75% less physical activity compared to their European counterparts.

In addition to the traditional risk factors there are emerging biomarkers which could represent meaningful predictors of metabolic disorders and related complications. Specifically, appetite hormones secreted mainly by the gastrointestinal tract, such as Acylated Ghrelin or Peptide YY (PYY) have shown potential effects on glucose homeostasis and cardiovascular system. Current experimental studies suggest beneficial cardiovascular, anti-inflammatory and anti-apoptotic effects of ghrelin in the cardiovascular system.

Although evidence suggests that ghrelin may be a potential metabolic risk factor and is important in appetite regulation, no studies to the researcher's knowledge have examined changes of this peptide in South Asians despite the fact that CVD and T2D burden in the South Asian population is growing. Likewise, although studies have investigated the effects of exercise on ghrelin and other appetite hormones, no study has taken in consideration the effects of exercise on appetite gut hormones in South Asian populations.

Therefore, this research project aims to examine specific appetite hormones in response to a single bout of exercise, standardised meal and ad libitum buffet meal, with a comparison between South Asians and White Europeans identifying potential relationships with genetic and other metabolic risk factors.