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According to the national survey of genetic blood disorders, the prevalence of haemoglobinopathies in Oman is 9.5% with Sickle Cell Disease (SCD) and Sickle Cell Trait (SCT) representing two major public health concerns and having great impact on individuals’ lives as well as on society (Al-Riyami et al., 2001). Complications related to SCD arise owing to ischemic tissue injury and may result in organ dysfunction and premature death. Patients with SCD often experience painful crises (vaso-occlusion), renal disease, acute chest syndrome (ACS) and other lifethreatening conditions. Physical education teachers tend to exclude children with SCD from PE classes due to their health status. It is currently unknown whether exercise might have beneficial, adverse or no effect in children and adults with SCD. Consequently, the recommendation of exercise for children and adults with SCD is rare. accordingly, there were three objectives to the work within this thesis: First, to investigate physical fitness markers in SCD and SCT and compare them to normal healthy children. With no reference data available, the aim of the first study was to provide a general idea of this population’s physical fitness parameters. The results suggest that children with SCT had similar anthropometric measurements, physical fitness and exercise responses to normal healthy children. In contrast, SCD children who were shorter and had lower body mass, higher fat mass and lower physical fitness than SCT and normal healthy children. In addition, children with SCD exhibited higher heart 3 rate and blood lactate responses in response to exercise than SCT children and normal healthy children. The second study was designed to determine cardiovascular responses to exercise in children with SCD and SCT and to compare them with those of normal healthy children from the same age ranges. Normal healthy children had a significantly higher estimated maximal oxygen uptake (VO2max) than SCT and SCD children (P < 0.05), with SCD children achieving the lowest VO2max. The mean heart rate in SCD and SCT was significantly higher during sub-maximal exercise than in normal healthy children (P < 0.05). White blood cell (WBC) count was also higher (P < 0.05) in the SCD group than in the other two groups, which is suggestive of a chronic inflammatory state. The third study aimed to determine whether a single bout of exercise elicits changes in interleukin- 6 (IL-6) concentrations in children with SCD. Children with SCD exhibited higher baseline IL-6 concentrations than the normal healthy children (P < 0.05), suggesting a persistent inflammatory state. However, the exercise bout did not elicit a significant change in IL-6 concentrations in either normal healthy or SCD children. The final study investigated the effect of an acute bout of exercise on postprandial changes in triacylglycerides (TAG), glucose, insulin and total cholesterol. Postprandial TAG concentrations were reduced in the exercise trial (P < 0.05). The postprandial glucose and insulin responses were also reduced in the exercise trial (P < 0.05). In conclusion, the work in this thesis suggests that Omani children with SCD have lower physical fitness than normal healthy children, and that exercise might have beneficial effects on this population. The lower physical fitness of SCD children is associated with altered body composition and lower oxygen-carrying capacity of the blood, as these children had shorter stature, lower body mass, higher fat mass and exhibited lower VO2max. The potential benefit of exercise for this population is demonstrated by the alterations of postprandial lipaemia after an acute bout of exercise. Higher TAG has been associated with increased incidence of vaso-occlusive events in subjects with SCD, and exercise lowered postprandial TAG concentrations in children with SCD. |
