Sickle Cell Trait and Physical Exercise Tolerance Among Secondary School Students in Owerri, Imo State, South East Nigeria

Background: Sickle cell trait, the heterozygous carriage of one haemoglobin S allele, has been associated with exercise-induced complications including exertional rhabdomyolysis and, rarely, sudden cardiac death under conditions of extreme physical exertion. Whether sickle cell trait meaningfully limits exercise tolerance under normal physical education conditions in Nigerian secondary schools is debated. Objectives: This study seeks to compare aerobic exercise tolerance, recovery heart rate, and subjective exertion ratings between secondary school students with sickle cell trait and those with normal haemoglobin AA genotype during a standardised step test in Owerri, Imo State. Methods: Forty confirmed sickle cell trait students and eighty haemoglobin AA controls, genotyped by haemoglobin electrophoresis, will perform a standardised three-minute step test. Heart rate will be measured at rest, immediately post-test, and at one and three minutes recovery. Oxygen saturation will be monitored by pulse oximetry. Borg perceived exertion will be recorded post-test. Independent t-tests will compare cardiovascular responses. Expected Outcomes: Sickle cell trait students are expected to demonstrate slightly higher post-exercise heart rates and marginally lower oxygen saturations compared to haemoglobin AA peers, though within clinically acceptable ranges under the standardised test conditions. Conclusion: Findings will clarify safe physical activity boundaries for sickle cell trait students in Nigerian secondary schools. Keywords: sickle cell trait, exercise tolerance, aerobic capacity, recovery heart rate, Imo State.