Physiological Responses to Intermittent Hypoxic Training and Its Effect on Red Blood Cell Mass in Competitive Cyclists in Ogun State

Intermittent hypoxic training is an increasingly adopted strategy among elite athletes to stimulate erythropoietic adaptation, but evidence from African cycling populations remains absent in the scientific literature. This study examined the physiological responses to intermittent hypoxic training and its effect on red blood cell mass and haematological indices in competitive cyclists in Ogun State, South West Nigeria. A prospective experimental design enrolled 30 competitive male cyclists who underwent a six-week intermittent hypoxic training protocol using normobaric hypoxia chambers at simulated altitudes of 2500 to 3000 metres for ninety-minute sessions three times weekly. Full blood count including haemoglobin, red blood cell count, and reticulocyte percentage were measured at baseline, week three, and week six. Erythropoietin levels were assayed at each time point. Repeated-measures ANOVA and post-hoc tests were applied. Results showed progressive increases in erythropoietin from baseline to week three, followed by significant increases in red blood cell count and haemoglobin at week six. Reticulocyte percentage peaked at week three, confirming accelerated erythropoiesis. Performance indices measured by time-to-exhaustion on a cycle ergometer improved significantly. This study provides original physiological evidence for intermittent hypoxic training efficacy in Nigerian cyclists. Structured hypoxic training protocols are recommended for national cycling sports development programmes. Keywords: intermittent hypoxic training, erythropoiesis, haemoglobin, cyclists, competitive sport.