Obstructive sleep apnoea (OSA) is a common disorder characterized by repeated upper airway collapse during sleep, leading to oxygen desaturation and disrupted sleep. Symptoms include snoring, witnessed apnoea, and excessive daytime sleepiness. Risk factors include obesity, male sex, age, menopause, fluid retention, adenotonsillar hypertrophy, and smoking. OSA is linked to sleepiness, road traffic accidents, and systemic hypertension, as well as cardiovascular, metabolic, and neurocognitive effects. Continuous positive airway pressure (CPAP) is the primary treatment, with adherence rates of 60–70%. Alternative treatments include bi-level positive airway pressure, adaptive servo-ventilation, dental devices, surgery, and weight loss. OSA pathogenesis involves anatomical and neuromuscular factors, including small upper airway lumen, unstable respiratory control, low arousal threshold, and dysfunctional upper airway dilator muscles. The condition is influenced by factors such as lung volume, respiratory control stability, and upper airway anatomy. Men are more likely to develop OSA due to anatomical differences and central fat distribution, while age and obesity are also significant risk factors. Diagnosis involves polysomnography, with the apnoea-hypopnoea index (AHI) as the primary outcome measure. Home-based diagnosis and treatment are increasingly used, though not suitable for all patients. OSA has significant consequences, including systemic hypertension, cardiovascular events, and diabetes. While CPAP is effective, adherence can be challenging, and alternative treatments are being explored. Management includes CPAP, which is cost-effective and improves neurocognitive and cardiovascular outcomes. Other options include oral devices, upper airway surgery, positional therapy, and weight loss. Preventive strategies involve weight loss, avoiding alcohol and sedatives, and lifestyle modifications. Future research aims to develop targeted treatments based on individual pathophysiology, including drugs to block apnoea or its consequences. Despite advances, challenges remain in improving adherence and long-term outcomes for OSA patients.Obstructive sleep apnoea (OSA) is a common disorder characterized by repeated upper airway collapse during sleep, leading to oxygen desaturation and disrupted sleep. Symptoms include snoring, witnessed apnoea, and excessive daytime sleepiness. Risk factors include obesity, male sex, age, menopause, fluid retention, adenotonsillar hypertrophy, and smoking. OSA is linked to sleepiness, road traffic accidents, and systemic hypertension, as well as cardiovascular, metabolic, and neurocognitive effects. Continuous positive airway pressure (CPAP) is the primary treatment, with adherence rates of 60–70%. Alternative treatments include bi-level positive airway pressure, adaptive servo-ventilation, dental devices, surgery, and weight loss. OSA pathogenesis involves anatomical and neuromuscular factors, including small upper airway lumen, unstable respiratory control, low arousal threshold, and dysfunctional upper airway dilator muscles. The condition is influenced by factors such as lung volume, respiratory control stability, and upper airway anatomy. Men are more likely to develop OSA due to anatomical differences and central fat distribution, while age and obesity are also significant risk factors. Diagnosis involves polysomnography, with the apnoea-hypopnoea index (AHI) as the primary outcome measure. Home-based diagnosis and treatment are increasingly used, though not suitable for all patients. OSA has significant consequences, including systemic hypertension, cardiovascular events, and diabetes. While CPAP is effective, adherence can be challenging, and alternative treatments are being explored. Management includes CPAP, which is cost-effective and improves neurocognitive and cardiovascular outcomes. Other options include oral devices, upper airway surgery, positional therapy, and weight loss. Preventive strategies involve weight loss, avoiding alcohol and sedatives, and lifestyle modifications. Future research aims to develop targeted treatments based on individual pathophysiology, including drugs to block apnoea or its consequences. Despite advances, challenges remain in improving adherence and long-term outcomes for OSA patients.