What is Hypoxic Burden?

Hypoxic burden is a cumulative measure of the total physiological impact of oxygen desaturation events occurring during sleep. Rather than simply counting the number of apneas and hypopneas, hypoxic burden quantifies both the depth (severity) and duration of each oxygen desaturation. It is calculated as the area under the oxygen desaturation curve across the entire sleep period, integrating the magnitude of SpO₂ drops with the time spent below baseline.

By capturing the overall “dose” of hypoxemia rather than isolated events, hypoxic burden offers a more comprehensive assessment of the strain placed on the cardiovascular and metabolic systems. This metric has been shown in research to correlate strongly with cardiovascular morbidity, all-cause mortality, and other long-term health outcomes—making it an increasingly important parameter in the evaluation and management of sleep-disordered breathing.