AHI Calculator | Apnea-Hypopnea Index

The calculation divides the total count of breathing interruptions by your total minutes of sleep, then scales the result to an hourly rate. The formula is expressed as: AHI = ((Apneas + Hypopneas) / Sleep Time in Minutes) * 60. An apnea represents a complete cessation of airflow for at least 10 seconds, while a hypopnea denotes a partial reduction in airflow accompanied by a drop in blood oxygen saturation or arousal.

Imagine a patient undergoes an overnight sleep study. During a total recorded sleep time of 420 minutes (7 hours), the monitoring equipment detects 70 apneas and 35 hypopneas. First, we sum the respiratory events: 70 + 35 = 105 total events. Next, we divide this sum by the total sleep time: 105 / 420 = 0.25 events per minute. Finally, multiplying by 60 gives the hourly AHI score: 0.25 * 60 = 15 events per hour. This indicates moderate obstructive sleep apnea.

Always ensure your sleep study duration reflects actual asleep time rather than total time spent in bed to maintain calculation accuracy. Remember that AHI scores can vary significantly depending on sleeping positions, such as sleeping on your back versus your side. Consult a qualified sleep physician to interpret your raw data comprehensively alongside your clinical symptoms and overall cardiovascular health.