AHI: Understanding the Apnea Hypopnea Index

If you’re suffering from sleep apnea, you may wonder how the condition can be measured or quantified. As it happens, there’s a generally accepted metric for calculating your severity level of obstructive sleep apnea.

The AHI, or Apnea Hypopnea Index, was devised to measure the extent to which an individual is suffering from sleep apnea. Specifically, it looks at the number of times an individual experiences sleep apnea (complete stoppage of breathing) and hypopnea (partial loss of breath) while sleeping. To qualify for inclusion in an AHI calculation, any episodes of sleep apnea or hypopnea must last a minimum of ten seconds.

To calculate your AHI, take the number of times you experience apnea or hypopnea during the night, and divide it by the number of hours you were asleep. What do your AHI numbers mean?

  • AHI score of less than five qualifies as normal sleep.
  • AHI of 5-14 events per hour: mild sleep apnea.
  • AHI of 15-29 events per hour: moderate sleep apnea.
  • AHI of 30+ events per hour: severe sleep apnea.

As a side note, this is the scale used for adults. Because children are generally at much lower risk for sleep apnea, an AHI above one is considered unusual, and if a child’s AHI is more than five, they’re generally considered in need of treatment for pediatric sleep apnea.

If you suspect you’re suffering from sleep apnea, you might consider starting with our online quiz to understand some of the classic symptoms. (If you’re concerned about your son or daughter, look at our online quiz for pediatric sleep apnea.)

To get an AHI calculation, you’ll need to undergo a sleep study. While an in-lab or in-office overnight sleep study is inconvenient and expensive for a lot of people, Dr. Krish offers an at-home sleep study that is easy and affordable, and produces a range of data alongside your AHI calculation.

Source: Apnea Hypopnea Index (AHI) (WebMD)