What Is an AHI (Apnea-Hypopnea Index)?

The apnea-hypopnea index measures the average number of apnea-hypopnea events per hour of sleep. In other words, this is the measure of how many times your breathing pauses per hour. We measure the severity of sleep apnea on the following scale.

What Is Sleep Apnea?

When your airway collapses during sleep, air cannot get to the lungs. This leads to a brief arousal from sleep that causes fragmentation and poor sleep quality. This cycle can repeat hundreds of times in one night, but typically these events are not remembered in the morning.

Your bed partner may notice that you snore loudly or repeatedly stop breathing. Untreated Obstructive Sleep Apnea can cause daytime sleepiness and can even affect your mood. It also increases the risk of obesity, high blood pressure, heart disease, stroke, Type 2 diabetes, dysfunction, and depression.

Patients with untreated obstructive sleep apnea (OSA) are at a higher risk for many health complications, including but not limited to:

  • Increased risk of stroke
  • Coronary Artery Disease
  • Atrial Fibrillation
  • Congestive Heart Failure
  • Daytime fatigue
  • Hypertension / High Blood Pressure
  • Diabetes Type II
  • Heart Attack
  • Increased risk for automobile/work accidents
  • Morbid Obesity
  • Depression
  • Memory loss
  • Lack of concentration
  • Erectile Dysfunction

Associated Health Risks


Blood pressure

Improved blood pressure. Decreased risk for sudden cardiac death, hypertension, heart disease.


Decreased risk of stroke. Improved alertness, mental focus, memory and work performance.


Improved mood, reduced risk of depression, anxiety, and lower prevalence of suicide.


Improved insulin sensitivity, lower glucose levels, reduced risk of type II diabetes.


Improved lung function, reduced mortality rate in COPD cases and improved asthma.

Auto accidents

Reduced risk of automobile and workplace accidents.


Improved libido, sexual function, and increased desire.


Lower annual medical expenses.

Brain Waves

What happens when I sleep?
Sleep Stage: Description:
Stage 1 (N1) NREM This is the transition stage between wakefulness and sleep. It is also called light sleep and dreamless sleep. You may wake up during this stage feeling like you did not sleep at all. People also can or may experience a hypnic jerk of falling asleep during this stage.
Stage 2 (N2) NREM During Stage 2, your heartrate slows and there is a decrease in body temperature. It is harder to wake someone up during this stage. Most of the night’s sleep is spent in Stage 2.
Stage 3 (N3) NREM Stage 3 typically starts 35-45 minutes after falling asleep. The brain waves slow down and become larger. Your muscles relax while the deepest sleep occurs. The body repairs and regrows tissues, builds bones and muscle, and strengthens the immune system. The Growth Hormone is released during Stage 3 which is also called delta sleep and slow wave sleep.
REM Sleep REM occurs after 90 minutes of sleep. Powerful dreams and rapid eye movement happen since the brain is more active during this stage. The heart and respiration rates increase. This stage is known as paradoxical sleep since the brain waves look like you are awake. Even with heightened brain activity the muscles are paralyzed so a person cannot act out their dream. This stage consist of 25% of each night’s sleep.

Normal Sleep Architecture

This Sleep architecture shows a person who has Obstructive Sleep Apnea. They are waking up multiple times during each sleep cycle. We can see that they are only able to complete two sleep cycles a night, while a healthy person who has normal sleep architecture completes anywhere between six to eight sleep cycles. Abnormal sleep usually does not reach REM multiple times a night which is the most restorative of each sleep stage.