Obstructive sleep apnea is classified by severity: Severe obstructive sleep apnea means that your AHI is greater than 30 (more than 30 episodes per hour) Moderate obstructive sleep apnea means that your AHI is between 15 and 30.
An ideal AHI is fewer than five events per hour. That rate is within the normal range. Some sleep specialists aim for one or two events per hour so you're getting better sleep.
AHI or REI <5/hour = normal (for adults); 5–14.9/hour = mild OSA; 15–29.9/hour = moderate OSA; and ≥30/hour = severe OSA.
All patients with an apnea-hypopnea index (AHI) greater than 15 are considered eligible for CPAP, regardless of symptomatology.
Studies show that patients who develop sleep apnea before the age of fifty have a life expectancy between 8 and 18 years. Fortunately lifestyle changes, treatment, and other interventions can improve the life expectancy of someone with sleep apnea.
Weight loss of just 10-15% can reduce the severity of OSA by 50% in moderately obese patients. Unfortunately, while weight loss can provide meaningful improvements in OSA, it usually does not lead to a complete cure, and many sleep apnea patients need additional therapies.
AHI of 30 or Higher: This is considered severe sleep apnea. If you're active with your CPAP therapy and you get a score this high, it's a sign that your therapy isn't working. You'll need to see your doctor as soon as possible to figure out what the next steps are.
"If you're born with a high IQ say 180 and you lose 8 to 10 points, which is about the extent of IQ loss that sleep apnea will induce on average, that may never become apparent.
Mild sleep apnea – You stop breathing 5-14 times per hour. Moderate sleep apnea – You stop breathing 15-29 times per hour. Severe sleep apnea – You stop breathing 30+ times per hour.
More than usual daytime sleepiness. Waking up with a dry throat or headache. Waking up often during the night. Difficulty concentrating or mood changes during the day.
This happens either because of blockage of your airway (obstructive sleep apnea) or because your brain doesn't correctly control your breathing (central apnea). The resulting lack of oxygen activates a survival reflex that wakes you up just enough to resume breathing.
Alcohol, medicine and other drugs: The periodic use of certain medication, alcohol or narcotics may cause your AHI to go up. Ask your doctor if anything you're taking could be causing your fluctuation, and how you can compensate for it.
If your symptoms haven't gotten better with a CPAP or BiPAP machine, it could be because: You're wearing the wrong size or style mask. A mask that leaks can irritate your skin and make your eyes, nose, and mouth dry out. You haven't given it enough time.
Sleep Apnea and Brain Tissue Damage
Beyond memory problems, sleep apnea can also cause physical, measurable brain damage by starving your brain of oxygen. A recent study published in Sleep Journal found significant reductions in gray matter in certain areas of the brains of sleep apnea patients.
Many people with sleep apnea are undiagnosed
The National Sleep Foundation reported that sleep apnea likely affects as much as 20% of the population, and it's been found that around 85% of individuals with sleep apnea don't know they have it. Part of this may be because the symptoms of sleep apnea are somewhat general.
You can receive a rating of 0, 30, 50, or 100 percent for sleep apnea.
Determining Required CPAP Pressure
The maximum setting varies with the type of machine, but it could be as high as 25 or 30 CWP. The average setting often lies between these two extremes. Levels above 15-20 CWP may require a change to bilevel therapy, (BPAP).
The amount of time that a sleep apnea patient stops breathing can be from 10 seconds to two minutes or more. These breathing "stoppages" can happen a few times per hour or, in more severe cases, 60-100 times per hour or to the point where someone spends more time NOT breathing than they are breathing.
While there is no cure for sleep apnea, studies show that certain lifestyle factors can reverse or make your sleep apnea less intense. Other treatment or surgical options can also reverse the condition. Sleep apnea happens when your upper airway muscles relax while you sleep. This causes you to not get enough air.
It's not clear why CPAP therapy causes weight gain. It could be due to the treatment causing a decrease in leptin levels, but not a change in leptin resistance, leading to increased hunger. CPAP may also lead to reduced energy expenditure during sleep as breathing becomes easier.
Abdominal adipose tissue distribution and blood lipid levels
Sleep apnoea patients had significantly higher amounts of intra-abdominal visceral fat at all five levels (table 2). Also, total VAT area was significantly higher in OSA patients than controls.
Three months of CPAP therapy reduced the basal metabolic rate in the absence of changes in physical activity, thus favoring a positive energy balance in terms of energy expenditure.