Obstructive sleep apnea (OSA) is a sleep disorder that can lead to heart disease, stroke and other health issues, such as insomnia. Although insomnia is relatively common among those with OSA, there has been little scientific consensus when it comes to determining why such a link exists.
A 2017 study published in Biomedical Research set out to investigate the incidence of insomnia in individuals with OSA. Researchers collected data from 123 people with OSA and 52 without the condition (the control group). Researchers measured insomnia and sleep quality using polysomnography (a type of sleep study) in addition to Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index questionnaires.
Researchers collected additional health data using the Depression Anxiety Stress Scales, the 12-Item Short Form Health Survey, and the National Institutes of Health Stroke Scale. They also recorded the health history of each participant.
The prevalence of insomnia and OSA
The study found that 57 percent of those with sleep apnea had insomnia, compared to 31 percent in the control group.
After splitting those with insomnia into two groups based on whether they had difficulty falling asleep or difficulty staying asleep, researchers found that those with sleep apnea were more likely to have difficulty staying asleep.
Risk factors for insomnia in those with sleep apnea
Researchers identified the following risk factors for insomnia among those with OSA:
- Age (older individuals were more likely to have insomnia)
- Gender (women were more likely than men to have insomnia)
- Previous stroke
- High blood pressure
After additional analysis, researchers found that gender and stroke history had the biggest association with insomnia.
Why does stroke appear to increase insomnia risk?
This study was the first to identify stroke as a risk factor for insomnia in individuals with OSA. Although the study did not examine why, researchers suggested that stroke may affect sites in the brain that are involved in regulating the sleep-wake cycle and releasing neurotransmitters associated with sleep.
Previous studies have found that depression rates increase after a stroke — and since depression is linked to insomnia, this may further explain the association.
Why is there a link between OSA and insomnia?
The authors pointed to previous studies that suggested many symptoms of OSA can cause insomnia. Such symptoms include:
- Breathing interruptions
- Slow or shallow breathing
- Involuntary movements during sleep
- Stimulation of the HPA axis (the body’s stress response system)
Are you living with more than one sleep disorder?
The study found that people with both OSA and insomnia exhibited more symptoms of depression, anxiety, and stress (as measured by the Depression Anxiety Stress Scales) and had a poorer quality of life (as measured by the Short Form Health Survey) compared to those with OSA alone.
If you are experiencing difficulty falling asleep and/or difficulty staying asleep, don’t assume it’s simply part of your sleep apnea. It’s entirely possible that you could be living with more than one sleep disorder.
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Martin is the creator of Insomnia Land’s free insomnia sleep training. His online course uses CBT techniques to teach participants how to sleep better without relying on sleeping pills. More than 5,000 insomniacs have completed his course and 97 percent of graduates say they would recommend it to a friend.