According to new research from the University of Eastern Finland, obstructive sleep apnea (OBA) may have a more significant impact on the heart than previously noted. Patients with OBA have been found to show a higher immediate heart rate variability and greater changes in beat-to-beat intervals.
These new findings come from two recent studies that explored the immediate effect of respiratory events on heart rate variability and the association of OSA patients’ heart rate changes throughout the night with their alertness. The first study’s conclusion showed that a longer duration of respiratory events caused a more significant heart rate change and higher ultra-short-term heart rate variability. Both of these changes were greater during complete obstruction of the airway.
“The study sheds important new light on the cardiovascular load nocturnal respiratory events cause in patients with OSA,” the study’s lead author Early-Stage Researcher Salla Hietakoste says.
The second study found that pulse rate changes measured via finger photoplethysmogram were associated with performance in the psychomotor vigilance task (PVT) in patients with OSA. Those who performed poorly in the PVT showed a significantly higher nocturnal heart rate.
Researcher Samu Kainulainen concluded, “By taking a better look at polysomnography data for respiratory events and heart function, we might be able to identify patients who have a higher risk for reduced vigilance and alertness.”
Both studies found that outcomes were more pronounced in men compared to women. Researchers believe that more relationships between OSA and heart health could become available by using more of the data available from current clinical sleep studies. The data relating to heart rate variability could be used alongside the current diagnostic parameters for OSA to get a better understanding of the clinical picture and to identify high-risk patients better.
The Most Prevalent Sleeping Disorder
Obstructive sleep apnea affects approximately 1 billion people worldwide and is one of the most prevalent sleeping disorders that has significantly strained public health services.
Nocturnal respiratory events can involve complete or partial blocking of the airways, which can result in repeated oxygen desaturations and interrupted sleep. This can lead to abnormal nervous system function. The sympathetic nervous system’s abnormal hyperactivation affects heart function and cardiovascular regulation by increasing OSA patients’ nocturnal heart rate and reducing their long-term heart rate variability. It is changes such as these that have been shown to increase the risk of cardiovascular disease significantly.
Obstructive sleep apnea can also prevent patients from getting deep enough sleep, which is why they can often feel tired and less alert during the day.
Hyperactivation of the sympathetic nervous system can keep the body in a state of alertness over the long term despite sufficient deep sleep. This is often the case found in OSA patients with an elevated daytime heart rate.
With the number of cases of OBA on the rise, studies such as these are needed to identify patients who may be at higher risk than others for related illness and disease. They may also provide a better understanding of the condition itself and offer new preventative and treatment options.