Lack of sleep and an increase in strokes. According to new research,
the two conditions are very connected, even in otherwise healthy adults.
In early June, the University of Alabama at Birmingham released the results of a study that regularly sleeping less than six hours a night significantly increases the risk of stroke symptoms in middle-age to older adults who are of normal weight and at low risk for obstructive sleep apnea (OSA). That’s worth repeating: Less than six hours of sleep per night increases the risk of strokes in adults of normal weight and not at risk for OSA.
It seems that under six hours of sleep per night is the critical variable, but why? Let’s take a look at the study. The University of Alabama researchersfollowed 5,666 people for up to three years who had no history of strokes or stroke-like symptoms, transient ischemic attacks (when blood flow to the brain stops for a brief period causing stroke-like symptoms), or high risk for OSA at the start of the study.
For a period of three years, the researchers followed and studied the subjects’ first stroke symptoms, stroke risk factors, depression symptoms, demographic information and other various health behaviors. What they found was—after adjusting for body-mass index (BMI)—there was a strong association between daily sleep periods of less than six hours and a greater incidence of stroke symptoms for middle-age to older adults, even beyond other risk factors. Interestingly, the researchers did not find any link between short sleep periods and stroke symptoms in overweight and obese participants.
Still, the connection between short sleep and strokes is worthy of great attention from the medical community and general public. I agree with the Alabama study’s lead author, Megan Ruiter, PhD., who said, “The results of the Alabama study provide a strong argument for increasing physician and public awareness of the impact of sleep as a risk factor for stroke symptoms, especially among persons who appear to have few or no traditional risk factors for stroke.”
It looks like the medical community is taking this message to heart. Another study announced in late July is going on at the Alberta Health Services and the University of Calgary. There, Dr. Patrick Hanly of the university’s Hotchkiss Brain Institute is leading a study to learn more about the physiological connection between sleep apnea and stroke—specifically, the brain’s blood flow response in people with and without sleep apnea.
For the study, participants with sleep apnea stay overnight in the sleep laboratory at Calgary’s Foothills Medical Centre, where their breathing and cardiovascular responses are continuously monitored while they sleep. The next day, their brain blood flow response to reduced oxygen levels is assessed while they are awake. Then, the participants receive supplemental oxygen during sleep for two weeks, and are tested again to see if their cerebral defense mechanisms have improved. The researchers are also studying people without sleep apnea to see if their cerebral defense mechanisms function better than in those with sleep apnea. Hanly and team’s theory is that it is the lack of oxygen, or hypoxia, that people with sleep apnea experience during sleep that impairs the body’s normal defense mechanisms in the brain. A better understanding of this connection will lead to better prevention and treatment strategies.
I applaud the work of the Alabama and Calgary researchers. It’s time we all wake up to the health benefits of more–and better—sleep.
For more information, read the University of Alabama at Birmingham study, “Under 6 Hours of Sleep Tops Risks for Stroke in a Low-risk Population.”
In early June, the University of Alabama at Birmingham released the results of a study that regularly sleeping less than six hours a night significantly increases the risk of stroke symptoms in middle-age to older adults who are of normal weight and at low risk for obstructive sleep apnea (OSA). That’s worth repeating: Less than six hours of sleep per night increases the risk of strokes in adults of normal weight and not at risk for OSA.
It seems that under six hours of sleep per night is the critical variable, but why? Let’s take a look at the study. The University of Alabama researchersfollowed 5,666 people for up to three years who had no history of strokes or stroke-like symptoms, transient ischemic attacks (when blood flow to the brain stops for a brief period causing stroke-like symptoms), or high risk for OSA at the start of the study.
For a period of three years, the researchers followed and studied the subjects’ first stroke symptoms, stroke risk factors, depression symptoms, demographic information and other various health behaviors. What they found was—after adjusting for body-mass index (BMI)—there was a strong association between daily sleep periods of less than six hours and a greater incidence of stroke symptoms for middle-age to older adults, even beyond other risk factors. Interestingly, the researchers did not find any link between short sleep periods and stroke symptoms in overweight and obese participants.
Still, the connection between short sleep and strokes is worthy of great attention from the medical community and general public. I agree with the Alabama study’s lead author, Megan Ruiter, PhD., who said, “The results of the Alabama study provide a strong argument for increasing physician and public awareness of the impact of sleep as a risk factor for stroke symptoms, especially among persons who appear to have few or no traditional risk factors for stroke.”
It looks like the medical community is taking this message to heart. Another study announced in late July is going on at the Alberta Health Services and the University of Calgary. There, Dr. Patrick Hanly of the university’s Hotchkiss Brain Institute is leading a study to learn more about the physiological connection between sleep apnea and stroke—specifically, the brain’s blood flow response in people with and without sleep apnea.
For the study, participants with sleep apnea stay overnight in the sleep laboratory at Calgary’s Foothills Medical Centre, where their breathing and cardiovascular responses are continuously monitored while they sleep. The next day, their brain blood flow response to reduced oxygen levels is assessed while they are awake. Then, the participants receive supplemental oxygen during sleep for two weeks, and are tested again to see if their cerebral defense mechanisms have improved. The researchers are also studying people without sleep apnea to see if their cerebral defense mechanisms function better than in those with sleep apnea. Hanly and team’s theory is that it is the lack of oxygen, or hypoxia, that people with sleep apnea experience during sleep that impairs the body’s normal defense mechanisms in the brain. A better understanding of this connection will lead to better prevention and treatment strategies.
I applaud the work of the Alabama and Calgary researchers. It’s time we all wake up to the health benefits of more–and better—sleep.
For more information, read the University of Alabama at Birmingham study, “Under 6 Hours of Sleep Tops Risks for Stroke in a Low-risk Population.”
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