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Why some people die in their sleep - study
Some people die in their sleep because of a cumulative loss of cells in the part of the brain that commands breathing, the results of a new study indicate.
A team of researchers at the University of California, Los Angeles, set out to investigate why some people die in their sleep. They looked at the mechanism behind central sleep apnoea, which most commonly affects people over the age of 65.
Sleep apnoea is a condition in which breathing is disrupted during sleep. The most common type is obstructive sleep apnoea, which occurs when the throat is so narrow, it is partially or completely blocked. This can be caused by, for example, weight gain or alcohol consumption. The brain will signal the sleeper to arouse and resume breathing, so the sleeper will fight for breath until they wake up.
"Unlike obstructive sleep apnoea, in which a person stops breathing when their airway collapses, central sleep apnoea is triggered by something going awry in the brain’s breathing centre", said Professor Jack Feldman of UCLA.
Professor Feldman's team had already pinpointed a specific region of the brain as the 'command post' for breathing in mammals. They called it the preBotzinger complex (preBotC) and identified a small group of preBotC neurons (a type of cell) responsible for issuing breathing commands.
This time, the research team studied the role of preBotC neurons in issuing these commands during sleep. They also looked at what would happen if these brain cells were destroyed.
They injected adult rats with a specific compound that killed more than half of these essential neurons. The rats' breathing patterns were then monitored for five days. The results were dramatic.
"We were surprised to see that breathing completely stopped when the rat entered REM (rapid eye movement) sleep, forcing the rat to wake up in order to start breathing again. Over time, the breathing lapses increased in severity, spreading into non-REM sleep and eventually occurring when the rats were awake as well", said one of the researchers, Dr Leanne McKay.
The scientists believe that the findings are relevant to the human brain because all mammals' brains are organised in a similar way.
"Our research suggests that the preBot complex contains a number of neurons that we lose as we age. We speculate that our brains can compensate for up to a 60% loss, but the cumulative deficit of these brain cells eventually disrupts our breathing during sleep", Professor Feldman explained.
The researchers believe that many of these cases may go undetected as when elderly people, who were otherwise healthy, die in their sleep, the cause of death is often recorded as heart failure.
Details of their findings are published in Nature Neuroscience.
Some people die in their sleep because of a cumulative loss of cells in the part of the brain that commands breathing, the results of a new study indicate.
A team of researchers at the University of California, Los Angeles, set out to investigate why some people die in their sleep. They looked at the mechanism behind central sleep apnoea, which most commonly affects people over the age of 65.
Sleep apnoea is a condition in which breathing is disrupted during sleep. The most common type is obstructive sleep apnoea, which occurs when the throat is so narrow, it is partially or completely blocked. This can be caused by, for example, weight gain or alcohol consumption. The brain will signal the sleeper to arouse and resume breathing, so the sleeper will fight for breath until they wake up.
"Unlike obstructive sleep apnoea, in which a person stops breathing when their airway collapses, central sleep apnoea is triggered by something going awry in the brain’s breathing centre", said Professor Jack Feldman of UCLA.
Professor Feldman's team had already pinpointed a specific region of the brain as the 'command post' for breathing in mammals. They called it the preBotzinger complex (preBotC) and identified a small group of preBotC neurons (a type of cell) responsible for issuing breathing commands.
This time, the research team studied the role of preBotC neurons in issuing these commands during sleep. They also looked at what would happen if these brain cells were destroyed.
They injected adult rats with a specific compound that killed more than half of these essential neurons. The rats' breathing patterns were then monitored for five days. The results were dramatic.
"We were surprised to see that breathing completely stopped when the rat entered REM (rapid eye movement) sleep, forcing the rat to wake up in order to start breathing again. Over time, the breathing lapses increased in severity, spreading into non-REM sleep and eventually occurring when the rats were awake as well", said one of the researchers, Dr Leanne McKay.
The scientists believe that the findings are relevant to the human brain because all mammals' brains are organised in a similar way.
"Our research suggests that the preBot complex contains a number of neurons that we lose as we age. We speculate that our brains can compensate for up to a 60% loss, but the cumulative deficit of these brain cells eventually disrupts our breathing during sleep", Professor Feldman explained.
The researchers believe that many of these cases may go undetected as when elderly people, who were otherwise healthy, die in their sleep, the cause of death is often recorded as heart failure.
Details of their findings are published in Nature Neuroscience.
Sleep apnoea usually jolts people awake
SLEEP APNOEA
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