Sleep apnea and memory

If your sleep is disrupted by an irregular breathing pattern known as sleep apnea, research suggests that as you snooze, you lose...brain cells that is. Sleep experts have long known that persons who are restless by night from sleep apnea are befuddled by day, and they assumed that such foggy-headedness resulted from fatigue. Investigators in Kentucky beg to differ, however, after they discovered that periodic lack of oxygen in rodents wreaks havoc on the brain's memory center called the hippocampus.

Dr. David Gozal and his colleagues studied ratty little brains and found that intermittent hypoxia (IH)--the episodic drop in blood oxygen levels that occurs during the prolonged respiratory pauses of sleep apnea--causes apoptosis or death of neurons involved in memory and learning. On the other hand, sustained low oxygen levels such as those that might occur in rats residing in Leadville, CO or in a Tibetan monastary, causes protective adaptive changes that spare these vital brain areas.

These research findings suggest that untreated and prolonged sleep apnea may lead to permanent changes in brain functioning. There is good news, however, from the Southern rodents. Those animals who agreed to undertake the rat-sized equivalent of a one hour daily walk in the park were protected against the destructive effects of IH on their brains.

Bad news, on the other hand, from an analysis of the effects of diet on rat brains exposed to IH. The rats who ate a high-fat, refined-carbohydrate diet (as in American convenience foods) were dazed in their mazes, and the inability to figure a route out was magnified if this lousy diet was paired with IH. The combined effect of IH and fast food on rats prompted Dr. Gozal to call such double trouble "a major disaster for the brain."