Aging typically brings on a decline in deep non-rapid eye movement (NREM) or "slow wave sleep," and the characteristic brain waves associated with it, including both slow waves and faster bursts of brain waves known as "sleep spindles."

Youthful, healthy slow waves and spindles help transfer memories and information from the hippocampus, which provides the brain's short-term storage, to the prefrontal cortex, which consolidates the information, acting as the brain's long-term storage.

"Sadly, both these types of sleep brain waves diminish markedly as we grow old, and we are now discovering that this sleep decline is related to memory decline in later life," said Joseph Winer, a doctoral student in Walker's lab.

Another deficiency in later life is the inability to regulate neurochemicals that stabilize our sleep and help us transition from sleep to waking states. These neurochemicals include galanin, which promotes sleep, and orexin, which promotes wakefulness.

"The American College of Physicians has acknowledged that sleeping pills should not be the first-line kneejerk response to sleep problems," Walker said. "Sleeping pills sedate the brain, rather than help it sleep naturally. We must find better treatments for restoring healthy sleep in older adults, and that is now one of our dedicated research missions."

Also important is the question of quantity versus quality. "Previously, the conversation has focused on how many hours you need to sleep," Mander said. "However, you can sleep for a sufficient number of hours, but not obtain the right quality of sleep."

"Indeed, we need both quantity and quality," Walker was quoted as saying in a news release.