Rachel Salas, a neurologist and expert on sleep disorders at Johns Hopkins Medicine, says, “If sleeping is important, that would suggest that dreaming is important.” (Johns Hopkins Medicine)

Michel Stevens of Harpers Ferry, W.Va., has been a chef for more than 35 years. It’s a profession that monopolizes her waking hours. Sometimes it infiltrates her sleeping ones, too.

“I dream up recipes in my sleep,” Michel wrote. “Often my dreamtime recipes come out somewhat better than my waking recipes. My husband, John, thinks I should write a cookbook called ‘Dream On: Adventures in Sleepcooking.’ ”

Over the last few days, I’ve shared stories of how aggravating dreams about work can be. But sometimes good things happen.

“As a computer engineer/programmer for over 40 years, sometimes my work does find its way into my dreams,” wrote Fred Myers of South Bend, Ind. “Occasionally, I’ll work out an approach to solving a problem in a dream, wake up, write it down, and then it actually pans out when I get to work. Very satisfactory.”

Sheri Bellow, a licensed psychologist from Crofton, Md., has had similar experiences.

“I can report that I wrote much of my doctoral dissertation while I slept,” Sheri wrote. “I’d be immersed for hours each day in research and writing, often stopping when I reached a stumbling block, uncertain of what my next step would be. At that point, I was generally exhausted and would sleep, waking later with my first thoughts containing the solution to my quandary. I learned the importance of keeping pen and paper nearby while I slept.”

Sleep: There’s a reason we spend a third of our lives doing it, even if we aren’t sure what that reason is.

“It must be important,” said Rachel Salas, a Johns Hopkins Medicine neurologist who studies sleep and treats sleep disorders. “And if sleeping is important, that would suggest that dreaming is important.”

But scientists aren’t sure exactly why.

“There are a lot of theories out there,” Salas said. “The bottom line is we just don’t know. There is some research suggesting that dreams are the brain processing or getting rid of unwanted memories, kind of consolidating memories as we’re sleeping.”

On a biological level, sleep cleanses the cerebrospinal fluid in which the brain and spinal column bathe. If the fluid doesn’t get cleaned, Salas said, there’s a higher risk for developing Alzheimer’s disease or dementia.

Great, another thing to worry about as we try in vain to drift off to sleep.

As for dreams, some scientists think they can play a role in creativity. “There’s some research showing that musicians have been inspired during their dreams and have actually composed music during sleep,” Salas said.

So maybe those job dreams aren’t so bad, though I guess it depends on the job and the dream.

Most of us dream about four to six times a night, even if we don’t remember those dreams when we wake up. Salas said research suggests that dreams about things that happened at work or home, or about people you know, occur during non-REM sleep, the type of sleep that accounts for about 75 percent of our slumber.

REM sleep is a deeper sleep, but one in which the brain goes into overdrive. Brain activity during REM sleep resembles that in a waking brain.

“Bizarre dreams, where we’re flying or talking to an alien and we believe it, those are more likely to be in REM sleep,” Salas said.

REM sleep — characterized by rapid-eye movement and increased heart rate and respiration — is also the setting for an unsettling condition known as REM behavioral sleep disorder.

“These people tend to be older — over 50 — and they start having these very vivid dreams, usually during REM sleep in the early morning, around 4 a.m.,” Salas said. “These people act out their dreams. In normal people our brain is kind of in check, otherwise we would all be acting out our dreams. These people, they lose that. They have violent dreams.”

Salas said one of her patients fractured his clavicle during an episode.

People who suffer from depression or anxiety tend to have higher incidents of nightmares, Salas said. Some patients who have unsettling dreams can benefit from integrative medicine therapies, such as hypnotherapy, meditation and mindfulness.

Dreams may not “mean” anything, except to a Freudian. Even so, Salas said that if a patient comes to her and describes dreams of choking, suffocating or drowning, “that’s actually a red flag in my mind. It could suggest that person maybe is not breathing correctly and may have sleep apnea.”

For the rest of us, work dreams may just be an inevitable, occasional nighttime visitor.

Talking in your sleep

Rachel Salas will be answering sleep-related questions from noon to 1 p.m. Thursday during a Facebook chat. Visit facebook.com/johns.hopkins.medicine.

Bye for now

Here’s what I’m dreaming of: vacation. I’m taking some time off to cleanse my cerebrospinal fluid. Look for me back in this space on July 31. Until then, sweet dreams.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/johnkelly.