I am a person who loves to work late into the night. I’m busy during the day, with phone calls and text messages and assignments and meetings, so my productivity and focus is lower than it should be. Once the sun sets and everyone goes to bed, a peaceful calm descends, creating a serene environment for reading, working, studying, whatever it might be.

The problem with working late is the waking up part. If you start work in the afternoon, then fine. But, if like me, you still need to wake up relatively early in the morning to head to work, then you’ve probably suffered from sleepiness or even dozed off from time to time.

We already know that sleep is imperative to our health, energy, thinking, and other cognitive abilities, but cheating on a full night’s rest is easy to do because it seems like the consequences will be short term: “I’ll be tired tomorrow. I can deal with it.” But it looks like that’s the wrong answer.

I first heard of a possible link between Alzheimer’s and lack of sleep many years ago. Since then, I’ve heard unscientific anecdotes about how many people in seniors’ care homes with dementia had demanding careers and senior positions with lots of responsibility. There was already speculation that years of just a few hours’ sleep may have caught up to them.

Then I saw this from the New York Times: Sleeping Too Little in Middle-Age May Raise Dementia Risk, Study Finds. It’s the first large study to draw such a strong connection between sleep and memory loss:

It followed nearly 8,000 people in Britain for about 25 years, beginning when they were 50 years old. It found that those who consistently reported sleeping six hours or less on an average weeknight were about 30 percent more likely than people who regularly got seven hours sleep (defined as “normal” sleep in the study) to be diagnosed with dementia nearly three decades later.

“It would be really unlikely that almost three decades earlier, this sleep was a symptom of dementia, so it’s a great study in providing strong evidence that sleep is really a risk factor,” said Dr. Kristine Yaffe, a professor of neurology and psychiatry at the University of California, San Francisco, who was not involved in the study.

If you take pride at how much you can accomplish on such little sleep, read this — now. The article details how the study was conducted and how other variables that could have impacted the results were removed, so you can make up your own conclusions.

It’s a scary read, but better to come across it now than when it’s too late.