Go On, Take A Nap — It's Good For Avoiding the Pseudo-Science in this Yahoo Story

2015-02-10 00:00:00 +0000

Yahoo, that trove of pseudo-scientific health news, today brought us a story about napping: Go On, Take A Nap — It’s Good For Your Immune System.

The article starts out with the bold assertion that

“Naps may be good for more than helping you stay alert and focused during the day — according to a small new study, they could also be a boon to the body’s immune system.”

How did they arrive at that conclusion? The study put 11 healthy males in a sleep lab and put them through two sleep interventions. After a normal night’s sleep (defined as eight hours), the first intervention consisted of sleep restriction, where subjects only slept from 2 to 4 AM, followed by a normal day of staying awake. Subjects returned to the lab some time later for the second intervention, which consisted of sleep restriction as in the previous study, followed by two 30-minute naps during the following day.

Levels of norepinephrine and interleukin-6, hormones that are know to be influenced by sleep, or lack thereof, were measured throughout. Sure enough the study found these hormone levels were indeed influenced by the sleep patterns. The naps effectively normalized hormone values.

This is where the Yahoo reporting turns to story telling, and the story gets really muddy. Queue this gem from one of the study authors:

“Napping may offer a way to counter the damaging effects of sleep restriction by helping the immune and neuroendocrine systems to recover.”

Note the operative keyword here: may. The authors are drawing conclusions beyond the data: instead of saying “napping after sleep restriction CORRELATES with improved hormone profiles for norepinephrine and interleukin-6,” which he would have been fine to say, he says something to the effect of “napping after sleep restriction CAUSES improved hormone profiles for norepinephrine and interleukin-6”.

It just gets worse from here. Segue some third-party expert to opine:

The new findings add to a body of research on sleep and the immune system, which seems to show a sort of bidirectional relationship between the two, says Philip Gehrman, PhD, CBSM, an assistant professor in the Department of Psychiatry at the University of Pennsylvania and member of the Penn Sleep Center, who was not involved in the new study. “Some aspects of the immune response promote better sleep, while others disrupt sleep,” Gehrman tells Yahoo Health.

Some aspects of the immune response promote better sleep, while others disrupt sleep?

That’s completely backwards from what the study actually did! The study manipulated sleep patterns and examined levels of two immune-system-related hormones. In effect, the study said A (sleep patterns/napping) correlates with B (hormone levels).

The good doctor Gehrman seems to say that B causes A!

He goes on to state that

“One theory is we have that system in place because it gets us to sleep more when we’re sick, and that it helps our immune system.”

Again, he’s suggesting that B causes A, which is nothing more than a theory, not remotely supported by the study in question.