Conventional wisdom has it that over the last 50 years sleep duration has declined in parallel

with the increasing prevalence of obesity,

suggesting that an epidemic of sleep loss is associated

with the epidemic of weight gain. Now we have triple-digit streaming, TV channels,

smartphones, and tablets to keep us entertained well into the night. The hurry and excitement of modern

life is quite correctly held to be responsible for much of the insomnia.

Concluded one medical journal editorial,

but that was an editorial published in 1894.

Are we really sleeping that much less?

It's 1905. Sleep duration in shoulder and adoles adolescents has declined by a little over an hour

a night.

However, child labor wasn't outlawed until 1938, though, and so part of the explanation

may be due to the exhaustion of sweating it out in the mines, farms, and factories in

the early part of the last century.

Since 1970, youth sleep duration has only declined about 15 minutes per night,

and it's not clear sleep duration in adults has changed much at all. Based on 168 studies of

objective measurements of sleep duration instead of just self-report, sleep duration in adults,

objective total sleep time hasn't changed much since 1960.

Since 2003, average sleep duration in the United States may have even gone up.

Now, of course, just because we don't have evidence that there's been a growing epidemic

of sleep deprivation, that doesn't necessarily mean we're getting enough sleep.

Maybe we weren't getting enough sleep 50

...