We've supposedly lost an average of 2.3 hours of sleep a night since 1910 — a figure that doesn't survive a look at the historical data actually available.

noli's read

The "2.3 hours lost since 1910" figure circulates widely online, but no sourced study confirms it, and the best available data points the other way. A systematic review of objectively measured sleep duration (polysomnography and actigraphy, 168 studies, 1960-2013) finds no significant decline over that period; a UK analysis using time diaries (1974-2015) actually finds a 43-minute average increase; and a comparison across 23 countries finds sleep duration stable or slightly rising in the large majority of cases, with a decline being the exception rather than the rule. The idea that "sleep isn't additive, it's an amplifier" of everything else (training, mood, patience) is a reasonable metaphor, consistent with what's otherwise known about how sleep loss affects cognition and mood — but it doesn't rest on any specific measurement in this post, and it doesn't need the wrong historical figure to stay valid. The shock statistic should be set aside; the general intuition (protecting your sleep matters more than you'd think) still stands without it.

the sources

No named source held this one up — that absence is part of the verdict.