But is it not also true that cognitive function declines if you work more than 25 hours a week for those _under_ 40 also? In fact, isn't it true that cognitive

But is it not also true that cognitive function declines if you work more than 25 hours a week for those _under_ 40 also? In fact, isn't it true that cognitive function declines after only 10 minutes of focussing on a single problem! My main wonder: Why did they limit the study to persons over 40 only? Oh, well, I can always take solace in "Why Most Published Research Findings Are False" John P. A. Ioannidis Published: August 30, 2005 http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0020124 http://journals.plos.org/plosmedicine/article?id=10.1371/jou... and "We have an epidemic of deeply flawed meta-analyses" by the same author: http://retractionwatch.com/2016/09/13/we-have-an-epidemic-of-deeply-flawed-meta-analyses-says-john-ioannidis/ http://retractionwatch.com/2016/09/13/we-have-an-epidemic-of... and the original paper "he Mass Production of Redundant, Misleading, and Conflicted Systematic Reviews and Meta-analyses" at: https://www.milbank.org/quarterly/articles/mass-production-redundant-misleading-conflicted-systematic-reviews-meta-analyses/ https://www.milbank.org/quarterly/articles/mass-production-r...