Intriguingly these 40 minutes of sleep seem to be getting overwhelmingly off at the front end of our sleep — that is, respondents to the MCTQ survey were going to sleep 40 minutes later and getting up at the same time. Roenneberg and his team trigger that this has to do with the knocked 40-minute decrease in sunlight exposure that has taken place over the same period of time. The posit strongest biological wake-up cue, the matching for our brains and bodies to function properly, remains sunlight, and even the most well-lit interiors fall far short in corresponding exterior light intensity