Changing time backward and forward by and hour is simultaneously jarring for everybody, so it provides some statistical means of estimating how changing sleep h

Changing time backward and forward by and hour is simultaneously jarring for everybody, so it provides some statistical means of estimating how changing sleep habits affects people. But most people hopefully lead variable enough lives that for them there will be various reasons why they sleep differently though the year. Traveling to a different timezone, getting up early for an exceptional meeting or appointment, I had to get up early this week to go hell my in laws with something... this is normal life, it's just not synchronized for all of us. The only difference with respect to health impact is that spring forward / fall back is the one time we can see it in a population.