[pliftkl]

Ah - but the population of people-travel-days is also probably quite high, and while it doesn't impact a "whole population", it impacts a subset of the population frequently enough to be a comparable order of magnitude to the population as a whole.

(Potentially bad) back of envelope calculations follow: 1. The entire US population of 330 million is impacted by a 1 hour shift twice per year (of which one shift is probably more impactful than the other to sleep health). 2. On a typical year, there are about 1 billion airline passengers in the US alone (domestic plus inbound/outbound international). This counts everyone on a flight as one passenger. Let's assume that people take on average 2 legs in one day (probably a slightly high estimate). That's 500 million people, but we should halve that again since people have outbound and inbound trips. So we're down to 250 million people being impacted by travel. 3. Some of the travel is in the same time zone, but other travel spans many time zones (inbound international flights or transcontinental flights). We can call that a wash, though we could probably get to actual data if I weren't being lazy. I'd also argue that the travel is going to be much more disruptive to sleep schedules since in addition to the actual time zone shifts, travelers have to deal with early departures and late arrivals. 4. Many of the people who travel are being counted multiple times here, so we don't have a true collection of 250 million people impacted, but it's not clear that 1 person experiencing jet lag 10 times should only be counted once, since this is a recurring 1-2 day issue. 5. We're not orders of magnitude off here in terms of people-days impacted by normal travel vs the great DST debate.