In the 1920s, a pair of sociologists set out to study “the interwoven trends that are the life of a small American city” at a time of rapid change.
In their subsequent book about Muncie, Indiana (which they anonymised as “Middletown”), they wrote that the community was divided by time as well as class.
At 6am, the lights were going on in working-class households because their jobs generally began between 6.15 and 7.30am (when they weren’t on night shifts), while the “business class” households remained slumbering until later.
These different working rhythms became political in 1925 when a deadlock emerged over whether the city should adopt “daylight saving time”, which would mean longer light on summer evenings.
READ MORE
The working-class early risers argued they would lose sleep, while the businessmen urged the change “because of golf” and the need to deal with businesses on the east coast.
The competing demands for leisure and business on the one hand, and of our body clocks on the other, have not gone away over the ensuing century. But scientists have learned a lot more about what happens to our health when we prioritise the former over the latter.
Budget 2027: Does this giveaway budget have potential banana skins that might lie ahead for the Government?
In short: nothing good. Many researchers now agree that daylight saving time can interfere with our circadian rhythms. But there are much more dangerous ways to meddle with our biological clocks, the worst of which is to work at night.
It is a myth that night-shift workers can become nocturnal over time. According to the book Life Time by professor of circadian neuroscience Russell Foster, studies suggest that 97 per cent of night shift workers remain synchronised to daytime, which means they have to sleep when their bodies are primed to be awake, and vice versa.
There are consequences for blood pressure and the immune system. The correlations with cancer are so clear that night work has been classed as “probably carcinogenic to humans” by the World Health Organisation’s International Agency for Research on Cancer.
[ Maynooth-led sleep research will examine links with mental healthOpens in new window ]
Even if you don’t work overnight, evidence suggests that just working against your “chronotype” can be bad for your health. One recent study from Finland looked at what happened to people who gave information about whether they were morning people or “night owls” in 2012 when they were in their mid-40s.
Over the following 12 years, those with evening chronotypes were more likely to end up on disability pensions, even after adjusting for socio-economic factors. One possibility, according to the researchers, is that “traditional working times interfere significantly with the sleeping preferences of late chronotypes, leading to social jet lag”.
But while the prevalence of night work has declined gradually in the US since Middletown was written, there is still a class divide when it comes to work that tramples over your body clock. According to research published this year, most US night workers have no more than a high-school education.
More broadly, the pandemic-induced shift towards remote work has been a bigger boon for white-collar workers (who already had more flexibility over their hours) than anyone else.
[ What ‘smart’ watches get wrong and right when tracking the quality of your sleepOpens in new window ]
In Europe, for example, managers have the highest levels of autonomy according to 2024’s vast European Working Conditions Survey, with 40 per cent able to adapt their working hours within certain limits, and 19 per cent having full control over their schedules. In contrast, workers at the bottom end of the pay scale continue to have little control: nearly 80 per cent have schedules set entirely by their employers.
It is possible that advances in automation will eventually do away with the need for humans to work against their body clocks. Already, some logistics companies are beginning to experiment with “lights-out night shifts” in which robots work overnight alone, setting aside those orders that require human assistance until the morning shift arrives.
Self-driving trucks, meanwhile, could cover long highway stretches overnight, saving the “final mile deliveries” for human drivers to do in daytime.
Such a transition would be economically challenging for workers – not least since night-shift work usually pays a premium – but could have huge benefits for human health. It would require careful navigation by policymakers with an eye on science, inequality and the future.
Yet US president Donald Trump sounds much more like a voice from the past. His latest intervention into the “politics of time” is to push for daylight saving time to be made permanent, arguing that it would be good for people who would “like to play golf a little bit without having to run home after 14 holes”. – Copyright The Financial Times Limited 2026
