Our bodies naturally adapt to cold, dark winter conditions. Scientists think the rise of warm houses and bright lights has baffled our immune systems
Turn down that thermostat! Photograph: Alamy
It’s time to turn down the heating and switch off the lights – all this cosiness is making us ill. At least that sounds like the advice from new research which suggests the “endless summer” we have created in our homes could be playing havoc with our health, and even causing early deaths.
Scientists now believe that up to a quarter of our genes are seasonal – and that those controlling our immunity become more active in cold months than during summer days, helping us to fight off diseases such as flu.
Tyler Stevenson, a behavioural neurobiologist at the University of Aberdeen, is one of the authors of a review looking at how seasonal changes affect humans, livestock and ecosystems. He explains that while there has been a lot of research into how disruptions to our natural daily cycles – such as shift work – can affect our health, we know very little about the ways our bodies are affected by disruptions to seasonal changes.
“There are examples of detrimental effects and we want to generate more interest so we can understand outcomes in more detail.”
“Things like jet lag, which disrupt daily time, can increase the possibility of someone getting sick or having an emotional or cognitive shift,” he says.
“When the outside environment is seasonal but your internal environment is constant you have a disconnect. That can increase the probability of different diseases or pathological states.”
One problem, he says, is that while our bodies can adapt to environmental changes, the shift in our lifestyles brought on by the industrial revolution was too abrupt. And it could take our bodies a long time to catch up.
Stevenson says his paper is a call for more research, but in the meantime should we be turning down the central heating? The senior lecturer already does. “It’s easy to say we should all live in tune with nature, but that’s not really feasible in the modern day. My wife keeps the house at 17C. That’s better for your pocket book and, most likely, it would be better for your health.”
But, he says, keeping light pollution out of your home is a better bet because we have more of an understanding of how disruptive it can be to our daily rhythms and immune systems. Which sounds like a perfect reason to stop work earlier during the winter months. Turn off the light on your way out.