December 7, 2022

expert reaction to impact of cold weather on human health

The Met Office and UKHSA have issued a cold weather alert across England from Wednesday 7 December.

Dr Laurence Wainwright, Departmental Lecturer at the Smith School of Enterprise and the Environment, University of Oxford, said:

“In recent years a sizable body of data has emerged indicating that cold snaps can pose a range of challenges in terms of our mental health – especially for those with an underlying psychiatric disorder.  

“For those with an illness such as Major Depressive Disorder or Bipolar Disorder, periods of unusually cold weather can exacerbate and worsen symptoms. There are complex interactions at play here between socio-economic factors (e.g. does a house have proper heating), the type of medication being taken, support systems and care in place, and the severity of the illness and current phase (mood disorders are cyclical in nature). 

“Another group of people – most of whom are otherwise healthy – can get a form of depression known as Seasonal Affective Disorder which comes only during the darker, cold months and then vanishes again when it gets warmer and brighter. 

“For the general population, cold weather can have a minor to moderate impact on mental health. It seems there are three key factors at play here, with feedback loops exacerbating the impact of each. 

“First, withdrawing from some of the regular activities that give our life structure and keep us healthy. When it is very cold outside (and also inside for many of us struggling with energy bills), we are more likely to rug up indoors and batten down the hatches. While we don’t hibernate like many other mammals do, humans tend to take things slower and withdraw somewhat when it is colder. For instance, when the alarm goes off for our usual morning jog, the temptation to stay snuggled up under warm blankets rather than face the freezing cold and pitch black can be irresistible.  Or we may ignore that text message from a friend asking to meet up at the pub and instead stay curled up on the couch. Lessening both exercise and social interaction have a tangible impact on our mental health.  

“Second is shorter days and a lack of bright light. Cold weather, limited sunlight hours and gloomy skies often go hand in hand. There are fascinating interactions here between the circadian rhythm of the body – our internal clock that plays an important role in all body systems – exposure to light, levels of vitamin D, and two chemicals in the body called melatonin, and serotonin. We may find ourselves sleeping longer – but paradoxically feeling more tired than usual – struggling to get out of bed, finding it harder to concentrate, and even having a slightly lower mood than usual. 

“Third are the psychological impacts of dealing with what lies ahead. While a lucky few of us can fly off somewhere warm for the winter, most of us will have to endure many months of chilly weather and short days. The mental fatigue and sense of dread that some people experience in the realisation that winter has only started and it will be over 100 days until the birds sing in the springtime can be challenging.”

Prof Andrew Charlton-Perez, Professor of Meteorology, University of Reading, said:

“Even relatively moderate cold temperatures have an impact on ill-health in the UK, but more extreme temperatures like those forecast in the coming days can have widespread effects so it’s really important to follow government advice and check in on more vulnerable people. Unlike heatwave conditions, a small but significant impact of cold weather on the health of the population can last for a few weeks. Long-range predictions made in November showed some indication of a milder winter for the UK and Europe overall, but with higher risk of the kind of cold outbreaks driven by changes to atmospheric flow patterns that are behind the cold temperatures over the latter part of this week and the weekend.”

Dr Raquel Nunes, Assistant Professor in Environmental Change and Public Health at Warwick Medical School, said:

“Cold temperatures increase risks to human health due to thermal stress and have direct impacts on human health both in terms of mortality and morbidity, as well as other physical and mental effects, affecting overall wellbeing.

“Extreme cold poses a direct impact on health which is translated into an increased probability of respiratory and cardiovascular diseases, falls and injuries, as well as hypothermia with older people, those chronically ill, children and homeless as those more at risk from feeling the impacts of extreme cold temperatures. Additionally, beside individual factors, other characteristics influence how cold-health risks are distributed. As an example, housing and economic factors (e.g. fuel poverty, lack of housing insulation, thermally inefficient housing), as well as behavioural factors (e.g. inability to stay warm) play an important role. As a result, in order to reduce the health impacts of extreme cold, strategies and actions focusing on improving the wider determinants of health (e.g. fuel poverty, social isolation), making health improvements (e.g. diet, well-being, falls and injuries in old age) need to be developed and implemented.”

Dr Emma Lawrance, Mental Health Lead, Institute of Global Health Innovation, Imperial College London, said:

“Cold homes pose a mental health risk – in fact, the risk of severe mental distress doubles for people who haven’t been affected by mental illness, and triples for people who have previously been at risk. This is unequally felt by the poorest in society. With the cost-of-living crisis, it is further a source of on-going mental stress for the growing numbers of people who have to choose between heating their homes or eating. Appropriate action, such as government investment to insulate homes, could reduce the direct impact of cold homes on people’s mental health and wellbeing, reduce inequalities and support a safer climate – itself vital for good health into the future.”

https://www.metoffice.gov.uk/public/weather/cold-weather-alert/?tab=coldWeatherAlert&season=normal

Declared interests

For all other experts, no reply to our request for DOIs was received.