Article Text

Download PDFPDF

Stable or fluctuating temperatures in winter: which is worse for your lungs?
  1. Kin Bong Hubert Lam
  1. Correspondence to Dr Kin Bong Hubert Lam, Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Oxford OX3 7LF, UK; hubert.lam{at}

Statistics from

The ratification of the Paris Agreement in 20151 signifies a worldwide consensus on climate change has been reached. The Intergovernmental Panel on Climate Change has warned as global warming intensifies, extreme weather events (such as heat waves, droughts, floods) will become more frequent and more severe.2 Indeed in the UK, within the first few months of 2018, there has already been a cold wave between late February and early March (with maximum temperature 8°C–12°C below average for the time of year)3 and an unusually warm week in April (which saw a rise of almost 20°C from 6°C–7°C in the previous week).4 That heat waves or cold spells could lead to excess deaths has been documented in previous studies5–7 and is probably unquestionable. However, even in the absence of extreme temperature episodes, exposure to so-called non-optimum ambient temperatures has shown to be associated with elevated risks of morbidity and mortality.8–10 A recent study of over 74 million deaths from 13 countries has found most of the temperature-related short-term (days to weeks after the exposure) mortality displacement could in fact be attributed to moderate hot and cold temperatures, rather than extreme heat (temperature higher than 97.5th percentile) or cold (lower than 2.5th percentile).

Many of these previous studies have used mean daily temperature as the exposure metric. The fact that health impact has been observed in both colder and hotter temperatures suggests there is adaptation to usual temperatures and unexpected fluctuations in temperature may be more relevant. Temperature variability, as it is known, …

View Full Text

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Linked Articles