Atrial Fibrillation, Stroke and Colder Temperatures


Compared to summer, the risk of ischaemic stroke increased by 10% in spring and 19% in winter. 



Cold Weather and Stroke Risk from Atrial Fibrillation

Until now it was unclear whether the risk of ischaemic stroke was higher in AF patients during cool seasons or on days with a lower temperature; The study investigated this issue in 28 ,559 new-onset AF patients from the “National Health Insurance Research Database” inTaiwan during 2000 to 2011.

The risk of ischaemic stroke was higher among the months with a lower average temperature. In addition, the incidence of ischaemic stroke was highest in winter and lowest in summer .

Compared to summer, the risk of ischaemic stroke increased by 10% in spring and 19% in winter. Stroke risk did not differ significantly between summer and autumn.

“Our study shows a clear association between temperature and risk of ischaemic stroke in patients with AF,” said Dr Chao. “Risk may increase in cold weather because of the pro-coagulant status.”

When the average temperature was below 20 °C the risk of ischaemic stroke significantly increased compared to days with an average temperature of 30 °C. “This may be because of the increased coagulability and plasma viscosity,” said Dr Chao.

The results imply that the interaction between humans and the environment may play an important role in AF-related stroke and remind us that cool climate may be an underrated issue for health which deserves more attention.

Read more:

Cold weather linked to increased stroke risk in atrial fibrillation patients

European Society of Cardiology 

August 30, 2015

Source of Image: Edvard Munch, 1899, Winter


Dr. Parker’s Commentary

Note that this was done in Taiwan, where the average temperature differences were not that extreme.

As a resident of Alaska, one could only expect that this is more of a problem here.

Does this mean more anti-coagulant use should be prescribed for  AFib patients in the winter?

Or  perhaps prescribing spending the winter in southern latitudes?


 “You can’t get too much winter in the winter.”

-Robert Frost-


Link: Atrial Fibrillation, Stroke and Blood Thinners 


Dr. Parker is a 68 year old heart attack survivor and cardiac psychologist.He is an Honors graduate of Stanford University with forty years of clinical experience. Dr. Parker is available for consultation on heart matters. Contact him at heartcurrents(at)