London - A cold day can make the heart fall.
But it could also cause potentially deadly changes in blood pressure.
Over time, these fluctuations raise the odds of dying by more than a third.
Lack of sunshine and inches of rain can also take their toll, the Glasgow University study found.
While the finding may seem odd, blood vessels near the surface are known to narrow in cold weather, to conserve heat, which increases blood pressure.
Blood pressure changes put the body under strain and increase the risk of heart attacks and strokes.
Researchers said doctors should note the weather when measuring a patient’s blood pressure. This would help them determine which patients are sensitive to it so they can adjust their treatment accordingly.
Heart expert Sandosh Padmanabhan made the link after comparing more than 40 years of blood pressure data on patients in the west of Scotland with meteorological data for the area.
It showed half of the patients were sensitive to drops in temperature, such as those that occur between summer and winter. A fall of around 10degC led to an increase in blood pressure of between 3mm and 6mm of mercury.
While this might not seem much, a change of just 2mm is enough to significantly affect the odds of fatal heart attacks and strokes.
Dr Padmanabhan said: “Every millimetre counts, that’s the important thing.”
Further analysis showed those whose blood pressure was sensitive to temperature were 35 percent more likely to die over the period studied. Lack of sunshine also increased blood pressure – likely due to dull days tending to be colder.
Rain was found to be damaging but the researchers attributed this to patients becoming stressed while struggling to the doctor’s in wet weather.
Heart attacks and strokes are more common in winter, but the study, published in the journal Hypertension, is the first to look at the issue in detail.
Dr Padmanabhan said doctors need to be aware of the link to properly manage blood pressure.
Otherwise a good reading in summer may lead to a patient missing out on potentially vital medicine. Similarly, someone who is known to be sensitive to temperature could pay extra attention to what they eat and how much exercise they do, to keep their heart healthy.
A Blood Pressure UK spokesperson said: “It is really interesting to know there may be a relationship between the weather and blood pressure; more research is needed to understand the potential mechanisms behind this.
“However until we can control the weather, we can still rely on more traditional ways of controlling our blood pressure, such as eating more fruit and vegetables, less salt and alcohol, and taking more exercise.
“Even if the sun isn’t shining, I would advise going for a brisk walk as a reliable way of reducing your long-term blood pressure.”
High blood pressure affects almost 16 million people in the UK. - Daily Mail