With the frigid winter months fast approaching, it’s important to remind your patients with hypertension to keep a close eye on their blood pressure. Research shows that blood pressure is generally highest in winter and lowest in summer. Several studies in recent decades bear that out.

The Link Between Cold Weather and Hypertension: A Sampling of Clinical Evidence

A 1993 study in the Journal of Hypertension examined blood pressure in 96 individuals aged 65 to 74 years. The researchers found that both systolic and diastolic blood pressure were elevated during winter. In fact, they observed a fourfold increase in participants with blood pressures of 160/90 in winter compared with summer.1


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A 2009 study in JAMA Internal Medicine found that systolic blood pressure decreased with increasing temperature, with an 8.0-mm Hg decrease separating the lowest and highest temperature quintile. The study, which included subjects 65 years and older, found that changes in blood pressure were greatest in those 80 years and older. The researchers noted that careful monitoring of blood pressure and antihypertensive treatment could reduce risk in periods of extreme cold.2

A 2018 study in Nature found that the risk of hypertension and other cardiovascular events is greater in winter. The researchers stated that, at the individual patient level, low values measured in summer do not indicate low risk in winter. Instead, only low values in winter should be considered a true measure of low cardiovascular risk.3

A 2021 study in Nature likewise found seasonal variations in blood pressure. The researchers identified an elevation in daytime blood pressure in winter and nighttime blood pressure in summer. They attributed the former to cold temperatures and the latter to physical discomfort and poor sleep quality. The winter elevation of daytime blood pressure, they noted, is likely associated with the increased incidence of cardiovascular events in the winter months compared to other seasons.4

How to Help Your Patients Monitor Their Blood Pressure in Winter

A 2013 study in the International Journal of Health Sciences offered explanations for why a significant increase in systolic and diastolic blood pressure is observed during winter. Among those reasons5:

  • Colder temperatures
  • Lack of physical activity
  • Seasonal variation in noradrenalin, catecholamine, and vasopressin
  • Reduced vitamin D intake
  • Serum cholesterol 

The investigators noted, however, that a number of simple precautions could be taken to reduce the risk of hypertension in winter. They include ensuring adequate indoor heating, wearing protective clothing, regular exercise, and a healthy diet.

References

1. Woodhouse PR, Khaw KT, Plummer M. Seasonal variation of blood pressure and its relationship to ambient temperature in an elderly population. https://pubmed.ncbi.nlm.nih.gov/8301109/ J Hypertens. 1993 Nov;11(11):1267-1274

2. Alpérovitch A, Lacombe JM, Hanon O, et al. Relationship between blood pressure and outdoor temperature in a large sample of elderly individuals. https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/414703. Arch Intern Med. 2009;169(1):75080. doi: 10.1001/archinternmed.2008.512

3. Modesti PA, Rapi S, Rogolino A, Tosi B, Galanti G. Seasonal blood pressure variation: implications for cardiovascular risk stratification. https://www.nature.com/articles/s41440-018-0048-y. Hypertens Res. 41: 475-482

4. Narita K, Hoshide S, Kario K. Seasonal variation in blood pressure: current evidence and recommendations for hypertension management. https://www.nature.com/articles/s41440-021-00732-z. Hypertens Res. 44: 1363-1372

5. Fares A. Winter hypertension: potential mechanisms. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3883610/. Int J Health Sci (Qassim). 2013 Jun; 7(2): 210–219

This article originally appeared on The Cardiology Advisor