JAMA Network Open: analysis of 4.2 million clinic visits links extreme heat to slightly lower blood pressure
In an analysis of over 4.2 million summer clinic visits, short-term extreme heat coincided with slight drops in systolic and diastolic pressure, most clearly in adults 65 and older.
According to ad-hoc-news.de, an analysis published in JAMA Network Open, covering more than 4.2 million summer clinic visits, found that short-term extreme heat was accompanied by slight declines in systolic and diastolic blood pressure ad-hoc-news.de
ad-hoc-news.dead-hoc-news.deOpen source ↗. The effect was clearly stronger in adults aged 65 and older and in people with hypertension, whether or not they were taking medication, than in younger or normotensive comparison groups.
Blood pressure and heat: what the data show
The largest drops were measured on the day of heat exposure and on the day before, and then diminished. The study authors stressed that the long-term cardiovascular consequences remain unclear and require further research.
The German Hypertension League and the German Heart Foundation note that heat can both lower and raise blood pressure. In people taking antihypertensive drugs, heat-related vasodilation sometimes causes a disproportionate drop. Thomas Voigtländer of the Heart Foundation says that at a systolic value below 100 mmHg a medical consultation is advisable. Angela Thiel-Bodenstaff of Homburg University Hospital cautions against stopping such drugs independently and says adjustments should be made only after consulting the treating physician.
Related studies and a pharmacy survey
A cross-sectional study in BMC Geriatrics was conducted from June to August 2026 at a cardiology outpatient clinic of Zonguldak University Hospital in Türkiye. It included 680 patients aged 65 and older (mean age 71.3 years, 48.1% women). Of the participants, 75.9% had at least two heat-related symptoms, 52.1% experienced worsening of symptoms, and 82.4% had inadequate cooling. Worsening was statistically associated with heart failure, longer indoor heat exposure and frailty, among other factors ad-hoc-news.de
ad-hoc-news.dead-hoc-news.deOpen source ↗.
A study in Heart, led by Dr. Alexandra Schneider at the Institute of Epidemiology II of Helmholtz Munich, found that temperature extremes can trigger heart failure or stroke. Heat affects blood coagulation, raises blood viscosity and increases the risk of thrombosis, while cold raises blood pressure.
A survey by the market research institute Aposcope, commissioned by Apotheken Umschau, covered about 1,000 pharmacists and pharmaceutical-technical assistants. Of them, 66% had observed an increase in heat-related complaints over the past three years, especially cardiovascular problems and dizziness. About 90% rated the risk of medication-related complications for older people in summer heat as high, and 85% did so for cardiovascular patients. Nearly 70% considered mail-order the riskiest transport route for temperature-sensitive drugs. Prof. Ulrike Holzgrabe of the University of Würzburg states that medicines should generally be stored at 15 to 25 degrees, and refrigerated products must be kept in the refrigerator.
