A low resting heart rate is often seen as a sign of good health, but now, a large study suggests that both very low and very high heart rates may be linked to an increased risk of stroke. The findings, presented May 6 at the European Stroke Organisation Conference 2026 in Maastricht, Netherlands, are based on data from nearly 460,000 people whose data is included in the UK Biobank, a large repository of health data from U.K. adults. On average, each person was monitored for 14 years, and researchers recorded more than 12,000 cases of stroke among the participants. "When we looked across the data, the lowest risk was in the middle, around 60 to 69 beats per minute, and increased at both ends," said first author Dr. Dexter Penn , a clinical fellow in cerebrovascular disease at Imperial College London. "The common idea is that the higher the heart rate, the higher the stroke risk, but the relationship isn't as linear as it seems," he told Live Science. The study included people ages 40 to 69.…