Quick Facts

• People with resting heart rates below 50 beats per minute had 25% higher stroke risk in 460,000-person study
• Optimal heart rate range for stroke prevention was 60-69 beats per minute, not as low as possible
• Fitness trackers may mislead users by encouraging excessively low heart rates

A major study of 460,000 people challenges the widespread belief that lower resting heart rates are always better for health. Researchers found that very low heart rates may actually increase stroke risk by 25 percent.

The Imperial College London study, presented at the European Stroke Organization Conference 2026, tracked participants for 14 years. During this period, 12,290 strokes occurred.

People with resting heart rates below 50 beats per minute had a 25 percent higher stroke risk compared to those in the optimal range. The lowest stroke risk occurred in people with heart rates between 60 and 69 beats per minute.

The U-Shaped Risk Pattern

The research revealed a U-shaped relationship between heart rate and stroke risk. Risk was highest at both extremes – very low and very high heart rates.

Participants with heart rates of 90 beats per minute or higher faced an even greater stroke risk increase of about 45 percent. The middle range of 60-69 beats per minute proved safest.

“Very low heart rates could be associated with reduced blood flow to the brain by prolonging the relaxation phase between heartbeats,” said lead author Dr. Dexter Penn from Imperial College London.

Fitness Tracker Concerns

The findings raise questions about fitness tracker messaging. Many devices and apps encourage users to lower their resting heart rates as much as possible.

Harvard’s Dr. Wasfy warns that while low heart rates often indicate fitness, they can sometimes cause dizziness or fatigue. This may result from aging electrical nodes in the heart or faulty signal transmission.

Fitness trackers also face accuracy limitations. Arm movement, sweat, skin tone and watch fit can impact heart rate measurements. Medical experts note these devices “are not always 100 percent accurate” and can create “false positives” that increase health anxiety.

What This Means for You

A normal resting heart rate ranges from 60 to 100 beats per minute. Athletes and young adults often have lower rates without health problems.

If your heart rate consistently falls outside the 60-69 range, experts recommend consulting a doctor. However, a single low reading without symptoms typically poses no concern.

Professor Alastair Webb, study co-author, said resting heart rate “deserves greater attention in cardiovascular risk assessment.” The research suggests treating fitness tracker numbers as guides, not absolute health measures.

The study authors plan further research to determine whether heart rate directly causes stroke risk or reflects underlying health conditions.

Read more: Why Your Low Resting Heart Rate Might Not Be As Healthy As You Think