A new study found that people with high blood pressure who used a smartphone app and an at-home monitor were able to lower their blood pressure. Hello Heart is a program that allows people to track their blood pressure, weight, and physical activity and provides advice on how to manage blood pressure.

Half of all adults in the United States have high blood pressure, but only about a quarter of them have it under control. It can be a difficult condition to manage, especially if people only have their blood pressure measured in the doctor’s office, where it can be higher or lower (due to a condition known as masked hypertension) than it is at home. However, it is risky and puts people at risk of heart disease and stroke.

Doctors and researchers are interested in digital health approaches to managing blood pressure that provide people with resources to track the condition at home because they have the potential to be widely distributed. The Hello Heart program includes a blood pressure monitor that sends readings to an app automatically. The app tracks trends and automatically recommends strategies for users to improve their blood pressure through diet and exercise.

Over 85 percent of people with stage two hypertension, a condition that puts people at risk for heart disease, had lower systolic pressure after one year of using the program, which measures the amount of force blood puts on artery walls while the heart is squeezing. According to the study, which was published in the journal JAMA Network Open, they remained at lower levels for three years.

The app was also effective for people with less serious conditions: after a year, approximately half of people with elevated blood pressure had reductions, as did approximately 70% of people with stage one hypertension. People who used the app more frequently saw greater benefits and had lower blood pressure.

This Hello Heart program analysis included over 28,000 participants. People with certain employer-based health insurance plans and a high blood pressure diagnosis were asked if they wanted to participate. They ranged in age from 43 to 58, and the majority lived in higher socioeconomic areas.

Notably, the study followed participants for up to three years; the authors claim it is the first long-term study of a digital blood pressure management program. Following participants over time allows researchers to ensure that the impact of a program like this isn’t just transient and that it can help people manage their blood pressure in the long run.

“This is the first peer-reviewed, published study that reports the long-term experience of a digital health application for blood pressure management,” study author Alexis Beatty, a cardiologist and associate professor at the University of California, San Francisco, said in a statement.

Hello Heart is currently only available through employer wellness programs — it is included as part of some companies’ health benefits. People who do not work for a company that offers Hello Heart are unable to use it, but it is still possible to monitor blood pressure at home without the use of an app.

Despite the promising results, the authors point out that the majority of those who participated in the program were middle-aged and not low-income. It’s difficult to say whether the app would work as well in groups of people who are more likely to have serious blood pressure complications, such as the elderly or those without health insurance, the researchers wrote in their study.