Research shows it’s not just how much you run, but how hard you go that plays a key role in improving health and performance.

Even small amounts of higher-effort activity added to your routine can make a meaningful difference.

When it comes to boosting performance and health, many runners tend to focus on frequency and duration of activity—for example, how many days a week you run , along with total weekly mileage . But there’s another variable that is just as important when it comes to progress and disease prevention: intensity .

A new study published in the European Heart Journal , looking at data from about 475,000 people, found those who incorporated vigorous physical activity into their regular routines were at the lowest risk of developing major chronic diseases.

“The main message from this research is that how hard you move matters, not just how much you move,” says the study’s principal investigator, Minxue Shen , PhD, professor and vice director of Xiangya School of Public Health at Central…