Scientists discovered that two types of exercise—intense workouts and steady-paced workouts—can help repair damage to blood vessels caused by early heart disease. They tested this on mice that were fed an unhealthy diet to mimic human heart disease. After 12 weeks of exercise, both types of workouts improved the mice’s blood vessel health by reducing harmful substances in their bodies. The intense workouts worked slightly better than steady exercise. This research suggests that getting regular exercise, especially intense workouts, might help people prevent or slow down heart disease in its early stages.

The Quick Take

  • What they studied: Whether two different exercise programs could fix damage to blood vessels in mice with early-stage heart disease
  • Who participated: Laboratory mice genetically designed to develop heart disease, divided into groups: some that didn’t exercise, some that did intense interval training, and some that did steady-paced exercise. About 6 mice per group.
  • Key finding: Both types of exercise improved blood vessel health and reduced harmful inflammation in the body. Intense interval training worked slightly better than steady exercise at fixing the blood vessel damage.
  • What it means for you: Regular exercise, especially intense workouts, may help prevent or slow heart disease in its early stages. However, this was tested in mice, so more research in humans is needed before making major changes to your exercise routine.

The Research Details

Researchers used laboratory mice that were genetically modified to develop heart disease similar to humans. They fed these mice an unhealthy, high-fat diet for 12 weeks to trigger early heart disease. Then they divided the mice into three groups: one group continued without exercise, one group did high-intensity interval training (short bursts of intense activity), and one group did moderate-intensity continuous training (steady-paced exercise). Both exercise programs lasted 12 weeks. The researchers also had a healthy control group of normal mice that didn’t develop heart disease.

Throughout the study, scientists measured several things: how much the mice weighed, their cholesterol and fat levels in the blood, markers of stress and damage in their cells, and how well their blood vessels could relax and function properly. They also looked at specific molecules in the body that control inflammation and cell damage.

This research design is important because it allows scientists to test exercise effects in a controlled way before testing in humans. By comparing two different exercise types side-by-side, researchers could see which approach works better. The study looked at the actual biological mechanisms—the specific molecules and pathways—that explain why exercise helps, not just whether it helps.

This study was published in Scientific Reports, a respected scientific journal. The research was carefully controlled with specific mouse groups and measured multiple health markers. However, because this was done in mice rather than humans, the results may not directly apply to people. The sample size was relatively small (6 mice per group), which is typical for laboratory studies but means results should be confirmed with larger studies.

What the Results Show

Both exercise programs successfully reduced body weight in the mice with heart disease, bringing them closer to the weight of healthy mice. More importantly, both types of exercise improved how well the blood vessels could relax and function—a key sign of heart health.

The exercise programs reduced harmful substances in the mice’s bodies that cause inflammation and cell damage. These include molecules that trigger inflammatory responses and oxidative stress (a type of cellular damage). Both HIIT and MICT lowered these harmful markers significantly.

The study found that both exercise types reduced a protein called PCSK9, which is known to contribute to heart disease. By lowering this protein, the exercise helped protect the blood vessels. Additionally, both programs improved cholesterol and fat levels in the blood—important risk factors for heart disease.

However, high-intensity interval training (HIIT) showed slightly better results than moderate-intensity continuous training (MICT) at improving blood vessel function and reducing inflammatory pathways. This suggests that more intense exercise might offer additional benefits for people with early heart disease.

The exercise programs improved several other health markers in the mice. Antioxidant levels (substances that protect cells from damage) increased in both exercise groups. The mice’s lipid profiles improved, meaning their cholesterol and triglyceride levels became healthier. The exercise also reduced markers of oxidative stress, which is cellular damage caused by harmful molecules. These improvements suggest that exercise helps the body protect itself from the damage that leads to heart disease.

Previous research has shown that exercise is good for heart health, but this study provides new details about how it works. It confirms that both intense and steady exercise help, but it’s one of the first studies to show that intense interval training might have a slight edge in repairing blood vessel damage. The study also identifies specific molecular pathways that exercise affects, which helps explain the ‘why’ behind exercise’s benefits for heart disease.

This research was conducted in mice, not humans, so the results may not directly apply to people. The sample size was small (6 mice per group), which is common in laboratory studies but means results should be confirmed with larger studies. The study only looked at early-stage heart disease in mice, so it’s unclear if these results apply to more advanced heart disease in humans. The mice were on a controlled diet and exercise program, which is different from real-world conditions where people have varying diets and exercise habits. Finally, the study lasted 12 weeks in mice, which is a relatively short timeframe compared to human disease development.

The Bottom Line

Based on this research, regular exercise—especially high-intensity interval training—appears to help prevent or slow early-stage heart disease by improving blood vessel health. However, these findings are from mouse studies and need to be confirmed in humans. If you’re interested in heart disease prevention, talk to your doctor about an exercise program that includes both steady-paced activity and some higher-intensity workouts. Moderate confidence in these findings due to the animal model used.

This research is most relevant to people concerned about heart disease prevention, especially those with risk factors like high cholesterol, obesity, or a family history of heart disease. It’s also relevant to people in early stages of heart disease who want to know if exercise can help. People with existing heart conditions should consult their doctor before starting any new exercise program, especially high-intensity training. This research is less directly applicable to people without heart disease risk factors, though regular exercise is beneficial for everyone.

In the mouse study, improvements in blood vessel function and inflammation markers appeared after 12 weeks of exercise. In humans, similar benefits might take several weeks to months to develop, depending on fitness level and consistency. Some improvements in cholesterol and weight might appear within 4-6 weeks, while improvements in blood vessel function could take 8-12 weeks or longer.

Want to Apply This Research?

  • Track weekly exercise sessions, specifically noting the type (steady-paced vs. high-intensity intervals) and duration. Also track resting heart rate weekly, as improvements in heart health often show up as a lower resting heart rate over time.
  • Users could set a goal to include at least one high-intensity interval training session per week alongside regular steady-paced exercise. The app could provide guided HIIT workouts and help users gradually increase intensity over time.
  • Monitor resting heart rate, exercise consistency, and perceived energy levels over 8-12 weeks. Users could also track cholesterol levels if they have access to blood tests, as this is a key marker of heart health improvement. Set monthly check-ins to assess progress toward heart health goals.

This research was conducted in laboratory mice and has not been tested in humans. The findings suggest potential benefits of exercise for early-stage heart disease, but individual results may vary. Before starting any new exercise program, especially high-intensity training, consult with your healthcare provider, particularly if you have existing heart conditions, high blood pressure, or other cardiovascular risk factors. This information is for educational purposes and should not replace professional medical advice. Always seek guidance from a qualified healthcare professional before making significant changes to your exercise routine or health regimen.