Blood pressure, circadian systems, and exercise

According to the American Heart Association, cardiovascular disease accounted for nearly one million deaths in the U.S. in 2020. Heart disease and stroke alone are responsible for more deaths in the U.S. each year than cancer and Chronic Lower Respiratory Disease combined. And cardiovascular disease is costly, making up nearly 12 percent of total U.S. health expenditures between 2018 and 2019 at a cost of $407.3 billion. 

The Centers for Disease Control and Prevention notes that individuals can take action to reduce their risk of cardiovascular disease. Preventative measures include eating healthy, reducing alcohol consumption, stopping smoking, maintaining a healthy weight and exercising. 

Researchers at the Oregon Institute of Occupational Health Sciences study the physiology of exercise in relation to sleep and circadian health to understand the role of sleep and the circadian system in blood pressure reactivity to exercise.

Research Assistant Professor Leandro Campos de Brito recently received the prestigious American Heart Association's 2024 Career Development Award. The three-year, $230,814 award supports early career investigators exploring innovative questions or pilot studies that provide the data and training necessary for future success as a researcher.

Building on recent discoveries by Brito and colleagues Professors Steven Shea and Saurabh, the project will address two aims. The first aim will test the hypothesis that blood pressure reduction after exercise (below the levels observed before exercise, a beneficial phenomenon called post-exercise hypotension) is affected by the circadian system and that recovery can be impaired to a greater extent in the morning due to physiological processes that naturally attenuates blood pressure reduction at that time. For the second aim, de Brito will investigate the effects of sleep loss on the neural mechanisms that control blood pressure reactivity during exercise in the morning in individuals with hypertension.

A better understanding of the body's time-specific cardiovascular responses to exercise could provide more insights into the mechanisms involved in adverse cardiovascular events that occur in the morning. Additionally, Brito's study will elucidate how the circadian system modulates blood pressure mechanisms post-exercise and shed light on whether overnight sleep loss exacerbates blood pressure reactivity during exercise in people with a heightened risk of cardiovascular disease.

"We know exercise is an important factor in reducing the risk of cardiovascular disease," Brito said. "But it can also pose risks for individuals with cardiovascular disease. This project aims to study the roles of sleep and the circadian system underlying blood pressure reactivity to exercise."

Heart disease was responsible for nearly 20 percent of deaths in the U.S. in 2021. Exercise is but one of many preventative measures we can take to reduce the risk of cardiovascular disease. Long-term research conducted by Dr. Brito and colleagues can inform the conversation about how to maximize the benefits of exercise while minimizing the potential risks for those with cardiovascular disease.