The laboratory of Michael J. Joyner, M.D., is interested in how humans respond to various forms of physical and mental stress during activities such as exercise, hypoxia, standing up and blood loss.

Dr. Joyner and his team study how the nervous system regulates blood pressure, heart rate and metabolism in response to these forms of stress. They are also interested in how blood flow to muscle and skin responds to these stressors. These responses are studied in young healthy subjects, healthy older subjects and people with conditions such as heart failure.

Finally, Dr. Joyner is personally interested in the role of integrative approaches in science as a powerful tool to integrate and critique data from reductionist approaches.

Focus areas
Convalescent plasma. Dr. Joyner is leading a national program sponsored by the U.S. Government to coordinate the collection and distribution of COVID-19 convalescent plasma for the treatment of individuals with severe or life-threatening disease.

Blood flow during exercise. Blood flow to exercising skeletal muscle can increase 50 to 100 times above resting values. Dr. Joyner's group is interested in the mechanisms that drive this increase in flow.

Blood pressure regulation. Blood pressure is regulated by complex interactions among the nervous system, heart and blood vessels. Dr. Joyner's group is interested in how these interactions are affected by the sex and age of the subject.

Blood glucose regulation. Glucose levels in the blood are tightly regulated to guard against hypoglycemia. Dr. Joyner and his collaborators are studying the novel idea that sensors in the body that respond to hypoxia also control blood glucose.

Breathing in heart failure. In heart failure, breathing during exercise can be excessive. Dr. Joyner and his collaborators have novel data suggesting that signals from the exercising muscle are driving ventilation in heart failure.

Physiology of elite athletes. Elite athletic performances are experiments in nature on the limits of human physiology. Dr. Joyner uses data from real-world competitions to understand the limits of human physiology.

Cognitive impairment and heart disease. Cognitive impairment is associated with risk factors for cardiovascular disease. Dr. Joyner and his collaborators are studying how aging and fitness influence brain blood vessels in humans.