Home / News
Rebekah Hunt

Long Beach, Calif. (April 5, 2024)—Exercising at moderate intensity for just 15 minutes may be all that is needed to boost immunity by increasing levels of natural killer (NK) cells. Researchers will present their work this week at the American Physiology Summit in Long Beach, California. The Summit is the flagship annual meeting of the American Physiological Society (APS).

NK cells are a type of white blood cell and are a first-line defense in the immune system. Their primary job is a “search and destroy” mission to eliminate infected cells—including cancerous cells—in the body. NK cells are called “natural killers” because they can identify and kill dangerous cells without having previous exposure to the abnormal pathogens.

Previous research has found that exercise increases levels of NK cells in the bloodstream, which can provide a period of heightened immunity. “Mobilizing more of these cells can lead to protecting the body against infections, reduces the likelihood of developing certain diseases, and helps to improve disease outcomes by controlling infections more effectively,” explained Rebekah Hunt, a PhD candidate at the University of Houston and first author of the study.

someone rides a stationary bike while breathing into a tube. Three observers watch measurements on a screen nearby.
Researchers study volunteers as they exercise at moderate intensity.

In this new study, a group of 10 volunteers between the ages of 18 and 40 exercised on a stationary bicycle for 30 minutes at moderate intensity. The researchers drew the volunteers’ blood before the cycling session and again at the 15- and 30-minute marks. The research team found NK cell levels in the blood increased after 15 minutes of exercise but did not reach higher levels after 30 minutes of cycling.

This potential boost to the immune system may be particularly notable for people with cancer, as NK cells are known to kill tumor cells. Exercising for mere minutes before seeing an increase in NK cells can be encouraging for people who have trouble finding time to exercise or prefer shorter workouts, as “our results don’t point to a clear advantage in terms of increasing NK cells in the bloodstream by exercising for longer than 15 minutes at a moderate intensity,” Hunt said.

NOTE TO JOURNALISTS: The American Physiology Summit will be held April 4–7, 2024, in Long Beach, California. To schedule an interview with the researchers, conference organizers or presenters, or to request abstract 2061, “Can just 15 minutes of moderate-intensity exercise mobilize cytotoxic NK cells into circulation?” contact APS Media Relations or call 301.634.7314. Find more highlights from the meeting in our Summit Newsroom.

Physiology is a broad area of scientific inquiry that focuses on how molecules, cells, tissues and organs function in health and disease. The American Physiological Society connects a global, multidisciplinary community of more than 10,000 biomedical scientists and educators as part of its mission to advance scientific discovery, understand life and improve health. The Society drives collaboration and spotlights scientific discoveries through its 16 scholarly journals and programming that support researchers and educators in their work.

Related Content

Contact Us

For questions, comments or to share your story ideas, email us.