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 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, reduce the likelihood of developing certain diseases, and help to improve disease outcomes by controlling infections more effectively,” explained Rebekah Hunt, a Ph.D. candidate at the University of Houston and first author of the study.
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.
(Newswise/ AM)
