Different levels of exercise can actually significantly increase or decrease your chances of catching a respiratory infection, says professor Mike Gleeson from Loughborough University.
While regular moderate exercise can reduce the risk of catching cold-like infections, prolonged strenuous exercise, such as marathons, can make an individual more susceptible. This is a topical area of research in the year of the Olympics, says Gleeson, who will be speaking at the Association for Science Education (ASE) Conference on Jan. 6, on behalf of the Society for General Microbiology and the British Society for Immunology.
Upper respiratory tract infections (URTIs) are acute infections that affect the nose, throat and sinuses, and include the common cold, tonsillitis, sinusitis and flu. Viruses that circulate in the environment usually cause URTIs. While we are constantly exposed to these viruses, it is the status of our immune system that determines whether we succumb to infection or not. Exercise can have both a positive and negative effect on immune function, combined with genetics and other external factors like stress, poor nutrition and lack of sleep. Collectively these factors determine an individuals susceptibility to infection.
Gleeson explains why the exercise factor is an interesting one. If you have a tendency to be a couch potato then you probably have an average risk of catching an infection typically two to three URTIs per year. Research shows that those undertaking regular moderate exercise (e.g. a daily brisk walk), can reduce their chance of catching a respiratory infection, such as a cold, by up to almost a third. This effect has been shown to be the result of the cumulative effect of exercise leading to long-term improvement in immunity. Conversely, in periods following prolonged strenuous exercise, the likelihood of an individual becoming ill actually increases. In the weeks following a marathon, studies have reported a 2-6 fold increase in the risk of developing an upper respiratory infection, says Gleeson. The heavy training loads of endurance athletes make them more susceptible to URTIs and this is an issue for them as infections can mean missing training sessions or underperforming in competitions.
The major players in this immune regulation are immune cells called Natural Killer (NK) cells which are important weapons in the fight against viral infections. NK cells recognise viral-infected cells as foreign invaders and force them to commit suicide. During moderate exercise the activity of NK cells is enhanced, whereas stressful endurance activities such as marathons can turn down NK cell activity. These changes are tightly regulated by stress hormones and other immune cells, explains Gleeson.
There is a clear take-home message from our current understanding of the link between exercise and immune function. Moderate exercise has a positive effect on the immune system. So to keep colds at bay, a brisk daily walk should help - its all about finding a happy medium, Gleeson says.
Â
A Helping Hand: Innovative Approaches to Expanding Hand Hygiene Programs in Acute Care Settings
July 9th 2025Who knew candy, UV lights, and a college kid in scrubs could double hand hygiene adherence? A Pennsylvania hospital’s creative shake-up of its infection prevention program shows that sometimes it takes more than soap to get hands clean—and keep them that way.
Broadening the Path: Diverse Educational Routes Into Infection Prevention Careers
July 4th 2025Once dominated by nurses, infection prevention now welcomes professionals from public health, lab science, and respiratory therapy—each bringing unique expertise that strengthens patient safety and IPC programs.
How Contaminated Is Your Stretcher? The Hidden Risks on Hospital Wheels
July 3rd 2025Despite routine disinfection, hospital surfaces, such as stretchers, remain reservoirs for harmful microbes, according to several recent studies. From high-touch areas to damaged mattresses and the effectiveness of antimicrobial coatings, researchers continue to uncover persistent risks in environmental hygiene, highlighting the critical need for innovative, continuous disinfection strategies in health care settings.