Bad news for extreme exercise addicts. Excessive strenuous exercise can weaken your immune system. At least, that’s what a 2023 study that analyzed more than 4,700 post-exercise body fluid molecules taken from firefighters suggests.
This can be a problem for workers who have consistently physically demanding jobs that require intense fitness training, such as first responders and athletes.
“Very healthy people may be more susceptible to viral respiratory infections immediately after strenuous exercise.” said Ernest Nakayas, a biomedical scientist at Pacific Northwest National Laboratory (PNNL); “One reason may be that inflammatory activity to fight infection is reduced.”
while it’s still there strong evidence Suggests that healthy people need moderate physical activity May benefit the immune system In the long term, what happens to the immune system immediately after intense exercise is controversial.
There is little reliable evidence to support the claim that strenuous exercise increases the risk of opportunistic infections. previous the study have noticed The self-reported number of upper respiratory tract infections in athletes after intense exercise was compared to a control group. It is unclear whether these are correlated or causal.
So Nakayasu and his colleagues tested the plasma, urine, and saliva of 11 firefighters before and after a strenuous 45-minute workout carrying up to 20 kilograms (44 pounds) of equipment through hilly terrain.
“We wanted to take a closer look at what’s going on inside the body and see if we could detect the dangers of fatigue at an early stage.” explained Christine Burnham-Johnson, a bioanalytical chemist at PNNL; “It could potentially reduce the risk of strenuous exercise for first responders, athletes, and military personnel.”
There’s no doubt that exercise can do wonders for our health, from boosting our mood to strengthening our immune systems. However, like previous studies, this study also found that firefighters show signs of immune suppression in their bodies as they work hard.
Among the physical changes that are expected to help our bodies maintain the increased hydration, energy and oxygen needed for exercise, we observed a decrease in molecules involved in inflammation. Along with this, Opiorphina peripheral vasodilator.
What these changes ultimately mean for the short-term function of the immune system is unclear, but researchers have some ideas.
”[Opiorphin] “It may increase blood flow to muscles and improve oxygen and nutrient delivery during exercise therapy,” the research team said. written in their paper.
“The decrease in inflammatory molecules observed in saliva after exercise may represent an adaptive mechanism that improves gas exchange in response to increased cellular oxygen demand.”
Changes were also seen in the participants’ oral microbiomes. Scientists believe this is due to an increase in antimicrobial peptides found in firefighters’ mouths after strenuous activity, perhaps to compensate for immunosuppression, but this conclusion is uncertain. contested.
“However, this increase in antimicrobial peptide had no effect on inhibition.” Escherichia coli It will grow,” Nakayasu and others said. elaborate“Suggests that there are limits to the ability of oral antimicrobial peptides to prevent host infection.”
That said, other scientists believe that some of the changes observed are not signs of immunosuppression, but ratherEnhanced state of immune surveillance and immune regulation”.
Although within-subject comparisons mitigated the effects of small sample size, firefighters experience unique exposure to pollutants during fires, which may also alter immune responses.
Additionally, the researchers cautioned that because the study only included healthy, active men, further research with the broader community is needed to confirm the findings.
However, considering previous studies, “there is evidence supporting a relationship between physical demands and increased incidence of respiratory infections,” Nakayasu and the research team said. conclude.
This research military medical research.
A previous version of this article was published in November 2023.
