Do you take allergy pills before hitting the gym to avoid seasonal sniffles? Study warns you may want to think twice | Health

Taking antihistamines before exercise may impact your fitness gains. Research suggests that antihistamines can blunt the beneficial effects of exercise by reducing muscle blood flow and limiting physiological processes like muscle perfusion. Here’s what you need to know about the study published on May 30 in the Journal of Applied Physiology. Also read | Why your workout isn’t working: 7 common gym mistakes and how to fix them

What is histamine and why does it matter?

The molecule histamine – often linked to seasonal allergies like runny noses, scratchy throats, and itchy eyes – also influences exercise performance. The University of Oregon study underscores its beneficial role in aerobic activity and exercise recovery, showing that blocking histamine at high levels interferes with fitness gains.

“In exercise, it actually seems to be playing a very similar role of facilitating our adaptation to stress,” said John Halliwill, a professor of human physiology at the University of Oregon and an author on the study. He and colleagues found that when histamine is blocked, aerobic fitness improvements were slashed in half.

Histamine also seems to boost the response of certain genes during exercise. When histamine is blocked, about a quarter of those 3,000 or so genes aren’t amplified. That means fewer new proteins get produced by muscles as they recover from exercise, and those proteins likely play key roles in fitness gains, like the ones measured in the study.

More about the study

The researchers compared the improvements in a group of 16 men and women participating in a six-week biking regimen. Participants pedalled on stationary bikes three to four times a week over the course of the study. One group received a dose of antihistamine medication before each training session, while the other group took a placebo. 

Then, researchers compared how the groups’ bodies adapted. When it came to their actual performance — how hard they could bike — the placebo group saw about twice the improvement of the histamine-blocker group. Improvements in blood flow were also significantly higher in the placebo group.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.