Many people take antihistamines to combat their allergy symptoms, but some recent research is suggesting that they could actually have a detrimental effect on muscle recovery. The research done at the University of Oregon is suggesting that having antihistamines in the body can block certain genes that impact muscle recovery following a workout.

We take antihistamines to of course block what goes haywire with the histamine receptors, which when aggravated by things like pollen and dander are what causes allergy symptoms like runny nose, itchy eyes, sneezing, etc.

After we finish a workout we might feel like our work is done, but in actuality the body is still hard at work. Around 3,000 different genes take part in the recovery process which includes increasing the blood flow, relaxing the blood vessels, and building muscles. But if anything gets in the way of this it can affect your ability to recovery and ultimately gain muscle.

Antihistamines seems to

To test this theory out the researchers had 16 men and women between the ages of 23 to 25 do some knee extension exercises for them. They were all done at about 60 percent of their peak power. The researchers had half of the participants take an antihistimine ahead of time choosing two different types. They had them take 540 mg of fexofenadine, which is an antihistamine that treats hay fever and is found in drugs like Mucinex and Allegra. They also had them take 300mg of ranitidine, which is found in Zantac and has some antihistamine effect when taken to treat acid in the stomach.

The researchers monitored what happened during the exercise in two different ways. For one thing they took biopsies of their thigh muscles both before and three hours after the exercise was done. And then during the actual workout they also kept track of their blood flow, blood pressure, and heart rate.

What they found was that the antihistamines did not have an immediate effect on the workout at all, but that three hours after the workout a significant amount of gene expression was blocked by the antihistamines. They found it to be about 88 percent of the 795 genes, which is crazy.

Basically with those genes blocked it wasn’t possible to for them to function at their highest possible outcome, so the body could not recover at full speed from the workout.

However this does not mean that you should never take your antihistamines again. According to the lead study author Steven Romero:

“We need to do a training study in which we put people on histamine blockers and see if their adaptations to exercise training are as robust or diminished,” Romero said. “I also wouldn’t be surprised if we can demonstrate that some responses to exercise training do become blunted if you take high doses of histamine blockers.”