Can Antihistamines Decrease Muscle Soreness?

I still shave/ wax my legs. Not as often as before, but I still try to keep them hair free.

Ever since my racing days, I've been making sure my legs are free of hair. Why is that so you should be asking?

In the event of a bike crash and the resulting abrasions, the wounds are easier to clean if there is no hair on the skin.  From time to time I need to take Clarityn (which is a relatively mild antihistamine) for my hives that result from the ingrown hair.

Easier to clean the wounds with no hair

I sometimes use Clarityn for mild allergies as well. Piriton (or chlorphenamine) is stronger, but it makes me very drowsy.

So I was surprised to read that taking a single dose of antihistamines can help lessen delayed onset of muscle soreness (or DOMs) after a hard workout.

After a hard workout, blood flow to your muscles remain elevated for a while. Histamines (part of your body's immune response) play a role in triggering this post exercise blood flow, which may be linked to inflammation and subsequent repair of muscle.

The researchers' aim was to investigate if blocking histamines with antihistamine medication would reduce post exercise blood flow, reduce inflammation and increase muscle damage and DOMs.

The subjects had to run downhill on a 10 percent grade for 45 minutes after taking the antihistamine medication (control group didn't take). Blood flow, inflammatory markers, pain sensitivity, perceived soreness and strength were measured for three days.

Results showed that blood flow to the legs was reduced by 29 percent an hour after exercise in the antihistamine group. There were however no differences in markers of inflammation.

Creatine kinase (used to determine muscle damage) levels were very different. This seems to supports the idea that blocking histamine receptors resulted in increased muscle damage.

The control group (didn't take medication) was 19.3 percent weaker the day after the hard workout compared to the group that took the antihistamines (7.8 percent weaker).

Before you rush to the nearest pharmacy to buy some Clarityn, do bear in mind that the results were a little more complex after you examine them closely.

This is very similar to what I wrote a few weeks earlier about the balance between recovery and adaptation.

The researchers themselves do not know exactly why this is so. It is possible that the antihistamine medication make you feel less pain and soreness (even if there was more damage in your muscles).

This makes antihistamines a double edged sword. They may make you more prone to muscle soreness even though you may not feel it.

If, however you want an edge to reduce next day soreness and strength loss when you have back to back races or games then taking antihistamines may help.

If you interfere with the recovery process to make yourself better soon (or recover faster), do you then risk delaying the repair or adaptation process? It is a short term versus long term trade off.


Reference

Ely MR, Romero SA et al (2016). A Single Dose Of Histamine-receptor Antagonists Prior To Downhill Alters Markers Of Muscle Damage Andd Delayed Onset Muscle Soreness. J Appl Physiol.
DOI: 10.1152/japplphysiol.00518.2016.