NIAID Scientists Investigate How Exercise Exacerbates Symptoms of Rare Disease

People with a rare disease called mastocytosis must do their cardio with caution.

NIAID staff do a warm-up before taking a run or brisk walk.

Mastocytosis occurs when a person has too many mast cells(link is external), a type of white blood cell. Mast cells normally play a healthy role by releasing granules filled with chemicals that cause inflammation, which allows immune cells and other helpful particles in the blood to reach a site of infection or injury more easily. However, having too many mast cells can lead to the release of too much of these inflammatory chemicals, causing symptoms such as flushing, severe itching, abdominal pain, diarrhea, and fainting due to a sudden drop in blood pressure.

Scientists have reported that physical factors including exercise can worsen mastocytosis-related symptoms. To better understand the relationship between exercise and these symptoms, scientists led by NIAID researcher Hirsh Komarow, M.D., explored whether physical exercise triggers the release of mast-cell chemicals in people with mastocytosis. Dr. Komarow is a staff clinician in the NIAID Laboratory of Allergic Diseases.

Dr. Komarow and colleagues focused on two chemicals released by mast cells, histamine and tryptase. In people with mastocytosis, blood-serum levels of these chemicals rose significantly after physical exercise, supporting the hypothesis that physical activity can induce mast cells to release inflammatory chemicals. The increase in histamine and tryptase levels after exercise was significantly greater in people with mastocytosis than in healthy individuals. The scientists also found that the post-exercise increase in blood levels of these chemicals was associated with a worsening of mastocytosis-related symptoms.

Dr. Komarow advises that people with mastocytosis consult their physicians about how to manage any worsening of symptoms during and after exercise, noting that medication such as an antihistamine could potentially help. In addition, Dr. Komarow recommends that people with mastocytosis know how to self-administer epinephrine to treat anaphylaxis, should it occur.

The results of this study were recently published in The Journal of Allergy and Clinical Immunology: In Practice