High Physical Activity Tied to Poor Asthma Control in Females

In a study of 526 adolescents and young adults who were asked about how much they exercised, researchers found that compared with moderate physical activity, high physical activity levels were linked with poorer asthma control in females, but not males.

“It is important to remember that the high level of activity means nothing extreme — in our patient material every third girl exercised that much. Still, we uncovered these results, and with such a distinct gender difference,” Ludvig Lövström, from the Department of Medical Sciences, Clinical Physiology, Uppsala University, Sweden said in a news release.

The findings, which were published online November 19 in Respirology, suggest that healthcare professionals should pay extra attention to the treatment of asthma in highly active females.

A group of 408 patients diagnosed with asthma, aged 10 to 34 years, answered questions concerning frequency and/or duration of physical activity and undertook the Asthma Control Test, spirometry, methacholine challenges, and exhaled nitric oxide measurements to measure their asthma control.

A group of 118 age- and sex-matched subjects who did not have asthma, randomly chosen from the population registry, served as the control group and also answered the questions.

Physical activity levels were determined from a two-part questionnaire that asked, “How often do you usually exercise so much that you get out of breath or start sweating?” (frequency) and “How many hours a week do you usually exercise so much that you get out of breath or start sweating?” (duration).

Three levels of physical activity were defined for both frequency and duration: high (≥4 times a week), moderate (1 – 3 times a week) and low (once a month or less) frequency, and high-level (≥4 hours a week), moderate (1 – 3 hours a week), and low (about half an hour or less each week) duration.

Dr Lövström and colleagues found that frequently vs moderately active females had an odds ratio of 4.81 (95% confidence interval, 2.43 – 9.51) of having an Asthma Control Test score of less than 20, whereas no such effect was found in males (odds ratio, 1.18; 95% confidence interval, 0.61 – 2.30).

They also found that highly active females experienced asthma attacks more often than their moderately active peers during the 3 months before the study, despite similar levels of local or systemic inflammation and bronchial responsiveness.

The researchers say it is unclear whether this is related to airway diameter or differing perceptions, or whether airways in females with asthma are just more predisposed to asthma attacks.

This cross-sectional study was part of a project run within the framework of an industry–academy collaboration on Minimally Invasive Diagnostics for Asthma and Allergic Diseases (MIDAS). The MIDAS study was financially supported within the framework of an academy–industry collaboration initiated by the Swedish Governmental Agency for Innovation Systems, where Aerocrine AB and Thermo Fisher Scientific Immunodiagnostics were partners and cofinanced the program. One coauthor is an employee of Thermo Fisher Scientific. No other relevant financial relationships were disclosed.

Respirology. Published online November 19, 2015. Abstract