This article is more than 5 years old. Information may no longer be current.

Moderately intense exercise decreases exhaled nitric oxide in inactive adults with asthma

Physically inactive adults with asthma who underwent a moderately intense exercise program experienced decreased levels of exhaled nitric oxide, according to study results.

“This study demonstrates that the inflammatory responses to a single bout of moderate-intensity exercise are influenced by habitual physical activity status in adults with asthma,” Hayley A. Scott, PhD, of the University of Newcastle in Australia, and colleagues wrote. “Exhaled nitric oxide, a surrogate marker of eosinophilic airway inflammation, was transiently decreased after exercise … , with the decrease in [exhaled nitric oxide (eNO)] strongly correlated with increases in circulating levels of the anti-inflammatory cytokine, interleukin-1ra.”

The investigators conducted a randomized, controlled, crossover trial in which 14 nonsmoking adults with asthma, aged 18 to 65 years, completed 30 minutes of moderately intense exercise on a treadmill, followed by 30 minutes of rest. A 4-week washout period was held between visits.

Participants had a venous blood sample collected and eNO was measured. Spirometry was performed before and 15 minutes after administration of 400 µg salbutamol.

Twenty minutes after bronchodilation, the participants underwent activity. Exhaled nitric oxide was measured at 5 minutes, 30 minutes, and at 1, 2, 4, and 24 hours after intervention, and blood samples were collected at 5 minutes, 2 hours, and 24 hours after intervention.

Among participants classified by a self-questionnaire as physically inactive (n = 6), eNO decreased by 4.8 ppb at 4 hours after exercise, while no significant changes were observed in active participants (n = 8) until an eNO increase of 3.8 ppb at 24 hours.

The researchers also reported an increase in blood neutrophils in the physically active group and a similar trend in the inactive group immediately after exercise (P = .052).

The small sample size and measurement of only moderate-intensity exercise were considered study limitations, the researchers said, warranting more investigation.

“Future studies are needed to establish which intensity and type of exercise produces the most favorable effects on airway inflammation in those with asthma,” the researchers wrote. “In addition, future studies should examine the long-term effects of exercise training on chronic inflammation in asthma.” – by Ryan McDonald

Disclosure: The researchers report no relevant financial disclosures.