The Impact of Exercise Intensity on People with Asthma

If you have asthma, you may hesitate to exercise for fear of triggering an asthma attack. However, studies have shown that exercise can actually improve asthma symptoms. But how does exercise impact inflammation in people with asthma?

A recent clinical trial aimed to answer this question. The study randomized physically inactive adults with asthma to one of three groups: a control group with no intervention, a moderate exercise group (45 minutes of moderate exercise), and a vigorous exercise group (30 minutes of vigorous exercise). The researchers collected induced sputum and blood samples at baseline and 4 hours after the intervention to compare changes in airway and systemic inflammation. 

The study found that moderate exercise led to a significant reduction in the sputum eosinophil count and sputum percentage eosinophils compared to the control group. However, vigorous exercise had no effect on airway inflammation.

Interestingly, the anti-inflammatory effects of moderate exercise were greatest in participants with eosinophilic asthma, a type of asthma characterized by increased levels of eosinophils (a type of white blood cell). These participants experienced larger reductions in sputum eosinophils and larger increases in plasma interleukin (IL)-1ra (an anti-inflammatory cytokine) than participants with non-eosinophilic asthma.

On the other hand, vigorous exercise induced a systemic proinflammatory response in participants with eosinophilic asthma, as indicated by an increase in serum IL-5 and IL-1β. However, this increase had no effect on airway inflammation.

The study concluded that exercise intensity modifies the acute inflammatory response to exercise in adults with asthma. While a bout of moderate exercise can reduce eosinophilic airway inflammation, vigorous exercise does not have an effect on airway inflammation. Additionally, the effects of moderate exercise vary by asthma phenotype, with greater anti-inflammatory effects seen in participants with eosinophilic asthma.

Conclusion

So, what does this mean for people with asthma who want to exercise? It suggests that moderate exercise can be beneficial for reducing inflammation in the airways, but it's important to consider your asthma phenotype and exercise intensity. Vigorous exercise may not be the best choice for people with eosinophilic asthma, as it can lead to a systemic proinflammatory response.

It's important to note that this study only looked at acute changes in inflammation after a single bout of exercise. Future studies should examine the impact of exercise training at different intensities on inflammation and clinical asthma outcomes. But for now, it's clear that moderate exercise can have anti-inflammatory effects in people with asthma.