Effects of incentive spirometer training on dyspnea and functional status in patients with long COVID

Since the emergence of Coronavirus Disease 2019 (COVID-19), it has become a global pandemic, profoundly affecting public health and daily life. Many recovering individuals report persistent or recurrent symptoms-fatigue, palpitations, cognitive impairment, shortness of breath, anxiety, and chest discomfort. These lingering effects impair work, daily function, and social interaction, placing a significant burden on individual quality of life and society.

This study aims to evaluate the effectiveness of using an induced Incentive Spirometer as a respiratory training tool to relieve long COVID symptoms.

This study, conducted from July 1, 2023, to May 11, 2024, at a regional teaching hospital in northern Taiwan, involved participants who had recovered from COVID-19 within the past year and had at least one long COVID respiratory symptom. Participants were assigned to one waiting control group and four experimental groups based on recovery time: within 3 months (Experimental Group 1), 3-6 months (Experimental Group 2), 6-9 months (Experimental Group 3), and 9-12 months (Experimental Group 4). The waiting control group received no interventions, while the experimental groups underwent inspiratory training using an induced Incentive Spirometer three times a week for 6 weeks (30 repetitions per session). Assessments were conducted before and after the intervention. Primary outcomes were the Dyspnoea-12 scale and Post-COVID-19 Functional Status scale. Secondary outcomes included the 6-minute walk distance and CaO₂.

Ninety participants were enrolled, with five withdrawing, leaving 85 for final analysis. After 6 weeks of intervention, the waiting control group showed no significant changes in dyspnea (p = 0.463) or post-COVID-19 functional status (p = 0.343). In contrast, all experimental groups showed significant improvements. Dyspnoea-12 scale scores improved in Experimental Groups 1 (p < 0.001), 2 (p = 0.008), 3 (p = 0.011), and 4 (p = 0.001). The Post-COVID-19 Functional Status scale also showed improvements in all Experimental Groups (Group 1: p < 0.001, Group 2: p = 0.003, Group 3: p = 0.002, and Group 4: p = 0.011). Significant improvements in 6-min walk distance were observed in some experimental groups, improvements were seen in Experimental Groups 1 (p < 0.001), 2 (p = 0.027), 3 (p = 0.68), and 4 (p = 0.172). No significant changes in CaO2 were observed (pre-test, p = 0.872 and post-test, p = 0.585).

Respiratory training using an induced Incentive Spirometer may help alleviate dyspnea and improve post-COVID-19 functional status in individuals with Long COVID. Earlier intervention appeared to yield better outcomes, although improvements were also observed even 9-12 months after infection. However, further studies with comprehensive pulmonary assessments are needed to confirm these findings.

NCT06165835, registered on 9 December 2023.