Peripheral muscle strength and functional capacity in patients with moderate to severe asthma

Abstract

Background: The adequate control of asthma includes the absence of nocturnal symptoms, minimal use of medication, normal or nearly normal lung function and no limitations to physical activity. The choice of a more sedentary lifestyle can lead to physical de-conditioning, thereby aggravating asthma symptoms and increasing the risk of obesity. Methods: This study aimed at performing a battery of function-related assessments in patients with asthma and comparing them to a healthy control group. A prospective, transversal and case-control study was designed. It was set up at Santa Casa de Misericórdia Hospital-Sao Paulo and Nove de Julho University on a population of outpatients. Subjects of the study were patients affected by moderate to severe asthma. A case-control study was carried out involving 20 patients with moderate to severe asthma and 15 healthy individuals (control group). All participants underwent body composition analysis (BMI and BIA) and a controlled walk test (Shuttle test), resistance muscle test (1RM) and answered a physical activity questionnaire (IPAQ). The group with asthma also answered a questionnaire addressing the clinical control of the illness (ACQ). Results: In comparison to the control group (unpaired Student's t-test), the patients with asthma had a significantly higher BMI (31.09 ±5.98 vs. 26.68 ± 7.56 kg/m2) and percentage of body fat (38.40 ±6.75 vs. 33.28 ±8.23%) as well as significantly lower values regarding distance traveled on the walk test (369 ± 110 vs. 494 ± 85 meters) and metabolic equivalents (3.74 ± 0.87 vs. 4.72 ± 0.60). A strong correlation was found between the distance completed and peripheral muscle strength (r: 0.57, p < 0.05) and METs (Metabolic equivalents - minutes/week) and peripheral muscle strength of 1RM (r: 0.61, p = 0.009). Conclusions: The individuals with asthma had lower functional capacity and levels of physical activity as well as a higher percentage of body fat compared to healthy individuals. This suggests that such patients have a reduced physical performance stemming from a sedentary lifestyle. Despite the existence of few studies reporting moderate to severe asthmatic patients and functional capacity assessment, it is clear that the assessment presented in the current study is a valid and accessible tool in clinical practice.