The relationship between muscle strength and oxygenation and activities of daily living in adolescents and young adults with pulmonary arterial hypertension.

Pulmonary arterial hypertension leads to dyspnoea, fatigue, and oxygen desaturation, limiting activities of daily living and functional capacity. This study aimed to evaluate the impact of pulmonary arterial hypertension on activities of daily living performance, functional capacity, peripheral muscle strength, oxygen dynamics, and energy expenditure. Eighteen adolescents and young adults with pulmonary arterial hypertension (10 females, 8 males; age 9-30 years) and 15 healthy controls (10 males, 5 females; age 9-30 years) were included. Peripheral muscle strength was assessed using a handheld dynamometer, functional capacity via the 6-minute walk test, and muscle oxygenation through near-infrared spectroscopy. Lower-limb endurance was evaluated with the 1-minute sit-to-stand test and activities of daily living performance with the Glittre Activities of Daily Living test. Compared to controls, the pulmonary arterial hypertension group had significantly lower 6-minute walk test distance (441.9 m versus 636.9 m; p < 0.001), reduced sit-to-stand repetitions (28 versus 42.1; p < 0.001), weaker peripheral strength, and lower minimum muscle oxygen saturation (24.9% versus 51.8%; p < 0.001). Glittre Activities of Daily Living test duration was longer (143 s versus 105 s; p < 0.001), with greater oxygen desaturation (-13% versus -1%; p < 0.001), higher dyspnoea scores using modified Borg scale (5 versus 1; p < 0.001), and blunted heart rate response (ΔHR [change in heart rate]: 32 versus 64; p = 0.011). These findings demonstrate that pulmonary arterial hypertension significantly impairs both cardiopulmonary and peripheral muscle function. Protecting muscle health and improving functional capacity should be prioritised to enhance quality of life in this population.