Lung Transplantation Minimally Impacts Daily Physical Activity Post-Transplantation
J.R.Walsh, D.C.Chambers,S.T.Yerkovich, P.M.Hopkins and N.R.Morris2
Purpose: While physical activity level (PAL) is an important functional measure in people with chronic respiratory disease, little is known about PAL post lung transplantation (LTx). Aim: To compare PAL pre- and post-LTx and determine the relationship between changes in PAL and demographic (age), lung function (FEV1%) and exercise capacity measures.
Methods: Using a prospective observational design, participants were assessed pre- and 12 months post-LTx. PAL was defined as total energy expenditure in twenty-four hours/basal metabolic rate. PAL, mean minutes/day being physically active (1.69 metabolic equivalents (METs) or greater), and mean minutes/day performing moderate activity (3.0 METs or greater) were measured using the SenseWear multi-sensor device. Age, FEV1%, six-minute walk distance (6MWD), and quadriceps strength corrected for body weight (QS%) were assessed.
Results: 67 participants (40 males; 29 COPD, 15 idiopathic pulmonary fibrosis, 12 cystic fibrosis, 11 other), mean (SD) age 50.7 ± 12.4 years were included. Mean FEV1% increased by 52.6 ± 32.1% (p=0.001) and 6MWD increased by 174 ± 128m (p=0.001) 12 months after transplant, but QS% did not improve (-2.0 ± 21.0%, p=0.437). Mean PAL at 12 months (1.49 ± 0.23) had significantly improved compared to pre-LTx (1.40 ± 0.29, p=0.028). However, 17 (25.4%) participants remained extremely inactive (PAL below 1.4) and 37 (55.2%) participants were sedentary (PAL 1.4 to 1.69). Mean time physically active increased by 32 ± 130 minutes/day (p=0.045) but time performing moderate activity remained unchanged (p=0.062). Post-LTx, PAL was correlated with 6MWD (r=0.58, p=0.001), QS% (r=0.47, p=0.001) and age (r=-0.24, p=0.050) but not FEV1% (p=0.575). ∆PAL was correlated with ∆6MWD (r=0.37, p=0.002) but not with ∆QS% (p=0.090), age (p=0.716), or ∆FEV1% (p=0.875).
Conclusion: Most recipients remain physically inactive 12 months after lung transplantation despite significant improvements in lung function and exercise capacity. Age, exercise capacity and quadriceps strength appear important determinants of post-transplant PAL. However, there were only modest increases in physical activity post-transplantation.