[1] Norwegian Univ Sci & Technol, Dept Circulat & Med Imaging, K G Jebsen Ctr Exercise Med, N-7034 Trondheim, Norway
[2] St Olavs Hosp, Lung Dept, Trondheim, Norway
[3] Nord Trondelag Hlth Trust, Levanger Hosp, Levanger, Norway
[4] Trondheim Pulm Ctr, Trondheim, Norway
[5] Norwegian Univ Sci & Technol, Ctr Sports & Phys Activ Res, N-7034 Trondheim, Norway