“…Several quantitative studies explored the causality of fatigue, its relationship with disease activity, its impact on function and mental health (Brophy and Calin, ; Calin et al, ; Da Costa et al, ; Jones et al, ; van Tubergen et al, ), seasonal variations (Jones et al, ; Mengshoel, ; van Tubergen et al, ) and diurnal patterns (Jones et al, ). Studies have also focused on the impact of fatigue on quality of life (Mengshoel, ; Ward, ) and work (Barlow et al, ). Fatigue is as an obstacle to exercise (Sundström et al, ), and this can inhibit management programmes.…”