Subgroups underwent either a single exposure of 1 h or repeated exposures three times weekly for 1 h during 3 weeks (3W), 5 weeks (5W), 5 weeks followed by 2 weeks without exposure (5W + 2) or 5 weeks followed by 4 weeks without exposure (5W + 4).
Subgroups underwent either a single exposure of 1 h or repeated exposures three times weekly for 1 h during 3 weeks (3W), 5weeks (5W), 5 weeks followed by 2 weeks without exposure (5W + 2) or 5 weeks followed by 4 weeks without exposure (5W + 4).