It seems plausible that sedentary people have more benefit on their sleep after joining an exercise event than active people do.27 The participants of our study had a normal PA level at baseline. Therefore, it can be assumed that PA of longer duration, above the national recommendations, is needed for this activity level to improve in sleep quality, but also the higher general activity during the day reveals sleep-promoting effects. Furthermore,

the Baecke sport index from baseline did not correspond to improvements in sleep quality and therefore the program seems to be effective for both unfit and fit participants. In general, the regression analysis did not show any correspondence to the intensity of PA. Even though, the recommendations to the participants to be physically active on a moderate intensity level, there was a range from PLX-4720 order 7 to 17 in individual data of perceived exertion on the Borg scale. The previous research is ambiguous about whether the dose–response effect is due to increased doses of exercise intensity, duration, or both.17 At least from our analysis we can conclude that the intensity might be of less importance than the duration

of PA. Buman and King17 learn more suggested that a minimum of 16 weeks of intervention would be needed along with exercise doses that meet or exceed current PA recommendations to answer this question satisfactorily. In our study with an intervention time of 6 weeks we achieved an average 3.1 point reduction in the PSQI global score16 which is comparable to the findings of King et al.28 Thiamine-diphosphate kinase with an average reduction of 3.3 after a 16-week

moderate endurance exercise intervention. As Youngstedt8 mentioned, an important, but overlooked, consideration in assessing treatment efficacy may be ceiling and floor effects, which dictate that the greater the initial impairment in sleep, the greater the potential for improvement. In the regression analyses severity of sleep symptoms at baseline (PSQI and SF-B) are one of the predictors for the changes in sleep quality. Therefore, it can be assumed that the higher the sleep severity symptoms the more steps and exercise of longer duration has to be done to get improvements in sleep. With respect to PA-F, PA-D, and PA-I but also the length of the treatment, additional research is needed in this area to formally test dose–response effects for chronic exercise on sleep. The second aim of the study was to display the week-to-week variability of sleep quality and PA starting from a baseline week over the 6-week intervention period. Our data showed as expected an increase of PA due to the intervention program: PA-F increased from 2.6 times in the baseline week to an average of 4.2 times during the weeks of intervention, PA-D augmented from 176 min in the baseline week to 279 min during the weeks of intervention. In contrast, PA-I showed a slight but statistically not significant increase from 11.9 to 12.3 over time.