Other study outcomes
Activity: An actigraph is used to assess the participant’s level of physical activity. The actigraph is worn around the wrist for 14 consecutive days and nights for a reliable estimate of daily activity for 12 full days. The actigraph has been shown to be a reliable and valid instrument for the assessment of physical activity [53, 67].
Sleep parameters: During the 14 days participants wear the actigraph, a sleep diary [68] is also completed daily, if possible within one hour of getting out of bed in the morning. Participants have to fill in (1) the time they go to bed (in hours and minutes), (2) the time they try to fall asleep, (3) the sleep onset latency, (4) time awake at night, (5) time out of bed, (6) time of waking-up, (7) time of getting out of bed and (8) a rating of the sleep quality (scale 0–10) [
69]. Sleep problems are also assessed by the ISI [48] and the subscale sleep-rest of the Sickness Impact Profile (SIP) [70,
71].