Figure 1.

Relative mitochondrial DNA copy number measured on blood samples collected on the 1^st day and 4^th day of the work week. The graphs show the changes of individuals' MtDNA levels (blue lines) and the mean change (bolded red line) between the 1^st and 4^th day (panel A); and the individual values of MtDNA (blue dot) and the corresponding means (central crossed bar) and standard deviations (shoulder dotted bar) for day 1^st and 4^th (panel B).