Mediating effect of physical activity on sleep and fatigue in haematological cancer patients

Purpose: Haematological cancer patients (HCP) usually report reduced physical activity (PA) and increased sleep deficiency. Sleep deficiency and PA's emerging and beneficial roles are intensely studied in solid cancer patients. However, there has been less attention to these issues in HCP. HCP's sleep deficiency is usually described as one of the five symptoms affecting these patients, and it is linked to higher levels of cancer-related fatigue (C-RF). C-RF also prevent HCP from being physically active. Indeed, C-RF and PA act in a vicious circle in these subjects, and the reduced PA could negatively interact with the side effect of the disease and its treatment. Moreover, most of the studies are focused on patients' conditions during or after chemotherapy. The present study assesses the differences in sleep by comparing PA and fatigue among HCP at the onset of chemotherapy. Furthermore, it investigates the relationship between sleep, PA and fatigue. Methods: The sample consisted of 58 newly diagnosed HCP (47.1 ± 15.4 yrs; 51.7% males). Participants filled in five questionnaires within two weeks from starting treatment: PSQI, a visual analogue scale, MFI-20, HADS, and EORTC QLQ-C30 to assess sleep, PA, fatigue, anxiety, depression, and quality-of-life, respectively. ANCOVA analysis investigated the differences between good and bad sleepers, while Mediation analysis described the relation between sleep, PA and fatigue. SPSS software was used to run the analysis. Results: HCP reported more sleep problems than the German population norm even at the chemotherapy onset. The HCP classified as good sleepers were less represented than those classified as bad sleepers (25% and 75%, respectively) and showed less frequent PA (p = .04), higher fatigue (p = .032), anxiety (p = .003), depression (p = .011) and pain (p = .011). The mediation analysis disclosed PA as a mediating factor between sleep and fatigue; in other words, it revealed significant indirect effects of sleep on fatigue through PA. Conclusions: Haematological cancer patients are described as predominantly sleep impaired even at the onset of chemotherapy. Bad sleep quality is associated with less frequent PA and higher fatigue. In addition, it highlights the combined action of sleep and PA on fatigue: an increment in PA frequency could be beneficial for fatigue improvements. PA and sleep could represent meaningful intervention targets to improve a patient's status before and at the onset of chemotherapy.