Light Therapy for Cancer Patients Undertaking Chemotherapy

Participants randomly allocated to the intervention group (as opposed to comparator group) will receive four weeks of green-blue light therapy plus sleep health guidelines while undertaking chemotherapy. Green-Blue Light Therapy: Green-blue light therapy will be delivered using wearable light therapy glasses (Re-Timer) for the duration of the intervention (four weeks). Participants will wear the light therapy glasses in their own home immediately upon waking in the morning for 30 minutes continuously at 500nm (max= 500nm, 230 µW/cm2, 506 lux), which is the highest setting on the glasses. Participants will be instructed by the study investigators on how to use the Re-Timer glasses according to manufacturer recommendations and will need to demonstrate appropriate use of the glasses. In cases where participants use prescription glasses, they will be asked to wear the light therapy glasses over the top. Written instructions will be provided as a reference for participants. For the initial three mornings of the intervention, participants will receive a phone call or email asking to provide feedback on any negative effects experienced while wearing the light therapy glasses. Participants will then be instructed to report any negative effects as required throughout the study period. Sleep Health Guidelines: Sleep health guidelines will be provided to the participants to take home and will be available to refer to at the commencement of the intervention period and the remainder of the study period. Sleep health guidelines will consist of evidence-based recommendations targeting improved sleep health. Recommendations will be adapted from resources provided by the National Sleep Foundation, Sleep Health Foundation and Buysse (2014). These guidelines will focus on recommendations promoting improved sleep health, including the implementation of night-time and daily routines, as well as recommendations regarding sleep environment. Research staff will deliver the sleep hygiene guidelines to study participants either in person at the participants treating centre or via Microsoft Teams. An individualised sleep report based off each study participants baseline findings will be used to personalise the sleep health guidelines to each participant. This will ensure that participants follow the sleep health recommendations that are most pertinent to the individual's unique behaviours and environment. Adherence to the intervention will be recorded using an intervention diary.