A randomized-controlled-trial of passive heating or cooling to improve sleep and facilitate weight loss in overweight/obese individuals.

INTERVENTION: In this randomized controlled trial (RCT), we will evaluate the effects of instructing overweight/ obese individuals to take a hot or cold bath/shower (whichever is preferred) about 90‐minutes prior to the time they wish to go to sleep, to determine whether this is effective in: (a) improving their sleep quality and increasing sleep times, and (b) as a consequence of going to bed earlier and sleeping a longer time, eat substantially less at night and therefore reduce their weight over time, relative to the control group participants. Based on the empirical studies where participants took a hot bath/shower as a modality of passive body heating (Allehe et al. 2013; Cynthia, 1996), the water temperature was 41‐42 degrees Celsius. In our study, we will advise the participants who are taking a hot bath/shower to make it as hot as they feel comfortable with, which should be around this water temperature. However, it is important not to give too detailed instructions that are disparate in extent to the participants who instead seek to take a cold bath/show. The participants will also be asked to complete the study questionnaire prior to being randomized to a study group, then they will participate in their group’s activities for 3‐months (i.e. reviewing and enacting the sleep hygiene information), and then completing the follow‐up questionnaire. Finally, the intervention condition will involve the participants either taking a hot/cold bath or shower every night for 3‐months, whichever is preferred), and completing the baseline and follow‐up questionnaires. Several strategies will be used to ensure that the study participants do adhere to the instructions they received. First, we will instruct them to complete the diary as accurately as they can and remind them that we are not testing them, but rather the effectiveness of a potential new weight loss program. Third, we will telephone all participants (including the control group participants) after 1‐week and 1‐month to check on their engagement in their group activities, and to remind them to complete the questionnaire at the end of the study. CONDITION: Obesity PRIMARY OUTCOME: Quality of sleep assessed using the Pittsburgh Sleep Quality Index (PSQI) Weight loss. ; This outcome will be assessed using digital weighing scale. SECONDARY OUTCOME: Binge‐eating assessed using the Binge‐Eating Scale (BES). ; ; Night eating assessed using the Night Eating Questionnaire (NEQ). ; Physical activity levels assessed using physical activity diary and the Global Physical Activity Questionnaire v2.0 INCLUSION CRITERIA: Criteria for Inclusion Study inclusion criteria are as follows: (i) participants are required to be overweight or obese; (ii) over 18 years and less than 66 years of age, and (iii) able to bathe themselves or have a regular carer who can arrange this for them.