Night Shift Work

The primary aim of this study is to investigate the effects of reducing weekly working hours among employees working night shifts regularly from 38 hours 15 minutes to 36 hours on payroll-based, objective working-hour characteristics, sickness absence, and workforce retention. The secondary aim is to investigate experiences of promoting and hindering factors related to the working-hour reduction, its implementation process, and perceived benefits and challenges. The working-hour reduction will be implemented in three Finnish wellbeing services counties with different starting dates, the first being in late September 2026 and the latest in early 2027. The working-hour reduction has been agreed upon by the parties to the collective agreement for Finnish public social and health care. Thus, intervention is a so-called natural experiment in a real-life setting. The effects of the intervention will be evaluated using a quasi-experimental design with staggered, non-randomized implementation across participating counties. Administrative, payroll-based, employer-owned working-hour data, including records of sickness absences without any medical or health information and other absences (including unpaid, education, and childcare), will be used to compare changes before and during the intervention among work units participating in the working-hour reduction. The investigation will also utilize matched work units that do not participate in the reduction (i.e., intervention) as control units (i.e., continuing standard working-hour arrangements).

This study evaluates the effects of a Combined Lifestyle Intervention Program (CLIP) on sleep, lifestyle behaviors, obesity risk and health in night-shift workers. The primary objective is to assess the effect of the CLIP on objectively measured sleep duration. Secondary objectives include behavioral outcomes related to sleep, diet, physical activity, and stress, as well as body weight and metabolic outcomes, . It is hypothesized that CLIP participants will show a greater increase in sleep duration than controls, alongside favorable changes in lifestyle and health outcomes.

Observational study: The goal of this observational study is to learn about the association between slow wave activity before awakening and post-awakening psychomotor vigilance task in time-fixed, 2-hour, simulated night naps in healthy individuals. The main question aims to answer is: Is the quantity of slow wave activity immediately before awakening associated with post-awakening psychomotor vigilance task metrics when awakened after 2-hour nap at night?

In this randomized controlled trial, the investigators will assess the health impacts of optimizing the timing of dietary consumption in nurses and nursing assistants who work night shifts, have a habitual eating window of 14 hours or more, and elevated weight. Participants will be randomized to one of three groups: (1) dietary monitoring, (2) dietary monitoring plus 10-hour daytime time-restricted eating (TRE), or (3) TRE with a low-glycemic snack during night shifts. The study includes a 2-week screening/baseline health assessment, with follow-up health assessments at 3-, 6- (primary outcome), and 12 months.