Blue light glasses can manipulate (i.e., inhibite) body melatonine production to re-adjust the circadian rhythm of shift workers, thereby having the potential to enhance viglance, cognitive function, and positive mood during night shift work.
Brief title
Health condition
Not applicable
Sponsors and support
Intervention
Outcome measures
Primary outcome
The primary outcome measure of the current study is need for recovery, as measured with the 11-item Need for Recovery Scale from the Dutch Questionnaire on the Experience and Evaluation of Work (Van Veldhoven, & Broersen, 2003). Higher scores indicate an increased need for recovery.
Secondary outcome
Secondary outcome measures include fatigue, motivation, concentration, and physical activity, measured with the Checklist Individual Strength (Beurskens et al., 2000). A higher compound score refer to an increase in fatigue, and a decrease in motivation, concentration, and physical activity. Furthermore, indications of stress and (lack of) physiological recovery are measured using the parameters Stress Level and Body Battery from the Garmin Vivo Smart 4 fitness tracker (Firstbeat, 2019). These parameters are derived from a combination of heart rate, heart rate variability, respiratory rate, and duration and intensity of body movements. As a covariate, chronotype is measured using one item of the reduced Morningness–Eveningness Questionnaire (Adan & Almirall, 1991).
Background summary
In this study, the effectiveness of blue light glasses in night shifts of security guards from the Netherlands Armed Forces Security Agency is evaluated. A randomised controlled cross-over trial is performed, with half of the study population using light glasses in a 5-week work shift schedule (comprising approx. 7 night shifts), and half of the study population using the light glasses during the following 5-week block schedule. Primary outcome is the need for recovery (validated quesionnaire); secondary outcome measures include fatigue, motivation, concentration, and physical activity (validated quesionnaire), as well as indications of stress and lack of physiological recovery as measured with a fitness tracker. The trial will be performed in the first half of 2021.
Study objective
Blue light glasses can manipulate (i.e., inhibite) body melatonine production to re-adjust the circadian rhythm of shift workers, thereby having the potential to enhance viglance, cognitive function, and positive mood during night shift work.
Study design
Baseline, week 5 (after 1st shift work block schedule), and week 10 (after 2nd shift work block schedule)
Intervention
Wearing blue light glasses for 30 minutes in the first half of a night shift
Inclusion criteria
Healthy volunteers from the Netherlands Armed Forces Security Agency aged 18 to 67 years.
Exclusion criteria
Individuals with diseases of the retina (e.g., macular degeneration) were excluded from the study, as were security guards who were not capable of fulfilling their duty tasks without wearing their own glasses.
Design
Recruitment
IPD sharing statement
Plan description
(Historical) registrations known in this register
In other registers
| Register | ID |
|---|---|
| NTR-new | NL9458 |
| CCMO | NL76088.028.20 / P2059 |