OBJECTIVE
The usage of gadgets such as mobile phones, tablets, and/or laptops are associated with melatonin suppression and consequently a disturbance in sleep (e.g. delayed sleep). In order to reduce short-wavelength light emissions, gadget manufacturers have now developed apps that reduce these emissions of the display in an attempt to reduce the effects on sleep and circadian health. As a result, the goal of this study was to test the efficacy of the “Night Shift” app (see App link below) on melatonin responses.
WHAT THEY DID
Twelve participants were exposed to 4 different conditions: 1) a dim light control [orange goggles]; 2) a high-circadian stimulus true positive [blue light goggles] intervention; 3) a low-correlated colour temperature “Night Shift” intervention from the device (iPad, Apple Inc.); and 4) a high-correlated colour temperature “Night Shift” light from the device (iPad, Apple Inc.). The two iPad lighting interventions were generated by adjusting the color temperature of the “Night Shift” application to one of the two extremes of the app (i.e. the warmer or less-warm option).
WHAT THEY FOUND
Melatonin suppression was significantly greater after two hours of exposure compared to just one hour. Furthermore, over the 2-hour exposure, melatonin suppression from exposure to the blue light goggles intervention was significantly higher in comparison to the two “Night Shift” interventions. Nevertheless, melatonin suppression between the two “Night Shifts” (both high- and low-correlated color temperature) was not different.
Practical Takeaways
The results from this study demonstrate that the three interventions resulted in melatonin suppression. Interestingly, while the blue light googles resulted in an increase of melatonin suppression during the first and second hour, the “Night Shift” interventions only increased melatonin suppression during the first hour. These findings demonstrate that the “Night Shift” interventions were effective for decreasing the harmful effect of the devices from the first to the second hour.
Importantly, the melatonin suppression observed did not differ between the two “Night Shift” interventions. As a result, athletes are advised to adjust both the display’s spectral composition and the display brightness when using the devices in the evening (i.e. when it’s dark).
