The negative impact of screens on sleep does not primarily stem from exposure to light (blue or otherwise), but rather from the phenomenon of procrastination that delays bedtime.

noli's read

Andy Galpin raises an interesting point that shifts the debate from biology to behavior. Research does indeed confirm that 'revenge bedtime procrastination' is a major factor in sleep deprivation, as highlighted by an observational study published in *Frontiers in Psychology* (2021). However, stating that light has 'almost nothing to do' with the problem is a simplification that ignores well-established mechanisms. Meta-analyses and randomized controlled trials (RCTs), such as those published in *The Journal of Clinical Endocrinology & Metabolism*, clearly demonstrate that blue light inhibits melatonin and shifts the circadian rhythm, which makes falling asleep biologically more difficult. While procrastination is an undeniable behavioral driver, the physiological effect of light remains a real obstacle to sleep quality. It is therefore more accurate to view these two factors as partners in sleep disruption rather than as mutually exclusive elements.

the sources

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3. 3Brown TM et al. 2022
4. 4Singh S et al. 2023
5. 5Kroese FM, De Ridder DTD, Evers C, Adriaanse MA. 2014