For millions of people, the glow of the television is the last light they see before sleep. It feels harmless, even comforting. A ritual at the end of the day.

Yet beneath that glow lies a more complex story. The same light that helps us see our favourite shows may also be quietly undermining our recovery, disrupting circadian rhythms, and shifting the very hormones that govern sleep [1–5].

This isn’t about demonising screens or suggesting everyone abandon their evening rituals. It’s about understanding the science, and learning how to manage it intelligently.

The Biology of Blue Light

Light is the most powerful cue for our internal clock. Blue light, particularly in the 460–480 nanometre range, strongly influences circadian rhythms by interacting with intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells communicate directly with the brain’s master clock and regulate melatonin, the hormone that signals the body it is time to sleep [1,2].

Evening exposure delays melatonin release, pushes back sleep onset, and alters the architecture of sleep itself, reducing both slow-wave sleep (deep, restorative stages) and REM sleep (critical for learning and memory) [3–5].

Phones and tablets are particularly disruptive because of their proximity to the eyes. But large televisions, especially bright LED and QLED models in dark rooms, can still produce enough lux to suppress melatonin [2].

Television and Sleep: More Than Just Light

The science shows that televisions are not just sources of blue light — they’re also behavioural cues that shape arousal.

• Brightness and distance matter. A 55” OLED at 200 nits can expose the eyes to ~10 lux at two metres,  similar to a streetlight through a window. A 65” QLED at 350 nits can deliver ~18 lux, comparable to sitting under a kitchen lamp. Sitting further away and dimming brightness significantly reduces impact [6].

• Content matters. Thrillers, breaking news, or action films activate the sympathetic nervous system, elevate cortisol, and make it harder to transition into rest. Familiar comedies, nature shows, or lighter content can lower stress and promote laughter, easing the shift into a parasympathetic state [7,8].

• Timing matters. The hour before bed is when melatonin naturally rises. Studies consistently link late-night TV to delayed sleep onset, shorter duration, and reduced recovery,  particularly in children and adolescents [9–12].

The Case for Blue Light-Blocking Glasses

This is where targeted strategies can help. Research has shown that wearing blue light-blocking glasses in the evening can advance melatonin onset, improve sleep quality, and reduce the negative impact of screens [13–16].

Randomised trials demonstrate benefits not only for sleep disorders such as delayed sleep phase syndrome but also for mood and recovery in populations ranging from students to individuals with bipolar disorder [14,15,17].

Yet, results vary. Some individuals experience only modest improvements, suggesting that glasses work best when paired with broader evening light-management strategies [18–20].

Building Better Evening Routines

The evidence points to practical boundaries rather than total abstinence.

• Finish TV at least one hour before bed to protect the natural rise of melatonin [9–12].

• Choose calming, familiar content that lowers rather than raises arousal [7,8].

• Control brightness and distance - dim screens, activate night-mode settings, and sit further away [6].

• Keep ambient lights on - dim, warm lamps reduce contrast and blunt circadian disruption [2].

• Add recovery rituals such as reading, stretching, or meditation to reinforce wind-down.

For those who still need or want to use screens in the evening, combining these practices with blue light-blocking glasses provides an extra layer of protection [13–16].

Integrating Performance Protocols

This is where performance systems like HMN24 come into play. Technology, behaviour, and biology must be managed together.

• PRE-SLEEP: Designed to reinforce the body’s natural transition to rest, with magnesium glycinate, phosphatidylserine, and L-theanine to lower arousal, support melatonin pathways, and preserve sleep architecture.

• RISE: Supports circadian activation in the morning, countering the sluggishness that often follows disrupted nights.

• FLOW: Helps sustain dopamine balance and focus during the day, ensuring sharper cognition and reduced mental fatigue.

• Travel Pack: Integrates hydration, energy, and circadian tools for irregular schedules, from long-haul flights to night-shift rotations.

These aren’t replacements for boundaries, but complements. 

Television can be both a friend and a foe to sleep. Left unmanaged, it delays melatonin, fragments recovery, and disrupts circadian rhythm. Managed intelligently,  with calming content, dimmed settings, light-blocking tools, and supporting routines,  it can become part of a healthy evening ritual.

The key is not abstinence but awareness. Aligning biology with behaviour unlocks better sleep, recovery, and performance.

References

1. Silva-dos-Santos, A. (2016). Commentary on ‘blue-blocking glasses as additive treatment for mania: A randomized placebo-controlled trial’. Bipolar Disorders, 18(8), 708–709. https://doi.org/10.1111/bdi.12458

2. Gringras, P., Middleton, B., Skene, D. J., & Revell, V. L. (2015). Bigger, brighter, bluer-better? Current light-emitting devices – adverse sleep properties and preventative strategies. Frontiers in Public Health, 3, 233. https://doi.org/10.3389/fpubh.2015.00233

3. Pilorz, V., Tam, S. K. E., Hughes, S., Pothecary, C. A., Jagannath, A., Hankins, M. W., … & Peirson, S. N. (2016). Melanopsin regulates both sleep-promoting and arousal-promoting responses to light. PLOS Biology, 14(6), e1002482. https://doi.org/10.1371/journal.pbio.1002482

4. Chow, C., Ekanayake, K., & Hackett, D. (2024). Efficacy of morning shorter wavelength lighting in the visible (blue) range and broad-spectrum or blue-enriched bright white light in regulating sleep, mood, and fatigue in traumatic brain injury: A systematic review. Clocks & Sleep, 6(2), 255–266. https://doi.org/10.3390/clockssleep6020018

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6. Domagalik, A., Ogińska, H., Beldzik, E., Fa̧frowicz, M., Pokrywka, M., Chaniecki, P., … & Marek, T. (2020). Long-term reduction of short-wavelength light affects sustained attention and visuospatial working memory with no evidence for a change in circadian rhythmicity. Frontiers in Neuroscience, 14. https://doi.org/10.3389/fnins.2020.00654

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11. Wagnild, J., & Pollard, T. M. (2021). How is television time linked to cardiometabolic health in adults? A critical systematic review of the evidence for an effect of watching television on eating, movement, affect and sleep. BMJ Open, 11(5), e040739. https://doi.org/10.1136/bmjopen-2020-040739

12. Li, X., Buxton, O. M., Lee, S., Chang, A.-M., Berger, L. M., & Hale, L. (2019). Sleep mediates the association between adolescent screen time and depressive symptoms. Sleep Medicine, 57, 51–60. https://doi.org/10.1016/j.sleep.2019.01.029

13. Sasseville, A., Paquet, N., Sévigny, J., & Hébert, M. (2006). Blue blocker glasses impede the capacity of bright light to suppress melatonin production. Journal of Pineal Research, 41(1), 73–78. https://doi.org/10.1111/j.1600-079x.2006.00332.x

14. Esaki, Y., Kitajima, T., Ito, Y., Koike, S., Nakao, Y., Tsuchiya, A., … & Iwata, N. (2016). Wearing blue light-blocking glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: An open-label trial. Chronobiology International, 33(8), 1037–1044. https://doi.org/10.1080/07420528.2016.1194289

15. Esaki, Y., Takeuchi, I., Tsuboi, S., Fujita, K., Iwata, N., & Kitajima, T. (2020). A double-blind, randomized, placebo-controlled trial of adjunctive blue-blocking glasses for the treatment of sleep and circadian rhythm in patients with bipolar disorder. Bipolar Disorders, 22(7), 739–748. https://doi.org/10.1111/bdi.12912

16. Zerbini, G., Kantermann, T., & Merrow, M. (2018). Strategies to decrease social jetlag: Reducing evening blue light advances sleep and melatonin. European Journal of Neuroscience, 51(12), 2355–2366. https://doi.org/10.1111/ejn.14293

17. Ostrin, L., Abbott, K., & Queener, H. (2017). Attenuation of short wavelengths alters sleep and the ipRGC pupil response. Ophthalmic and Physiological Optics, 37(4), 440–450. https://doi.org/10.1111/opo.12385

18. Lee, J., & Cho, A. (2023). Blue light blocking glasses: Do they do what they promise? Journal of Emerging Investigators. https://doi.org/10.59720/23-028

19. Wirz-Justice, A., & Terman, M. (2016). Commentary on “blue-blocking glasses as additive treatment for mania: A randomized placebo-controlled trial”. Bipolar Disorders, 18(4), 383–384. https://doi.org/10.1111/bdi.12392

20. Silvani, M., Werder, R., & Perret, C. (2022). The influence of blue light on sleep, performance and wellbeing in young adults: A systematic review. Frontiers in Physiology, 13, 943108. https://doi.org/10.3389/fphys.2022.943108