By Dr. Brandon Roberts | Reading Time: 16 minutes |

Adults spend about ⅓ of their life sleeping.^[1]Alger, SE., et al. (2015): The role of sleep in human declarative memory consolidation. In: Curr. Top Behav Neurosci. URL: https://www.researchgate.net/publication/265791872_The_Role_of_Sleep_in_Human_Declarative_Memory_Consolidation. Sleep is defined as a reversible state where someone is disengaged and unresponsive to the environment. Sleep is critical for recovery – maybe the most critical element. Athletes, whether elite or recreational, often have sleep disturbances due to competitions, training schedules, mental stress, social requirements, or disruption of their normal circadian rhythm.

Sleep latency data that athletes (including individual sports group data) compared with non-sports controls, including sleep latency in minutes, sleep duration (time asleep in hours:minutes) and sleep efficiency. The values are mean values + standard deviation. (Graphic Source: Leeder et al., 2012)

When athletes do sleep they can take longer to fall asleep (sleep latency) and have lower quality of sleep (sleep efficiency) than non-athletes.^[2]Leeder, J., et al. (2012): Sleep duration and quality in elite athletes measured using wristwatch actigraphy. In: J Sports Sci. URL: https://www.ncbi.nlm.nih.gov/pubmed/22329779.  There is also some evidence to suggest elevated core temperature – from training late at night – can disrupt sleep.^[3]Kräuchi, K. (2007): The thermophysiological cascade leading to sleep initiation in relation to phase of entrainment. In: Sleep Med Rev. URL: https://www.ncbi.nlm.nih.gov/pubmed/17764994. Furthermore, athletes who participate in solo sports rather than team sports tend to have more issues with sleep.^[4]Erlacher, D., et al. (2011): Sleep habits in German athletes before important competitions or games. In: J Sports Sci. URL: https://www.ncbi.nlm.nih.gov/pubmed/21506041.

Circadian patterns of body core temperature (CBT), heat production and heat loss according to Aschoff, 1983 in 8 women (22-26 years), recorded during the luteal phase at an ambient temperature of 281°C, naked, supine in bed). Note: CBT decreases when heat loss exceeds heat production. However, training in the evening can delay the temperature drop – and thus affect the time you fall asleep and the length of sleep. (Graphic Ssource: Kräuchi et al., 2007)

But first, let me give a brief reminder of why sleep is important for athletes:

• Physiologically, sleep debt (aka lack of sleep) is linked to reduced immune function^[5]Reilly, T. / Edwards, B. (2007): Altered sleep-wake cycles and physical performance in athletes. In: Physiol Behav. URL: https://www.ncbi.nlm.nih.gov/pubmed/17067642. even if it doesn’t have large effects on acute strength performance.^[6]Blumert, PA., et al. (2007): The acute effects of twenty-four hours of sleep loss on the performance of national-caliber male collegiate weightlifters. In: J Strength Cond Res. URL: https://www.ncbi.nlm.nih.gov/pubmed/18076267. Yet, longer term sleep deprivation can decrease performance in the bench press, leg press, and deadlift after the second night of sleep loss.^[7]Reilly, T. / Piercy, M. (1994): The effect of partial sleep deprivation on weight-lifting performance. In: Ergoom. URL: https://www.tandfonline.com/doi/abs/10.1080/00140139408963628.
• From a psychosocial perspective, sleep loss affects athletes mood and decision making skills. It has also been linked to underperformance / overtraining syndrome. The problem is that a lot of people sacrifice sleep for other activities, especially if they don’t know why sleep is important. This leads to a vicious cycle.

My goal in this article is to give you some things to change to help you sleep better in hopes of improving performance or general well-being. For this article we’ll focus on naps and blue light (BL). If you want more background information on how to determine if you have sleep issues please read my first sleep article here.

Sleep Interventions for Performance & Cognition                     

Naps

As a child you may have taken naps. I remember them fondly and still use them when I’m really struggling with recovery. Naps can be used to make up for sleep loss and alleviate accumulated sleep debt. However, research on the impact of napping on athletic performances is relatively small with only a handful of studies on naps in athletes:

Naps help alertness and sprint performance

Waterhouse et al., found naps after lunch improved alertness and performance with sleep loss.^[8]Waterhouse, J., et al. (2007): The role of a short post-lunch nap in improving cognitive, motor, and sprint performance in participants with partial sleep deprivation. In: J Sports Sci. URL: https://shapeamerica.tandfonline.com/doi/abs/10.1080/02640410701244983.

Sprint time during three sprints (Trial 1 – 3) with and without naps for a distance of 20 meters. Mmean values ±  standard deviations. (Graphic Sourceource: Adapted from Waterhouse et al., 2017)

Naps help cognition

Petit et al., found no differences in performance with a 20 minute post-meal nap independent of sleep loss.^[9]Petit, E., et al. (2014): A 20-min nap in athletes changes subsequent sleep architecture but does not alter physical performances after normal sleep or 5-h phase-advance conditions. In: Eur J Appl. Physiol. URL: https://www.ncbi.nlm.nih.gov/pubmed/24276580. However, more recently they have shown a 20 minute nap has a beneficial effect on cognitive processing in athletes.^[10]Petit, E., et al. (2018): Effects of a 20-min nap post normal and jet lag conditions on P300 components in athletes. In: Int J Sports Med. URL: https://www.ncbi.nlm.nih.gov/pubmed/29758571.

Naps help cognition and performance if there is sleep debt.

Daaloul et al., found improvements in alertness and cognitive performance with a 30 minute nap, but no performance benefits if there was no sleep debt. On the other hand, they did show an increase in performance for athletes who were sleep restricted.^[11]Daaloul, H. / Souissi, N. / Davenne, D. (2019): Effects of napping on alertness, cognitive, and physical outcomes of karate athletes. In: Med Sci Sports Exerc. URL: https://www.ncbi.nlm.nih.gov/pubmed/30239491.

Subjective alertness and fatigue with (Nap, 30 min. at 1 pm) and without nap (No Nap), after a reference night with sufficient sleep (RN) and partial sleep deprivation (PSD) in 13 karate athletes at international level. Average values ± standard deviation. (Graphic Source: Daaloul et al., 2019)

Time to exhaustion during a Karate-specific test (KST) with a 30-minute nap (□) at noon and no nap (○), after a reference night with sufficient sleep (RN) and partial sleep deprivation (PSD). ** = Significant difference to PSD without nap (P < 0.01); €€ = Significant difference to RN without nap (P<0.01). (Grahic Source: Daaloul et al., 2019)

Naps help performance estimation by coaches

O’Donnell et al., found that a nap of <20 minutes increases performance estimation from coaches and jump velocity during netball competition.^[12]O’Donnell, S. / Beaven, CM. / Driller, M. (2018): The influence of match-day napping in elite female netball athletes. In: Int. J. Sports Physiol. Perform. URL: https://www.researchgate.net/publication/323792047_The_Influence_of_Match-Day_Napping_in_Elite_Female_Netball_Athletes.

Naps help performance if sleep restricted

Hammouda et al., found a 20  or 90 minute nap, if sleep restricted, improved performance with the longer the nap duration the greater the improvement in performance.^[13]Hammouda, O., et al. (2017): Diurnal napping after partial sleep deprivation affected hematological and biochemical responses during repeated sprint. In: Biol Rhythm Res. URL: https://www.tandfonline.com/doi/abs/10.1080/09291016.2018.1429553.

Naps help endurance performance if you don’t get much sleep

Blanchfield et al., found improved endurance performance with a short afternoon nap in runners who had < 7h of sleep.^[14]Blanchfield, AW., et al. (2018): The influence of an afternoon nap on the endurance performance. In: Eur J Sport Sci. URL: https://www.tandfonline.com/doi/abs/10.1080/17461391.2018.1477180. Furthermore, the less sleep the better the change in performance.

Night sleep predicted the change in the time to exhaustion (TTE) after a short nap. The data are individual (dot plot). (Graphic Source: Adapted from Blanchfield et al., 2018)

Naps help recovery

Keramidas et al., demonstrated a 30-minute nap can alleviate the impairment in exercise endurance for military training.^[15]Keramidas, ME., et al. (2018): A brief pre-exercise nap may alleviate physical performance impairments induced by short-term sustained operations with partial sleep deprivation – A field-based study. In: Chronobiol Int. URL: https://www.tandfonline.com/doi/full/10.1080/07420528.2018.1490316.

These studies give us a good base of knowledge to say that naps are beneficial for athletes by improving performance, and cognitive function when in sleep debt. Furthermore, if we look at other factors like memory consolidation, learning,^[16]Heim, S., et al. (2017): A Nap But Not Rest or Activity Consolidates Language Learning. In: Front Psychol. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5432759/. and decision making we can see that naps help have multiple benefits.

How long should naps be then, if we know they have the potential to help?

Naps ranging from 10-20 minutes have been shown to improve alertness and performance after sleep restriction.^[17]Gillberg, M., et al. (1996): The effects of a short daytime nap after restricted night sleep. In: Sleep. URL: https://www.ncbi.nlm.nih.gov/pubmed/8899936.^[18]Tietzel, AJ. / Lack, LC. (2002): The recuperative value of brief and ultra-brief naps on alertness and cognitive performance. In: J Sleep Res. URL: https://www.ncbi.nlm.nih.gov/pubmed/12220317. Naps also show similar benefits without sleep restriction.^[19]Hayashi, M. / Ito, S. / Hori, T. (1999): The effects of a 20-min nap at noon on sleepiness, performance and EEG activity. In: Int J Psychophysiol. URL: https://www.ncbi.nlm.nih.gov/pubmed/10380949.

A common issue with naps is sleep inertia, which is the grogginess you feel when you wake up from a nap. I’m sure you’ve felt this or have seen someone else feel it. They’re fairly groggy or even grumpy when they wake up from a nap. A solution to this is to take shorter naps of ~10 minutes. Another solution is to take a full 90 minute nap to allow for a complete sleep cycle.^[20]Davies, DJ. / Graham, KS. / Chow, CM. (2010): The effect of prior endurance training on nap sleep patterns. In: Int J Sports Physiol Perform. URL: https://www.ncbi.nlm.nih.gov/pubmed/20308699. Indeed, naps present a practical strategy for recovery for athletes and are commonly identified as an area that athletes can improve.^[21]Venter, RE. (2014): Perceptions of team athletes on the importance of recovery modalities. In: Eur J Sports Sci. URL: https://www.ncbi.nlm.nih.gov/pubmed/24444246.

Change in subjective (left) and objective (right) alertness after 30-s, 90-s and 10-minute naps compared to no naps, indicated by the mean scores on the Stanford Sleepiness Scale (SSS) (1 = highest attention). (Graphic Source: Tietzel et al., 2002)

If we want to take a nap when should we do it?

Well, most people probably think of the afternoon – they would be correct. The post-lunch period seems to be ideal whereby a post-lunch alertness decrease can be partially explained by meal ingestion, but also reflects the harmony of your circadian rhythm.^[22]Monk, TH., et al. (2005): The Post-Lunch Dip in Performance. In: Clin Sport Med. URL: https://www.sportsmed.theclinics.com/article/S0278-5919(04)00138-3/abstract.

To summarize: naps are a great even if you aren’t sleep deprived. I recommend using them for all types of athletes, especially those who are sleep restricted or those who need help recovering. Short naps seem to work best (20-30 minutes) preferably in the post-lunch period.

Whether for mental or physical performance: A short nap (10-20 minutes), e.g. after lunch, can not only be refreshing for the soul, but also increase your performance. (Image Source: depositphotos /dontcut)

Blue Light Exposure

Blue light is all around us. It’s emitted from our smart devices, TVs, tablets and even energy efficient light bulbs. It has the ability to shift or reset the circadian rhythm (Khasla 2003).

It can also lower melatonin levels,^[23]Cajochen, C., et al. (2005): High sensitivity of human melatonin, alertness, thermoregulation, and heart rate to short wavelength light. In: J Clin Endocrinol Metab. URL: https://www.ncbi.nlm.nih.gov/pubmed/15585546. reduce sleepiness,^[24]Kaida, K., et al. (2006): Indoor exposure to natural bright light prevents afternoon sleepiness. In: Sleep. URL: https://www.ncbi.nlm.nih.gov/pubmed/16676779. and increase alertness.^[25]Sahin, L. / Figueiro, MG. (2013): Alerting effects of short-wavelength (blue) and long-wavelength (red) lights in the afternoon. In: Physiol Behav. URL: https://www.ncbi.nlm.nih.gov/pubmed/23535242. There does seem to be one possible benefit – it could increase – performance.^[26]Chellappa, SL., et al. (2011): Non-visual effects of light on melatonin, alertness and cognitive performance: can blue-enriched light keep us alert? In: PLoS One. URL: https://www.ncbi.nlm.nih.gov/pubmed/21298068.

Inhibition of melatonin release as a function of the circadian stimulus (CS). Horizontal arrows show the corresponding CS value at different corneal illumination levels from incandescent lamps (solid arrows) and daylight illumination (dashed arrows) for one-hour exposures. The shaded area represents the modelled ‘best fit’ (solid black line, r2 = 0.82) using a four-parameter logistic equation and the standard error of the best-fit coefficients to the model.  LUX = Unit of illuminance. (Graphic Source: Figueiro et al., 2006)

Ultimately, much like anything else in health and fitness there are pros and cons. The dose and timing seem to be key.

The Good

Light exposure can enhance alertness and performance,^[27]Vandewalle. G., et al. (2006): Superiority of blue (470 nm) light in eliciting non-image forming brain responses during auditory working memory in humans: a fMRI study. In: J Sleep Res. URL: https://www.researchgate.net/publication/295296944_Superiority_of_blue_470_nm_light_in_eliciting_non-image_forming_brain_responses_during_auditory_working_memory_in_humans_a_fMRI_study.^[28]Vandewalle. G., et al. (2006): Daytime Light Exposure Dynamically Enhances Brain Responses. In: Curr Biol. URL: URL: https://www.ncbi.nlm.nih.gov/pubmed/16920622. but not just any color. It has firmly been shown that exposure to blue light, when compared to green^[29]Vandewalle, G., et al. (2007): Wavelength-Dependent Modulation of Brain Responses to a Working Memory Task by Daytime Light Exposure. In: Cereb Cortex. URL: https://www.ncbi.nlm.nih.gov/pubmed/17404390. or violet,^[30]Vandewalle, G., et al. (2007): Brain responses to violet, blue, and green monochromatic light exposures in humans: prominent role of blue light and the brainstem. In: PLoS ONE. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2082413/?report=reader. is more effective in enhancing responses to a memory task. Blue light also has the potential to change circadian rhythms (which might be important for shift work and jet lag).^[31]Sack, R., et al. (2007): Circadian rhythm sleep disorders: part II, advanced sleep phase disorder, delayed sleep phase disorder, free-running disorder, and irregular sleep-wake rhythm. In: Sleep. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2082099/. For example, blue light exposure can decrease salivary melatonin and increase subjective ratings of cognitive performance.^[32]Chellappa, SL., et al. (2011): Non-Visual Effects of Light on Melatonin, Alertness and Cognitive Performance: Can Blue-Enriched Light Keep Us Alert? In: URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3027693/.

One elegant series of studies aimed to figure out if blue light can help exercise performance. Over the course of his PhD, Raphael Knaier discovered a number of novel things about how we can use blue light (BL) in athletes.

Dose-response relationship between light exposure and cycling performance

When you design experiments the best place to start is a dose-response study. This design gives you more opportunity to find what the best dose is so that you can use that going forward to take a more in-depth approach at answering a scientific question.

In 2006 this study found that a long duration of BL exposure consisting of 2 hours before exercise and during exercise can increase total work in a medium length cycling time-trial.^[33]Knaier, R. (2016): Dose-response relationship between light exposure and cycling performance. In: Scand J Med Sci Sports. URL: https://www.ncbi.nlm.nih.gov/pubmed/26271769.

Mean value (+ standard deviation) of work done (in kJ) after/under bright light (Bright Light) and after/under moderate light (Moderate Light) for each interval of four minutes in the groups 2HEX (120 minutes before and during exposure, n=16), 1HEX (60 minutes before and during exposure, n=10) or 1H (only 60 minutes before exposure. (Graphic Source: Knaier et al., 2015)

Furthermore, compared to participants in the control light group, the BL group performed significantly more work during the first 24 minutes of the time trial indicating relatively higher effects for shorter time trials. However, two hours of light exposure seems like a very long time and exposure to light during a competition is probably out of our control.

Moving on to the next question: can blue light help other types of performance that are more applicable or if given only pre-testing? Enter, another study in this series, but this time in elite athletes.

Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance

This study – used a more feasible model of blue light exposure of 60 minutes vs. a light control. They found that exposure to BL slightly improved maximal cycling performance (total work) in a 12 minute time trial.^[34]Knaier, R. (2017): Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance. In: Front Physiol. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5410597/pdf/fphys-08-00264.pdf. This data is further supported by a correlation between the amount of exposure to melanopic light and the performance gain during the time trial.

Correlation between the amount of exposure to non-imaging light (i.e. melanopic lx) and the “power gain” (in %) during the time trial, defined as the ratio of power in the first and last minute of the time trial (BRIGHT = bright light; BLUE = blue light; CONTROL = control light. (Graphic Source: Knaier et al., 2017)

What about in non-athletes? Does blue light matter? Can it help increase exercise intensity? Enter, the next study in the series.

Morning bright light exposure has no influence on self-chosen exercise intensity and mood in overweight individuals – A randomized controlled trial

It appears not. The study ultimately found that BL exposure prior and during exercise (at 08:30am) may not increase self-chosen exercise intensity or decrease subjective effort in a 30-min endurance exercise session.^[35]Knaier, R. (2018): Morning bright light exposure has no influence on self-chosen exercise intensity and mood in overweight individuals – A randomized controlled trial. In: Chronobiol Int. URL: https://www.ncbi.nlm.nih.gov/pubmed/29260907.

Power Output (A), Heart Rate (B), Perceived Effort Rating (C) and Power Output as a percentage of peak power from the cardiorespiratory fitness test (D) during the training session in each group. Bright = bright light (~4,400 lx); Control = control light (~230 lx). (Graphic Source: Knaier et al., 2017)

Mood evaluation of the participants (interquartile range), if not otherwise indicated. Bright light = bright light (~4,400 lx); control light = control light (~230 lx). (Graphic Source: Knaier et al., 2017)

Practically, this could be because of the intensity, type of exercise, or time of day.  although I wouldn’t expect this population to see a benefit since they were untrained. It’s possible only the upper level of athletes can benefit.

Lastly, can blue light help strength?

Effects of bright and blue light on acoustic reaction time and maximum handgrip strength in male athletes: a randomized controlled trial

It appears not, at least in handgrip strength, as this study found that 60 minutes of exposure to BL can reduce melatonin but did not improve reaction time or handgrip strength.^[36]Knaier, R. (2017): Effects of bright and blue light on acoustic reaction time and maximum handgrip strength in male athletes: a randomized controlled trial. In: Eur J Appl Physiol. URL: https://www.ncbi.nlm.nih.gov/pubmed/28597081.

Effects of different light exposures on grip strength. Bright light = Bright (n=24); blue light = Blue (n=24); control light = Control (n=24). (Graphic Source: Adapted from Knaier et al., 2017)

Taken together, we can see that BL exposure can help performance. This is likely to only make a difference in high level athletes if given directly before competition and only in medium length cycling competitions. If we combine this with the alertness / cognition data from the BL literature we can speculate athletes may want to use this method if they are competing in the evenings. However, more studies are needed to see if this can help the average powerlifter or physique athlete.

One of the first reason I wanted to incorporate this line of research is to show you how a series of studies (by one group) can really focus in on a topic. There will always be a need for more studies since each one leads to new questions. Another reason I wanted to include this literature is to fend off any future claims of “blue light (exposure) can improve performance” outside of the context of the studies above. Finally, the last reason was to demonstrate how something can be both good and bad in different contexts.

The Bad

Blue light isn’t all good. If it has the potential to improve performance then it probably has an affect on sleep too. Before we get too deep I think it would be beneficial to give a brief reminder of what melatonin does in the body.

Melatonin is important because it can be altered, especially by BL, which disrupts sleep. However, the use of electronic devices before sleep may disrupt sleep even if melatonin is not suppressed since what we do with these devices may be exciting itself – like watching an action or horror movie.

If we know that BL can be bad close to bedtime, what’s a simple fix?

The answer: blue light blocking glasses

You’ve probably heard of them or may even have a pair. Given the low cost of these glasses it seems that they could be an easy way to help mitigate the issues with blue light from electronic devices at night. Next, we’ll go through some research on why.

Blue light blocking glasses were recently shown to result in higher melatonin levels, improved sleep efficacy and latency compared to control glasses.^[37]Ayaki, M., et al. (2016): Protective effect of blue-light shield eyewear for adults against light pollution from self-luminous devices used at night. In: Chronobiol Int.URL: https://www.tandfonline.com/doi/abs/10.3109/07420528.2015.1119158.

Sleep quality indices and sleepiness measurements, including sleep efficiency (Sleep efficacy in %), time to fall asleep (Sleep latency in minutes), after use of control eyewear and blue-light shield eyewar. (Graphic Source: Ayaki et al., 2016)

In another study, blue light blocking glasses were deemed useful in adolescents by mitigating the negative effects modern lighting in the evening.^[38]van der Lely, S., et al. (2015): Blue Blocker Glasses as a Countermeasure for Alerting Effects of Evening Light-Emitting Diode Screen Exposure in Male Teenagers. In: J Adol Health. URL: https://www.sciencedirect.com/science/article/abs/pii/S1054139X14003243.

Melatonin profile (saliva concentration) of 12 male volunteers (mean values ± SEM). * = significant difference between blue light filter glasses (BB) and control glasses (CL) on. A tendency is represented by a white circle (○). The x-axis indicates the average time of day for sampling. (Graphic Source: van der Lely et al., 2015)

In a randomized trial, amber lenses were used to block blue light.^[39]Burkhart, K. / Phelps, JR. (2009): Amber lenses to block blue light and improve sleep: a randomized trial. In: Chronobiol Int. URL: https://www.ncbi.nlm.nih.gov/pubmed/20030543. The authors found significant improvements in sleep quality relative to the control group. Mood significantly improved relative to controls too.

I could only find one sleep in recreation athletes that used blue light glasses.^[40]Knufinke, M., et al. (2018): Restricting short-wavelength light in the evening to improve sleep in recreational athletes – A pilot study. In: Eur J Sport Sci. URL: https://www.tandfonline.com/doi/full/10.1080/17461391.2018.1544278. This study found that blocking short-wavelength light resulted in a faster time falling asleep, better subjective sleep quality and higher subjective alertness in the morning, compared to controls.

Effects of wearing blue light blocking glasses on sleep quality, the subjective feeling of being refreshed and the total sleep time (in hours) in 15 recreational athletes (12 women, 3 men) compared to the control situation (no blue light blocking glasses). (Graphic Source: Adapted from Knufinke et al., 2019)

On the other hand, a recent systematic review noted a lack of high quality evidence in studies using blue light glasses to improve visual performance and sleep quality^[41]Lawrenson, JG., et al. (2017): The effect of blue‐light blocking spectacle lenses on visual performance, macular health and the sleep‐wake cycle: a systematic review of the literature. In: Optal Physiol Optics. URL: https://onlinelibrary.wiley.com/doi/full/10.1111/opo.12406?casa_token=HU8Yg8IP-TAAAAAA%3AhKuDK2i8G-dbQv04GgoD_PqDTNv53u1KTEB-irLb7EAjmAPLlu9i1ZsYtWGXIVVnNhFp7m4Z7Dw. so more research is (always) needed. One interesting factoid I found was that blue light has larger effects on younger compared to older people.^[42]Daneault, V., et al. (2014): Aging Reduces the Stimulating Effect of Blue Light on Cognitive Brain Functions. In: Sleep. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3865352/.

Artificial light with a bright color spectrum can have a negative impact on sleep quality and efficiency (and thus regeneration) in the evening hours. Anyone sitting at a computer screen in the evening should therefore take measures to filter blue light to ensure a more optimal release of melatonin. Most smartphones nowadays have blue light filters, which of course must be used to achieve a positive effect. Ideally, electronic devices are switched off 1-2 hours before going to bed. (Image Source: depositphotos / antgor90)

What else can we do besides wear glasses?

In an ideal world you’d shut down all screens at least an hour before bed, if not 2 hours. But for those who can’t—or won’t—do that  apps could help.

These apps  – like f.lux and Night shift mode for Apple products – block blue light at night. If you can’t step away from screens at night completely and don’t want to buy glasses, apps that change the light emitted by a display seem to help although there is very little data on them.

To summarize: Blue light can disrupt sleep by altering melatonin levels. We can do two things to help mitigate this: wear blue light blocking glasses and use apps that have night mode to reduce low wave light emission close to bedtime.

How do we improve sleep?

In conclusion, naps of 20-30 minutes can help improve performance and cognition independent of sleep debt or sleep loss. Furthermore, blue light can disrupt sleep and two methods to help resolve this issue are to wear blue light blocking glasses and using night mode on your devices. Ideally, you would not be on electronic devices within 1 hour of bed.

Please feel free to reach out to me if you have any questions.

Title Image Source: Fotolia / stockasso