…you would have found me wearing a set of light-emitting earbuds that look just like a small set of headphones.
As a way to reduce jet lag, shift my circadian rhythm forwards or backwards for sleep enhancement, and increase my mood in the absence of sun, I've been experimenting with biohacking my circadian rhythm using a tiny stream of light to directly target the photoreceptors in my brain through both my ears.
In this post, you're going to learn exactly how you can utilize this technique yourself using a device called a “HumanCharger“. Enjoy.
What Is Light, Exactly?
OK, you may think you know what light is, but to really understand the rest of this article and to get the most out of your light biohacking experience, let's make sure you have a nerdy, propellor-hat understanding of light, shall we?
Light is electromagnetic radiation that specifically falls within a certain part of the electromagnetic spectrum. The word “light” usually refers to visible light, meaning light that is visible to your eye and is responsible for your sense of sight. Visible light is specifically defined as light that has a wavelength in the range of 400 nanometers (nm), which falls just between infrared light (which is light with longer wavelengths) and ultraviolet light (which is light with shorter wavelengths).
So for the purposes of this article, when I say “light”, I'm referring to visible light. If you feel grumpy that you don't get to learn about infrared light today, then fear not. I have a monster post coming soon that fills you in on that topic.
The main source of light on earth is, you guessed it, the sun. Sunlight provides the energy that green plants use to create starches, which then release energy into the living things that digest those starches. This process of photosynthesis provides just about all the energy used by life on earth.
Another important source of light for humans is fire, which includes everything from ancient campfires to modern kerosene lamps. Of course, with the development of electric lights and power, electric lighting has pretty much replaced most firelight.
Some species of animals generate their own light, called bioluminescence. For example, fireflies use light to locate mates, and vampire squids use light to hide themselves from prey.
The specific properties of light are generally measured in terms of intensity, propagation, direction, frequency or wavelength, and polarization. The speed of light, measured in a vacuum, is 299,792,458 meters per second, and is one of the fundamental constants of nature. Visible light, as with all types of electromagnetic radiation (EMR), is experimentally found to always move at this speed in vacuum.
Hope you remember all that. There may be a test later.
Another Thing You Need To Know: The Circadian Rhythm
Just as crucial as your understanding of light is going to be your understanding of the circadian rhythm.
Circadian rhythms are physiologic and behavioral cycles with a recurring periodicity of approximately 24 hours, generated by an endogenous biological pacemaker called the suprachiasmatic nucleus (SCN), which is located in the anterior hypothalamus in brain. These circadian rhythms control a huge variety of biological processes, such as sleep- wake cycle, body temperature, feeding, hormone secretion, glucose homeostasis, and cell-cycle regulation.
The timing of these physiologic rhythms can become altered, leading to changes in the phase relationship of rhythms to each other, which can cause internal desynchronization. Sometimes this desynchronization manifests as jet lag, sometimes as insomnia, sometimes as waking up extremely freaking early even though all you really want to do is just sleep in a little bit. As you may have experienced at some point in your life, a loss of coordination of these rhythms can have negative consequences on your productivity, your appetite, your happiness, you social interactions, your workouts, your focus, your immune system and many other physiologic and behavioral functions.
So ultimately, the less desynchronized your circadian rhythms are, the better your life. This is mostly related to a big disruption in the production of monoamines and hormones that affect your sleep-wake cycle and wellbeing, such as melatonin, serotonin, dopamine, noradrenalin, leptin, ghrelin, etc.
Via a process called “circadian entrainment”, circadian rhythms are synchronized with the earth’s rotation by daily adjustments in the timing of the SCN (remember, that's the part of your brain I mentioned earlier), and the circadian rhythms generally follow the exposure to stimuli that signal the time of day. These stimuli are known as zeitgebers (German for ‘‘time-givers’’), and while zeitgebers can include everything from the time of day that you exercise, to when you eat breakfast…
…light is the most important and potent stimulus for circadian entrainment.
The magnitude and direction of any changes in circadian rhythms directly depends on when within the circadian rhythm that a light pulse is presented to either your eyes, or your skin, or anywhere else on your body that light photoreceptors are located. You can actually plot phase changes in circadian rhythm according to the time of light stimulus presentation, and this plot provides what sleep scientists call a “phase response curve”.
For example, exposure to light in the morning and exposure to darkness at night results in a phase response curve that can shift your circadian rhythm backwards and make you sleepy at a more appropriate time in the evening, while exposure to light in the evening or non-exposure to light in the morning can slightly shift your circadian rhythm forwards and cause you to stay awake longer and possibly sleep in longer in the morning, although sleeping in longer in the morning usually requires more of an absence of morning light than a presence of evening light.
What Happens When Your Circadian Rhythm Gets Messed Up
Circadian rhythm sleep disorders (CRSDs) is the term given to patterns of sleep-wake rhythm disturbances. CRSDs result from a misalignment between the timing of the circadian rhythm and the external environment (e.g. jet lag, shift work, watching loud and bright TV at night, etc.) or a dysfunction of the circadian clock and its afferent and efferent pathways (e.g. delayed sleep-phase, advanced sleep-phase, non-24-hour, and irregular sleep-wake rhythm disorders, such as might occur with obstructive sleep apnea, parasites, nighttime hypoglycemia, etc.).
The most common symptoms of these disorders are difficulties with sleep onset or sleep maintenance, and excessive sleepiness that is commonly associated with impaired social and occupational functioning.
Effective treatment for most CRSDs requires a multimodal approach to accelerate circadian realignment with exposure to appropriate amounts of light at specific times of day, avoidance of bright light at inappropriate times, adherence to scheduled sleep and wake times and some of the other strategies Dr. Joe Zelk discusses in this article and this podcast.
If you want more nitty gritty details, you can download Circadian Rhythm Abnormalities (.pdf download). I also talk quite a bit about circadian rhythms in the article “5 Biohacks To Beat Insomnia, Sleep Better On Airplanes & Shut Down Stress”.
OK, let's sum up where we are at this point:
You now understand now that light is the single strongest signal that keeps your biological clock synchronized.
You understand that if you don’t get enough light during the day or you get it at the wrong time of the day, e.g. during shift-work or travel induced jet lag, your biological clock can go out of sync, and the production of neurotransmitters and hormones that affect your sleep-wake cycle and wellbeing.
And you understand that this can have a negative effect on how you feel and function during the day and how you sleep during the night.
You've Got Light Receptors All Over Your Brain
The information your body gets about existence or absence of light is received via light-sensitive receptor proteins in the eye's retina. These proteins are called opsins. Opsins convert the photonic energy of light into electrical potential in neurons, and project signals from light to the brain's biological clock, as well as to other brain areas. This then increases neurotransmitter signalling and influences hormone production.
But here's what most people don't know: light-sensitive receptors are not only found in the retina, but also in many locations in the brain, such as the cerebrum and the hypothalamus. I came across this in an independent, up-to-date inventory of human proteins, including the light sensitive proteins in brain tissue that is maintained by the international Human Protein Atlas project, managed by Uppsala University of Sweden, and funded by the Knut & Alice Wallenberg foundation.
In several recent studies, light sensitive receptors have been found in many locations in the human and animal brain, receptors that are shockingly completely separate from the retina. For example in one study, human post-mortem brain and peripheral tissue was analysed for the presence of two of the most relevant opsins, melanopsin and encephalopsin, that are sensitive to visible light. Results showed the presence of these opsins at 18 different sites of the human brain and peripheral tissue, indicating light-sensitivity in the brain itself.
In another study, 50 healthy people were randomly divided into two groups, one of which one received 12 minutes of gentle light exposure in their ears via earbuds very much like headphones, and another group that received no light (e.g. lightless earbuds). During the light exposure in the ear, a functional magnetic resonance imaging (fMRI) scan of each group's brain activity was conducted.
The intriguing results showed a significantly increased activation of the visual and sensory-motor areas of the brain in the group that had received light in their ears, compared to zero activation in the placebo control group. This means that there is a photosensitivity of the brain that is completely independent from the eyes. Based on this result, the idea emerged that a disorder like Seasonal Affective Disorder (SAD), which is already treated with bright light therapy like desktop blue light boxes, could just as easily be treated by directing small and portable amounts of light directly to the brain, through the ears.
This all makes sense, since SAD is primarily caused by seasonal lack of exposure to sufficient light. It is characterized by all the usual symptoms of depression, and also an increased need for sleep, annoying fatigue, craving for carbohydrates and weight gain, especially during darker winter months or times of gray, sunless rain.
The earliest bright light headset clinical studies investigated whether transcranial light via the ear could reduce depression symptoms in people suffering from SAD. In the first of these pilot studies, 13 SAD patients were subjected to a daily dose of 8-12 minutes of transcranial bright light therapy into their ears for four weeks. Their depression and anxiety symptoms were measured using standard questionnaires like the 17-item Hamilton Depression Rating Scale, the Beck Depression Inventory, and the Hamilton Anxiety Rating Scale, both prior to the 4 week trial and afterwards.
When researchers compared the depression and anxiety score before treatment and after the fourth week, the results showed a significant reduction in reported symptoms on all three measures. These findings suggest that transcranial bright light therapy could be an alternative to traditional light therapy.
Then, in a second, larger four week trial, 89 patients suffering from SAD were randomly assigned to one of three treatment groups and received either a low, medium, or high dose of daily bright light in their ear for a total of 12 minutes each morning. Depressive symptoms and cognitive performance were again assessed using standard psychiatric instruments at the beginning, during, and at the end of the trial. Results showed a significant reduction of depression symptoms in 74-79% of the patients in all three treatment groups as well as a significant improvement of cognitive performance compared to baseline. The result was comparable with any traditional bright light lamp and blue light boxing studies conducted over the past two decades, and suggest that light shone into the ear can alleviate depression symptoms in SAD patients, and can also increase cognitive performance.
And that's all without you having to stare at a giant blue light box emitting light placed in your bedroom or on your desk, which is the standard treatment for SAD, and even something I've personally recommended in the past as a way to align your circadian rhythm, such as in my Red Light and Blue Light Biohacking Tips podcast.
So it turns out that your ear canal is actually a very convenient passageway for light to reach photosensitive brain areas. This is because the light only needs to travel a short distance to reach for instance the light sensitive receptors in cerebrum. Light can literally passes through the translucent eardrum and the thin bone structures in your ear, and then immediately activate relevant neural networks of your brain.
That's right: your freaking ear can sense light.
Enter The Human Charger
A company called “Valkee“, based out of Finland, spearheaded much of the research you just read about on the ear's ability to detect light, and they've specifically investigated how light shining directly into your ears can do things like treat jet lag and SAD, assist with morning wakefulness, and shift circadian rhythms forwards or backwards.
Motivated to fight through the long, dark winters of their home in northern Finland, scientist Juuso Nissila and engineer Antti Aunio launched Valkee in 2007. In 2010, they developed a bright light headset-based medical device designed specifically to prevent and treat SAD. This is the same in-ear device used in the studies cited above.
Although the Valkee ear light device was initially developed for the treatment of SAD, the logical next step in the development of this technology for medical uses was to show that it could improve your wellbeing, increase cognitive performance, decrease anxiety, or be used to biohack circadian rhythms and address jet lag, rather than just treating SAD.
So Juuso and Antti designed a study to investigate whether an in-ear light headset could reduce moderate anxiety symptoms, even in the absence of SAD. Anxiety is associated with SAD, and other studies on SAD have already given insight into potential benefits of transcranial light for treating anxiety. So Valkee ran a small-scale, randomized, sham-controlled, double-blind trial on acute treatment of anxiety with 28 participants randomized into two groups.
In November 2013, the results were presented in The International Forum on Mood and Anxiety Disorders in Monaco, and showed that when comparing pre and post light exposure, anxiety symptoms were significantly reduced in the ear light treatment group, with zero significant change in anxiety symptoms in the placebo group. This study was the world's first fully double-blind, placebo-controlled study with any bright light device, including bright light lamps or blue light boxes (these kind of devices obviously can't be tested without the participant knowing whether the light is on or off).
But human well-being is not only about treating disorders, or about the absence of disease, right?
It also includes physical and cognitive performance, and the ability to perform at optimal levels even when you're already feeling fine. So Juuso and Antti decided to investigate whether transcranial bright light treatment would be able to improve aspects of cognitive performance such as psychomotor speed in elite pro ice hockey players.
In this study, a series of psychomotor speed tests, including mean reaction time and motor time (using audio and visual signals) were administered to the Finnish National Ice Hockey League team before and after 24 days of transcranial bright light or sham treatment. The treatments were given during seasonal darkness in the Oulu region of Finland, when the strain on the players was also very high (10 matches during 24 days).
A daily 12 minute dose of bright light or sham treatment was given every morning between 8am and 12pm to the hockey players, at home with the Valkee transcranial (in-ear) bright light device. Not surprisingly, Juuso and Antti found that psychomotor speed, particularly motor time with a visual warning signal, significantly improved after the series of 12 minute long bright light treatment in the eras of professional ice-hockey players during the competition season in the dark time of the year.
What Can Light In Your Ears Do For Jet Lag?
But let's say you're not a professional hockey player, and you also don't struggle with depression or seasonal affective disorder.
I'm guessing you're still going to be a bit intrigued by the sleep and jet lag component of using in-ear light.
As you probably know, rapid travel in an airplane over several time zones usually results in something that scientists call “passing de-synchronization”, but that we normal folks call “jet lag”. It arises due to a sudden significant difference between environmental time and the biological clock of the traveller.
Symptoms of jet lag include sleep disturbances, drowsiness during the day, reduced alertness, poor overall performance, cognitive deficits, fatigue, irritation, anxiety, depression, and gastrointestinal dysfunction. The severity of jet lag symptoms depends on the number of time zones crossed, the direction of travel, the time of day of the flight, and possibly even the time of year, as well as individual parameters such as age, chronotype, and physical health. Jet lag symptoms tend to dissipate as your internal biological clock gradually shifts toward the time of your new time zone.
But this adaptation takes time – on average one full hour of time zone difference per day spent in the new time zone. So this means if you fly across three time zones it takes you a full three days to fully adapt. And if you fly across the Atlantic or Pacific, it could be 7-10 days for you to fully adapt.
There are only a few random studies that have explored light as a countermeasure to treat the symptoms of jet lag. These studies have shown a modest circadian rhythm entraining effect and increased sleep effectiveness, but show absolutely no effect on regaining performance or a decrease in actual jet lag symptoms.
So Valkee set about organizing a randomized, placebo-controlled, double-blind jet lag field study of 55 trans-Atlantic travelers, specifically to investigate whether intermittent light exposure from a headset's ear buds could significantly alleviate jet lag.
Study participants were randomly divided into a light treatment group and a placebo group. The participants travelled by plane from Finland to North America and back, and to allow their internal clock to adjust to North American time. spent at least one week on the ground in North America before their flight back.
During the treatment period immediately after returning to Finland, participants received bright light or placebo headset treatment four times a day at pre-determined times. Jet lag symptoms were measured using several well-established metrics likethe Karolinska Sleepiness Scale, Horne-Östberg Morningness-Eveningness Questionnaire, Visual Analogue Scale, State Trait Anxiety Inventory and the Profile of Mood State score (who names these things?). These are the same scales used in all seven light-based jet lag field studies that have been published in the last 15 years.
So what happened?
In the bright light treatment group, the jet lag symptoms decreased significantly faster than in the placebo group. None of the 55 subjects in the present study reported any adverse effects as a result of the light treatment. As a matter of fact, the bright light group participants’ recovery back to their baseline condition, measured before the flight, took on average only half as long compared with the placebo group.
This is the first ever randomized, placebo-controlled and double-blinded light therapy study on alleviation of jet lag symptoms, and the results indicate that transcranial bright light given through ear canals decreases symptoms of jet lag.
The results of the new study were published in the April 2015 issue of Aerospace Medicine and Human Performance. The peer-reviewed monthly journal published by the Aerospace Medical Association (AsMA) is the most used and cited journal in its field and distributed to more than 80 nations.
Based on the study results and other required qualifications, in April of 2015 Valkee's in-ear light device, quite appropriately called “The HumanCharger“, was granted the EU medical device CE-certification under Council Directive 92/43/EEC, expanding the Company’s existing EU medical device certification for treatment of Seasonal Affective Disorder (SAD).
The device (pictured below, right) is a tiny, pocked-sized headset about the size of a small .mp3 player, with accompanying earbuds that are exactly the size of regular audio earbuds, but that produce a beam of light rather than producing sound.
1) exposure to bright light;
2) melatonin supplements;
3) pharmacological agents – that is, medication.
Of all these three options, only bright light exposure has none of the side effects or risks known to be associated with the use of melatonin or pharmacological agents used to treat and avoid jet lag symptoms.
Since April, Valkee has continued pioneering research to reduce jet lag, enhance sleep, and help people feel better, with a goal to enhance cognitive performance while decreasing the need for anti-depressants or other medicines.
My Experience With The HumanCharger
In May, I got my hands on my own HumanCharger (Valkee sent me a trial unit). Although the model also comes in silver, mine is a sleek little black device, about 1/4 the size of my cell phone and 1/2 as thick.
The last time I messed around much with biohacking light was when I wrote an article on blue-light blocking called “The Ultimate Visual Biohack – How To Create Your Own Set Of Custom Vision, Performance & Sleep Enhancing Glasses.
But ear light exposure has been a whole new experience for me.
Here's how it works:
1) You put the earbuds in your ears.
2) You push the one, single button in the middle of the device.
3) The lights automatically turn on, shine for a total of 12 minutes, then turn off.
I don't feel a thing in terms of actual warmth or sensation, although I immediately feel a slight surge of alertness when I turn on the device and during the entire 12 minutes that the protocol is running. This is the same sensation I feel if I step outside into the sun, or suddenly switch on a light in a dark bedroom. It is kind of a weird feeling, since you never really think of the inside of your ears as being able to “see” light.
So how have I been using my HumanCharger?
First, exactly according to the instructions from Valkee, for the 1-3 days before I travel from East to West across multiple time zones, I do 12 minutes of the light protocol when it's morning where I'm going. So if I want to be wakeful at, say, 7am in the West, I'll use the light at 10am in the East.
Then, when I'm in the West, I simply blast the light in my ears for 12 minutes either when I wake up or while I'm sitting drinking coffee and checking my emails.
So far, with this technique, I've used the HumanCharger for three separate trips and experienced absolutely zero jet lag on any of the trips. My only regret leading up to writing this article is that I have not yet had a chance to use the HumanCharger for an international flight, but I have a whole slew of international travels coming up this fall during which I plan on using it to avoid all the grogginess, food cravings, and decrease in cognitive performance that happens when crossing a significant number of time zones.
Next, I've had two races for which I've had to wake up 1-2 hours before my normal waking time. In both instances, I've instantly eliminated the normal grogginess from getting up earlier than usual by simply using the HumanCharger as soon as I wake up in the morning.
Next, on two separate occasions, I've taken out the HumanCharger on a sunless day and used it just after lunch, when afternoon sleepiness and mild amounts of seasonal affective disorder would normally set in. Both times, it's completely eliminated the need for a nap, and although it could certainly be a placebo effect, seems to lift my mood, focus and cognitive performance as well.
I've also had several times since getting my HumanCharger that I've gotten into a pattern of waking up at about 5:30AM, when I'd rather sleep until 6:30AM. Each time, I've pulled myself out of that pattern by getting up at 5:30AM, avoiding any sun exposure, then at 6:30AM (the time I'd rather be waking up), putting myself through the HumanCharger protocol. So in this way, I can shift my circadian rhythm forwards, or backwards.
Finally, although I haven't yet had the opportunity to use it for this purpose, the HumanCharger could be used when you've traveled to, say, the West. Let's say you have a party, a dinner, a social event, a conference, a speech, a meeting, etc. at 7pm, which for you, if you come from the East, would be, say, 10pm. You could use the Human Charger beforehand for a quick blast of energy as an alternative to caffeine or some other stimulant. However, I've actually avoided using it in a situation like this, since I don't really want to shift my circadian rhythm too far forward in the evening. I just like my sleep too much.
Oh yeah, one other thing…there's an app too.
In case my description and instructions were too vague, the HumanCharger App basically tells you the exact best times for your 12 minutes bursts of ear light, based on your origin and destination time zone, including the option for getting these instructions via push notifications. It integrates with travel sites like TripIt, so you don’t need to enter again the details of any of your trips. This means the app can grab your flights from TripIt and tell you exactly when to use your charger. It also has a nifty time zone difference visualizer on it. You can get the app here.
Suffer from anxiety or seasonal affective disorder?
Travel frequently and struggle with jeg lag?
Confused trying to figure out how to shift your circadian rhythm forward or backward?
Need a non-pharmaceutical, non-medicinal, non-supplement alternative to caffeine or energy drinks?
I recommend you try treating your ears with light for 12 minutes using The HumanCharger. The instructions that come with it are easy to understand, and it's light, portable, travels anywhere, and is far less awkward at coffeeshops than lugging around a giant blue light box to slam on the table in front of you. Basically, it just looks like you're listening to music or a podcast.
Enjoy, and leave your questions, comments and feedback below.
Also published on Medium.