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5 reasons you can’t sleep (and how to fix each one)

Tips for sleeping better

It seems like everyone is having trouble sleeping these days, which is a problem, because if there is one basic thing we can all do to improve energy and focus throughout the day, it’s get good sleep at night. For me, there is no doubt that I am a happier and more productive person when I get my full 8 hours, and it turns out this has little to do with vanity.

Modern medicine is learning that lack of sleep, which the CDC defines as less than 7 hours a night for adults over 18, is at least partially to blame for a host of chronic health issues, such as increased risk for certain kinds of cancer as well as hypertension. John’s Hopkins researcher Patrick Finan even claims that poor sleep can increase the risk for heart disease and suppress the satiety hormone ghrelin, which is the signal to the body that it’s had enough food.

So, yes, sleep is a health issue that deserves to be front and center in every wellness discussion.

Why are so many of us having trouble sleeping? What is it about the modern world that has everyone talking about getting enough sleep?

Below, I share 5 common reasons you’re not falling asleep and what to do about each one.

You’re not genetically suited to caffeine

Let’s begin with some very basic biochemistry. ATP, or adenosine triphosphate, is the energy currency of the body, it is the literally gasoline for our cells. When we’ve burned up our ATP for the day, levels of adenosine, a compound associated with sleep, rise making us drowsy and signaling it’s time for bed. Bottom line is when adenosine reaches high enough levels, we’re ready for sleep. However, caffeine keeps us awake by blocking the adenosine receptors, which is why many people have a tough time falling asleep after a cup of coffee.

The levels of adenosine in our body, as well as the speed with which we metabolize caffeine, are both genetic. Some people are far better suited to consuming caffeine than are others. For example, the “C” allele of the ADORA2A gene is associated with caffeine induced insomnia, which makes sense because ADORA2A is responsible for making an adenosine receptor protein. Similarly, other genetic markers (the CYP1A2 gene in particular) are associated with slower caffeine metabolism, which means the effects of caffeine will be felt in some people for much longer than others. The impact of caffeine on slow metabolizers can be so dramatic as to increase their risk for a heart attack by as much as 36% when consuming caffeine, according to one study found.

Nearly half the population carries at least one copy of the “C” allele of ADORA2A which means many of us are simply not genetically suited to drinking caffeine and the effect is chronic lack of sleep.

Solution: If you can’t sleep, have your genetics tested, or just cut out the caffeine altogether and see what happens to the quality of your ZZZs. However, a word of caution: if you do decide to go cold turkey on coffee, watch out for caffeine withdrawal symptoms, I can attest first hand that they’re no joke.

Too much screen time

Humans are meant to operate on what is known as a circadian rhythm, which means we are awake when it is light out and winding down and sleeping when it is dark. The paleo diet is popular way of eating, but what about the way our ancestors experienced light? They certainly didn’t have light bulbs and gadgets to entertain them in their caves. And I don’t mean to be glib, the natural peaks and valleys of day and night have a big impact on how we sleep.

Just as ATP and adenosine ebb and flow based on the cycle of the day, so too do cortisol and melatonin, the wake and sleep hormones. Cortisol gets a bad rap as the “stress hormone,” but our body’s need cortisol to get up and going and take on the world for the day. It’s for this reason that cortisol levels are naturally at their highest in the mornings. However, as the day progresses and evening begins to bloom, melatonin slowly starts to rise so that we can go to sleep once it’s dark outside. The natural rise of melatonin is a key factor in helping us get to sleep.

But perhaps nothing disrupts this natural circadian balance more than the blue light we are constantly looking at on the screens of our TVs, smart phones and lap tops. Blue light is the anti-paleo light. The first studies looking at blue light and circadian rhythm were actually done in plankton, where the rhythms of these marine creatures were dramatically altered by blue light waves, but not light waves from different parts of the spectrum. Scientists initially believed that the human circadian clock couldn’t be influenced by light, but that view has changed over the last two decades. (R) It is now an accepted scientific fact that blue light blocks melatonin which reduces quality of sleep. Sadly, some research has even linked working the graveyard shift, characterized by exposure to blue light and a disrupted circadian rhythm, to increased cancer risk, but the connection hasn’t yet been definitively proven. (R)

For more, see The Unique Human Health Effects of Blue Light

Solution: try to avoid blue light exposure at least 4 hours before going to bed, or wear a pair of blue light blocking glasses if you must do late night work. Get the TV and phone out of your bedroom and designate the area as a sleep only zone. Change out LED lights (which emit large amounts of blue light) for incandescent bulbs.

Magnesium deficiency

More Americans are having trouble sleeping just as the rates of magnesium deficiency are on the rise. Coincidence? Maybe, maybe not. Like light, magnesium plays a role in regulating the circadian rhythm because it helps the body metabolize melatonin. In turn, elevated cortisol depletes magnesium levels. The combination of chronic stress and a lack of magnesium rich foods leaves us ill equipped to make the sleep hormone we rely on to get a full 8 hours sleep.

Solution: try a magnesium supplement about an hour before bed and see how you sleep. Many people find that a little magnesium (usually in the 250-500mg dose range) does wonders for their sleep, especially for deep sleep.

Allergies and glutamate

I’ve written before about how pollen allergies can cause anxiety, and we know that one of the ways histamine affects the central nervous system is by producing glutamate, an excitatory neurotransmitter. (R) In the neurotransmitter world, glutamate is the gas pedal, and GABA is the break, so anything that increases glutamate is not a friend to sleep. In fact, one of the often cited symptoms of histamine intolerance is insomnia and circadian disruption. (R)

To continue on the glutamate theme, variants in the GAD1 gene, which helps the body recycle glutamate back into GABA, are associated with early morning awakenings. Reduced GABA levels are linked to insomnia. (R) Since glutamate and GABA work in tandem, it’s also worth briefly noting here that for some sensitive individuals, glutamate in food and supplements may hurt sleep quality as well.

But aside from these more technical explanations, the physical symptoms of allergy, with the runny nose, itchy eyes, and congested airways are not a recipe for a good night’s sleep either. For example, allergic rhinitis and nasal congestion can increase the risk for sleep apnea.

So whether it’s the impact of histamine on your central nervous system, or simply a stuffy nose that is preventing you from sleeping, addressing allergies is an important step to take to get a better night’s sleep.

Solution: this is another area where it can pay to know your genetics. Variations in both the AOC1 genes, as well as the HNMT genes are associated with a reduced ability to clear histamine. Carriers of these polymorphisms may do best on a diet that is lower in histamine, especially if they’re located in a city where they suffer from seasonal allergies. For these folks, mast cell stabilizing supplements like L-theanine and quercetin can also be helpful.

From there, taking practical steps to remove allergens from the bedroom may also prove helpful. If you have a dog, have him or her sleep in the living room, not the bedroom. An air purifier is a must. Consider down alternative for your comforter and pillows, and encase both your mattress and pillows in a protective lining that repels dust mites and other allergens. I have gone on at great length about why I think it best to avoid mattresses with metal springs in my recent post about toxins in mattresses, however, another reason to opt for a good organic foam mattress over a metal spring mattress is that metal spring mattresses accumulate massive amounts of dust over the years.

Not enough bright light

I started out really wanting to have this section be devoted to exercise, as I know that getting out and moving has a big impact on my sleep quality. However, when I read the studies, it’s a mixed bag. Some studies claim that getting good sleep is a motivating factor for exercise rather than exercise contributing to sleep. For example, this study in the Journal of Clinical Sleep Medicine which found “results suggest that sleep influences next day exercise rather than exercise influencing sleep.” When they have been shown to work, exercise regimens are most effective for improving sleep quality, not as a quick fix, but over the period of about 4 months when they are consistently applied. (R)

But maybe it’s not just the physical movement of exercise that helps us sleep, maybe it’s the exposure to light. We have already established that too much light, especially blue light at night, isn’t helpful for sleep. Checking your phone right before bed is a recipe for disaster because the blue light blocks melatonin production and signals to your body that it’s time to head off to work, not to hit the sack.

However, bright light in the early morning appears to have the opposite effect by helping to regulate the circadian rhythm. In fact, bright light therapy has been used with some promise to help treat people suffering from insomnia. For example, this study, which found early morning light therapy combined with better sleep hygiene more effective at treating insomnia than either early morning or late afternoon exercise.

For more reading on light therapy and sleep, see:

The use of Light Therapy in the Treatment of Insomnia, and;

Therapeutics for Circadian Rhythm Sleep Disorders

Solution: As a practical matter, I think this one can be accomplished by getting out of the house and getting some good quality early morning sun without sun glasses. For those of you who live in northern climates and can’t get good sun during the winter, it may be worthwhile discussing light therapy with your doctor.


Today’s tech obsessed world is conspiring at every turn to disrupt our sleep patterns, however, as we’ve learned, keeping a focus on the mechanism behind a healthy circadian rhythm, as well as maintaining good sleep hygiene can go a long way to fixing most sleep problems. Perhaps the biggest change most of us can make for better sleep is to focus on getting good, bright light in the mornings (sans coffee) and avoiding blue light hours before we want to go to bed at night. That, and a little magnesium and you’ll be on your way to meet the sand man.

Did you try any of the tips listed in this article? How did they work for you?

John O'Connor

John O'Connor is the founder of Gene Food, host of the Gene Food Podcast and a health coach trained at Duke's Integrative Medicine Program. Read his full bio here.

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