Causes of Poor Sleep insomnia you May not Know About functional medicine

8 Causes of Poor Sleep you May not Know About

Dr Farah Sultan, MD, functional medicine doctor in Homewood, AL 35209 Dr. Farah Sultan, MD
Functional Medicine Doctor
Sleep Optimization Expert

Warning signs | Indoor environment | Sleep disruptors | Stress | Hormones | Medications | Insulin spikes | Gut health | Sleep apnea | References

You may have the best intentions to sleep well, but what can you do when you just can’t sleep? According to some estimates, around 30% of U.S. adults experience insomnia, with difficulty falling or staying asleep[1].

In this article, Dr. Farah Sultan, MD, a functional medicine doctor who specializes in sleep optimization by naturally balancing hormones, discusses some of the common underlying causes of sleep issues that are often overlooked. Learn about these warning signs and what can you do to improve your sleep.

The importance of sleep

The evidence to support the importance of sleep for your health is quite dramatic. Lack of sleep can have a negative effect on every aspect of your life. It can impact mood, energy levels, ability to think, focus, move, and communicate with others. In fact, lack of sleep is a major risk factor for chronic diseases such as cardiovascular disease, cancer, stroke, and dementia. It can also trigger metabolic issues such as insulin resistance and obesity[2]. And the list goes on and on.

The red flags of poor sleep

Poor sleep leaves plenty of signs and clues which you may feel during the night, but also during the day. It is important to recognize these signs and not mask them with medication or stimulants. Some of the common signs of poor sleep include:


  • Waking up feeling tired
  • You need an alarm clock to wake up and keep hitting the snooze button
  • It takes you awhile to get up
  • You need coffee to start your day.

During the day:

  • Memory issues, difficulties focusing, impaired problem-solving abilities
  • Low energy levels
  • Low productivity
  • Feeling sleepy throughout the day
  • Poor exercise recovery.

At night:

  • You find it hard to fall asleep
  • You wake up during the night and can’t get back to sleep.

Finding the cause of your sleep issues

You may find yourself feeling desperate for a good night’s sleep and be tempted to take sleep medications or use other drastic measures. Frankly, we have all been there, and I see this a lot in my medical practice.

It’s necessary, however, to address the root cause of sleep issues rather than cover up the symptoms with sleep aids. Not only it is highly debatable if these drugs do anything to improve the quality of your sleep, but they can also be highly addictive. For many of these medications, over time you develop a tolerance to them, and they stop working.

Even more, recent studies have shown that certain prescription sleep medications have been linked to increased risk of dementia and even cancer[3,4].

This is not a good strategy for long term quality sleep.

Common causes of poor sleep

There are many factors that can cause sleep issues that vary from one person to another. The good news, however, is that once you uncover the root cause and address it, you can achieve a great night’s sleep, even after many years of poor sleep.

With that said, here are some common variables that may affect sleep quality:

1 – Your indoor environment

A lot has changed since the days of our ancestors. Our time spent in nature has been drastically reduced, and we now spend most of our day and night indoors. This can impact our health in various ways, including disturbing our circadian rhythm and sleep patterns.

Blue light exposure at night

Before artificial lighting, the sun was the major source of light. We evolved in an environment where our sleep-wake cycles were determined by sunlight. We woke up naturally with sunrise and went to bed when it was dark. We were living in harmony with nature.

Modern times, however, have introduced a completely different environment with indoor lights. Now, for the first time in our evolution, we have light at night. Artificial lights are not the same as natural sunlight. According to the evidence, artificial light and in particular the blue light our electronic devices emit, suppress our natural melatonin production. This disrupts our biological clock and interferes with our sleep[5,6].

If blue light exposure is not something you can completely avoid in the evening, you may want to consider wearing blue light blocking glasses. These are not expensive and may offer an effective solution.

Indoor toxins

From the electromagnetic fields (EMF) radiation emitted from our cell phones, “dirty electricity” from other devices to the off gassing from your own mattress, internal environments often contain more toxins than the ones outside. All these indoor toxins can interfere with sleep.

Now, I know this may not be the easiest variable to address. But you can start by simply evaluating the number of electronics in your bedroom and consider removing those that don’t have to be there. Just reducing your exposure can make a difference.

Temperature and sleep

Is it too hot or cold to sleep? While the temperature in your bedroom may not be the first thing that comes in mind, studies have shown that lower ambient temperature is correlated with better sleep quality[7].

Now, there’s no perfect temperature that works best for everyone. The ideal temperature for sleep may vary from one person to another, although it appears that 68 °F (20°C) is a good place to start.

2 – Potential sleep disruptors in beverages

You start you morning with a delicious cup of coffee or take an extra cup just in case after lunch. But this not a problem since it will be out of your system by the evening, right?

Well, not exactly.

Due to its long half-life, even if you stop drinking coffee by noon, you still have plenty of caffeine in your system when it is time to go to bed. You may not feel energized during the evening, but it can still interrupt your sleep.

In fact, epidemiological studies and randomized controlled trials have shown that coffee and caffeine prolonged sleep latency, reduced total sleep time and sleep efficiency, and worsened perceived sleep quality[8].

The influence of caffeine on your sleep patterns is something to consider, even if you only drink one cup of coffee during the day. I find that it is very important to become aware of the number of stimulants you are putting into your body throughout the day. Other than coffee, energy drinks, herbal teas, certain supplements, or nicotine, can negatively impact your sleep, even if they are not used during the evening.

What about alcohol and sleep?

Many people like to drink alcohol before bedtime to help them relax and fall asleep. Paradoxically, however, as your body metabolizes alcohol, you may wake up during the night and end up with restless sleep. Even more, studies have shown that alcohol may also impair the body’s natural deep sleep patterns (REM sleep) which can have a negative impact on your learning and creativity the following day.

3 – Chronic stress

Cortisol, the primary stress hormone, is generally higher in the morning, and there’s a good reason for this. It increases our alertness and helps us wake up. At night, however, cortisol is low, so we can fall asleep.

With chronic stress or conditions like HPA Axis dysfunction (commonly known as adrenal fatigue), cortisol may be low in the morning but high in the evening. You then feel tired in the morning, but wide awake at night.

And this is where the plot thickens … Cortisol has an opposite relationship to the sleep hormone melatonin. When cortisol goes up, melatonin goes down. The rise in cortisol triggers the brain to respond with never-ending thoughts related to the stress you are experiencing at the moment. As a result, you wake up in the middle of the night with thoughts running through your head and have a hard time falling back to sleep.

4 – Hormonal changes due to aging

As we age, our hormone levels start declining especially after the age of 30. Women experience a decline in the hormones pregnenolone and progesterone, which impact sleep. The drop in these hormones also cause changes in memory, focus, and mood. In men, testosterone levels decrease with age, which can also impair sleep quality.

If this is a concern for you, work with your doctor to test your hormone levels. In my practice, I like to use natural bioidentical hormones, which are chemically identical to those the human body produces. (Keep in mind, however, they are not for everyone).

5 – Medications

Many medications can interfere with sleep, both prescription and over the counter. For example, the popular allergy medications Benadryl and Claritin are known to cause drowsiness for some people but may also lead to sleep issues. Stimulant medications like Adderall, often prescribed for Attention-Deficit Hyperactivity Disorder (ADHD) is another example of a medication that can interfere with sleep. Always speak with your doctor about the potential side effects before taking any medication.

6 – Insulin spikes at night

Rummaging through the fridge in the middle of the night?

Eating a sugary meal (or drink) too close to bedtime can cause your blood sugar levels to drop during the night, which can interrupt your sleep. This drop will wake you up as your brain will feel a need for more sugar. When blood sugar drops, many people find themselves in their kitchen in middle of the night, looking for something quick to eat, and the vicious cycle continues.

7 – Poor gut health

In case you are wondering how your gut can impact your sleep, the mystery lies in the gut-brain axis. This axis is a bidirectional communication between the digestive system and the brain. This means there is a direct link between the emotional and cognitive centers of the brain to the peripheral intestinal function[9].

When the microbiome in the gut is not functioning properly, it is unable to send the correct signals via neurotransmitters to the brain. This is because an unhealthy gut microbiome can decrease the natural production of neurotransmitters that play a role in sleep and stress, like serotonin, GABA, dopamine, and melatonin, impacting your sleep.

8 – Sleep apnea

Do you wake up at night gasping for air or snore loudly? You may have sleep apnea.

With this sleep disorder, your breathing stops and starts multiple times while you sleep[10]. Sleep apnea has been shown to increase mortality and morbidity because it impairs oxygenation to vital organs during sleep. If breathing during sleep is a concern, work with your doctor and get tested for sleep apnea. Breathing issues while sleeping increase your risk for many chronic diseases, in addition to preventing a good night’s rest for you (and possibly your partner).

Final thoughts

Proper sleep is essential for good health. If you are not getting the rest you need, whether you have trouble falling or staying asleep, the underlying cause should be addressed first. The good news is that once you uncover the root cause and address it, you can achieve a great night’s sleep, even after many years of poor sleep.

If you don’t know where to start, consider speaking to a functional doctor or healthcare provider who can help you discover the reasons you might not be sleeping. We all deserve a good night’s sleep, a simple lifestyle change may be all you need.

  1. Zohreh Yazdi, Khosro Sadeghniiat-Haghighi, Ziba Loukzadeh, Khadijeh Elmizadeh, Mahnaz Abbasi, “Prevalence of Sleep Disorders and Their Impacts on Occupational Performance: A Comparison between Shift Workers and Nonshift Workers”, Sleep Disorders, vol. 2014, Article ID 870320, 5 pages, 2014.
  2. CDC, Sleep and Sleep Disorders,
  3. Shih HI, Lin CC, Tu YF, Chang CM, Hsu HC, Chi CH, Kao CH. An increased risk of reversible dementia may occur after zolpidem derivative use in the elderly population: a population-based case-control study. Medicine (Baltimore). 2015 May;94(17):e809. doi: 10.1097/MD.0000000000000809. Erratum in: Medicine (Baltimore). 2016 Jun 19;94(24):1. PMID: 25929937; PMCID: PMC4603066.
  4. Sivertsen B, Salo P, Pentti J, Kivimäki M, Vahtera J. Use of sleep medications and risk of cancer: a matched case-control study. Sleep Med. 2015 Dec;16(12):1552-5. doi: 10.1016/j.sleep.2015.05.003. Epub 2015 May 27. PMID: 26116466.
  5. West KE, Jablonski MR, Warfield B, Cecil KS, James M, Ayers MA, Maida J, Bowen C, Sliney DH, Rollag MD, Hanifin JP, Brainard GC. Blue light from light-emitting diodes elicits a dose-dependent suppression of melatonin in humans. J Appl Physiol (1985). 2011 Mar;110(3):619-26. doi: 10.1152/japplphysiol.01413.2009. Epub 2010 Dec 16. PMID: 21164152.
  6. Tähkämö L, Partonen T, Pesonen AK. Systematic review of light exposure impact on human circadian rhythm. Chronobiol Int. 2019 Feb;36(2):151-170. doi: 10.1080/07420528.2018.1527773. Epub 2018 Oct 12. PMID: 30311830.
  7. The Best Temperature for Sleep,
  8. Clark I, Landolt HP. Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials. Sleep Med Rev. 2017 Feb;31:70-78. doi: 10.1016/j.smrv.2016.01.006. Epub 2016 Jan 30. PMID: 26899133.
  9. Carabotti M, Scirocco A, Maselli MA, Severi C. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol. 2015 Apr-Jun;28(2):203-209. PMID: 25830558; PMCID: PMC4367209.
  10. NHLBI, What is sleep apnea?
Dr. Farah Sultan, MD
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