Tired And Sleepy All The Time? Common Fatigue Causes You Need To Know

Author : Ari Whitten
Medical Reviewer: Evan Hirsch, M.D



Do you find yourself constantly saying things like “I’m so tired,” “I’m so exhausted,” or “I hope for once I can get a good night’s sleep tonight?” If so, you are not alone. Fatigue and daytime sleepiness are quickly becoming common symptoms of a modern epidemic. Literally millions of people now ask themselves daily,  “why am I so tired all the time?”

So what’s behind this fatigue and daytime sleepiness epidemic?

Well, there are a number of medical conditions that can potentially be causing or contributing to your lack of energy, but there is one major cause of most people’s issues with daytime sleepiness and fatigue – a disrupted Circadian Rhythm. And this article is going to show you exactly what it is.

Common Causes of Feeling tired on a Regular Basis:


B12 Deficiency Anemia:

B12 deficiency is becoming more common today as many people avoid foods rich in B12, such as  eggs, meat, milk, and cheese. Many modern conditions of the gut (Crohn’s, celiac, leaky gut) can also impact our ability to absorb B12, which can cause anemia. If you notice symptoms such as a tingling feeling in the fingers and toes, a red, swollen tongue, clumsiness and imbalance, nausea, constipation/diarrhea, or thinking difficulties, get your B12 tested. A B12 supplement and a more careful diet can help. 1

Iron Deficiency Anemia:

Iron deficiency anemia causes great feelings of fatigue because fewer red blood cells are manufactured which deliver oxygen to the organs and tissues. Iron deficiency anemia is very common today as many people are eating less organ meats, red meat, eggs, and greens like spinach. You may want to get checked for anemia if you are also experiencing symptoms like pale skin, dizziness, a rapid heartbeat, shortness of breath, and/or dizziness. An iron supplement can typically fix the problem.2

Hypothyroid (Slow/Sluggish Thyroid):

A sluggish thyroid does not release enough thyroid hormone, which gives us energy and a normal metabolism. So often, people with a slow thyroid, gain weight and feel exhausted, have hair and eyebrow loss, dry skin, a hoarse voice, and cold hands/feet (plus many other symptoms). If you think you might have hypothyroidism, get to an endocrinologist or medical practitioner who can do a good hormone panel on you. 3

Epstein-Barr Virus (EBV) and other infections:

As many as 95% of all individuals harbor the EBV virus, also known as infectious mononucleosis, but few people actually contract it. In acute infections in adults, those who have it will feel completely exhausted and can sleep for 10 to 12 hours and still feel like they need more sleep. Complete exhaustion, nausea, swollen lymph glands and a painfully sore throat and fever are the hallmark symptoms of Epstein Barr Virus. Your doctor can test you for this. If you are all of a sudden very tired and that’s very abnormal for you, get checked for infections. It is also possible for EBV (and some other types of infections) to become chronic, so if you have daytime sleepiness/fatigue combined with chronic infection-related symptoms like a sore throat, swollen lymph glands, fever, trouble breathing, or strange neurological issues like tingling in your feet (for example), you should get checked for chronic infections.

Sleep disorders:

Another potential cause of daytime sleepiness is sleep apnea and other sleep disorders. If you wake up extremely tired even after sleeping for 8-9 hours, you may need to get checked for sleep apnea.


Diabetes can cause great feelings of tiredness for all kinds of reasons. Inflammation and cell damage are certainly factors, but the insulin resistance and blood sugar dysregulation are perhaps the bigger issues. Poor blood sugar regulation due to insulin resistance and poor diet are certainly big factors in energy levels. If you’re very overweight, it’s a strong possibility that you have issues with insulin resistance and blood sugar regulation. Please note that insulin resistance is highly reversible in the early stages with diet/exercise and other lifestyle strategies.4

Heart Disease:

If everything you do is making you feel exhausted, from walking up a flight of stairs to light tasks about the house, this could be an early sign of heart disease. If the heart is not performing up to par, it has to work extra hard to do its normal jobs of pumping blood to all your tissues, organs, and cells. This will make your heart and you very tired. So if you have heart disease (or suspect you might), this can certainly be a factor in fatigue as well.

All of these conditions cause fatigue and if you have one of these conditions, this may be the primary reason for your fatigue. But most people with fatigue and daytime sleepiness do not have these medical conditions, and their chronic fatigue is due to other causes.

Non-Medical Conditions:


Poor nutrition habits:

Eeating lots of processed, highly refined foods, low in fiber and high in sugar and fat causes chronic inflammation which directly inhibits orexin (a neuropeptide in the brain that regulates arousal, wakefulness, and appetite) and makes you feel lethargic and sleepy.

Fruits and Vegetables for fighting Fatigue

In 2014, researcher Mizuki Nobunaga and his team did several experiments where they discovered that a processed food diet directly reduces the number of orexin receptors in the hypothalamus. So not only will a processed food diet inhibit orexin, it will also reduce the effect of the orexin signal in the brain, making you feel tired and unable to perform physically and mentally. 5

Meal frequency and timing are also both very important in maximising energy and metabolism. But contrary to popular belief you should eat less often and earlier in the day. One of the most critical aspects of having high energy is training your body to efficiently use food as well as stored body fat for energy. Having Metabolic Flexibility means being able to go long periods of time without eating (and not having to rely on carbs for constant fuel). If you need to snack regularly in order to feel energetic, that’s a sign you have poor metabolic flexibility and an energy problem.

A study done on groups of overweight men and women showed that eating 3 meals as opposed to 6 meals of equal calories resulted in improved blood glucose control, increased metabolic rate and more satiation.6

Lack of movement:

Movement has a profound effect on neurotransmitters that regulate wakefulness. When you sit around a lot during the day, your body thinks it is time to rest and will start preparing for sleep. Small simple actions such as taking short movement breaks and walking more will increase your N.E.A.T (Non Exercise Activity Thermogenesis) and keep you alert and energised.


is another pervasive issue for many people experiencing fatigue. It is extremely common for people to simply not drink enough water. One recent study found that even being slightly dehydrated is enough to cause moodiness, problems concentrating, headaches and fatigue. In another study, women who were not sufficiently hydrated after exercise reported difficulty in getting work done and scored lower on questionnaires assessing mood. They also reported higher incidences of headaches and fatigue. This was with only mild dehydration, which could occur in normal life. 7 A similar study done in men showed; “In conclusion, mild dehydration without hyperthermia in men induced adverse changes in vigilance and working memory, and increased tension/anxiety and fatigue.” 8


Especially chronic stress, can cause or exacerbate many serious health problems, which result in poor mood and fatigue. Mood and energy are very much intertwined. Better moods facilitate better energy and vice versa. Stress causes the release of Cortisol from the adrenal glands, which over time loses its effectiveness. This results in out of control inflammation 9 which wrecks your immune system and damages mitochondria (the energy producers of the cell).10  Stress also depletes the Endocannabinoid System (the system in your brain responsible for shutting down the body’s stress response and re-establishing homeostasis) 11. [11] making it difficult to ward off fear and anxiety and decreases Thyroid Hormones  12. which are key in energy production, cognitive function and muscle function. Stress is associated with numerous medical conditions including, CFS, Fibromyalgia, IBS, Depression, Bipolar Disorder, ADHD, PTSD, SAD and even Alzheimer’s and Diabetes. 13 14 15.


Contrary to popular belief, when you drink coffee every day it doesn’t give you energy it actually wrecks your energy! Caffeine works by blocking the neurotransmitter, Adenosine, which normally makes you sleepy, thus causing a stimulant effect, which energises you. However, over time, your body fights this effect of overstimulation and produces more adenosine and adenosine receptors. This lowers your baseline level of energy and makes you dependent on caffeine just to make you feel normal. This is how you increase your tolerance/need for caffeine. Caffeine isn’t all bad though, it has been shown to have many health promoting and disease-lowering benefits. 16 If you really want caffeine to work for you, take a break from it from a while and then use it occasionally. For more information read “Coffee Is Secretly Sabotaging Your Energy Levels (Why Does Coffee Make Me Tired?)” https://energyblueprint.flywheelsites.com/why-does-coffee-make-me-tired/

The single most common cause of fatigue is Circadian Rhythm Disruption.

The Circadian Rhythm is a primary factor in regulating mood, motivation, body fat, metabolism, cellular regeneration and ultimately your energy levels! It is one of the body’s key regulators of health. It is the 24 hour biological clock built into your brain that is tied to the rise and fall of the sun. The outer world of light and darkness is linked to our inner world of hormones, mitochondria (our cellular energy generators) and neurotransmitters.

Our bodies respond to visual cues in our environment to release hormones and neurotransmitters that either power us up and wake us during the daylight or prepare us for sleep and repair in darkness. When light enters our eyes (specifically the blue light part of the spectrum), it triggers melanopsin receptors in our eye which are connected to the Suprachiasmatic Nucleus or SCN (which is the Circadian Clock area of the Brain).

When the SCN receives the blue light signal it initiates a whole cascade of neurotransmitter and hormone changes that get your brain and body into daytime, active mode. When the sun goes down, the lack of light entering your eye signals the brain to power down your body into nighttime, rest and sleep mode. The SCN sends the “no blue light” stimulus to the pineal gland, which is responsible for melatonin (a hormone that regulates sleep and wakefulness) production in the brain.This process starts putting the body into the physiological state of sleep.

Normally, when the sun goes down, melatonin goes up, and we get tired and ready for sleep. However, due to modern artificial light sources we have blue light pouring into our eyes for hours after sunset, and this completely throws off our circadian clock. It turns out that the modern world we live in is fundamentally mismatched to the signals of our biology.

Human beings are not designed to be indoors all day and then to be staring at all sorts of artificial light sources after the sun sets (such as indoor lighting, your smart phone, tv etc). Numerous studies have found that exposure to even regular room light during normal hours of sleep, reduces melatonin production by 50% thus negatively impacting your sleep and energy levels. 17 Because we are designed for an outdoor existence in tune with the rise and fall of the sun, most of us in modern society suffer from some degree of Circadian Rhythm disruption.

If you are struggling with sleep, understand that sleep quality and a lack of sleep is dependent on a strong Circadian Rhythm and so too are your energy levels! Both sleep duration and sleep quality determine how deep and restorative your sleep is on a cellular level, which means that even if you get enough sleep you can wake up tired if you did not get enough quality restorative sleep.

Statistics show that the effects of Circadian Rhythm disruption causing poor sleep are real and affect all of us. For example,

  • Today individuals sleep 20% less than 100 years ago.  18
  • Over 30% of the population suffers from insomnia. 19
  • Women are twice as likely to suffer from insomnia. 20
  • 40% of middle-aged adults report shorter sleep duration. 21
  • 50-70 million adults in the U.S. have a sleep disorder. 22

Circadian Rhythm disruption is also specifically linked to numerous conditions related to poor mood and energy levels, including; Chronic Fatigue and Fibromyalgia 23 24, Depression, Anhedonia (inability to feel pleasure) 25 and Daytime sleepiness. 26 27 28. To reset your Circadian Rhythm make sure you expose yourself to direct sunlight within 30 minutes of waking up and sleep in a cool, quiet and dark room at night.

The Bottom Line:

As you have learned, there are many possible causes and side effects for feeling tired and sleepy on a regular basis. It’s important to rule out medical reasons first, as fatigue often accompanies illness. However, most of the time, lifestyle changes such as what you eat, physical activity, and your sleep hygiene are responsible for your fatigue. Fixing your Circadian Rhythm, which is one of the primary causes of fatigue for most people, can have the most profound effect on overall energy levels. For more in depth information read “21 Reasons Your Fatigued (Fatigue Causes and How To Fix Fatigue)” https://energyblueprint.flywheelsites.com/fatigue-causes-and-how-to-fix-fatigue/


Like this article?

Share on Facebook
Share on Twitter
Share on Linkdin
Share on Pinterest
Medically Reviewed ByEvan Hirsch, M.D

Leave a comment

Scroll to Top