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9 most common causes of fatigue

9 most common causes of fatigue

9 most common causes of fatigue

Are you feeling tired all the time? Do you find yourself wanting to hit snooze more than usual?

Functional Medicine and clinical nutrition can help restore your energy by understanding the underlying issues that cause fatigue.

Exhaustion and low energy are often a result of what’s happening on the inside, or sometimes, the lack of what’s happening. 

What is fatigue?

Fatigue is a term used to describe an overall feeling of tiredness or lack of energy. It isn’t the same as simply feeling drowsy or sleepy. When you’re feeling tired all the time, you have no motivation and no energy. Being sleepy may be a symptom of fatigue, but it’s not the same thing.

While many people think that having low energy is a by-product of not getting enough sleep, it can be more serious and actually the symptom of Chronic Fatigue Syndrome.

Signs of chronic fatigue often include extreme tiredness that can occur following light movement or exercise. Poor decision-making, fogginess/memory loss, and cognitive decline may also be signs of a chronic fatigue issue.

Fatigue is an early communication signal from the body that something is amiss, but the causes of fatigue vary greatly.

What can cause fatigue? 

Treating fatigue varies according to the needs of each individual patient. Through thorough diagnostic testing for medical issues and a comprehensive evaluation of your lifestyle and diet, we can begin to understand what may be causing your fatigue. 


Fatigue may be caused by:

  1. Illnesses and health conditions 

There are many conditions that can cause persistent, unexplained fatigue that interferes with daily activities for more than six months.

These can include hypothyroidism, Lyme disease, asthma, diabetes, obstructive sleep apnoea, rheumatoid arthritis, fibromyalgia and heart disease.

  1. Chronic infections

Several studies have found that patients complaining of chronic fatigue have lab markers consistent with active pathogen activity and infection. These include stimulation of lymphocytes (a type of white blood cell involved in fighting infections), abnormal patterns of CD4+ and CD8+ T cells (which are also involved in fighting infections), and lymphadenopathy (an enlargement of the lymph glands consistent with infection). 

These infections may be either viral or bacterial.

  1. Diet imbalances and micronutrient deficiencies

Not eating enough or eating foods that are not nutritious can cause fatigue. If you eat foods that cause spikes in your blood sugar, as soon as those sugars drop, you feel fatigued. There are plenty of things you can do to help boost energy and ensure you’re eating a healthy, well-balanced diet. 

  • Try an anti-inflammatory diet or adding anti-inflammatory foods like fish and olive oil. 
  • Limit inflammatory foods like sugar, fried foods and processed meat.
  • Stay hydrated. While drinking more water isn’t a cure for fatigue, it’s still important. Dehydration is known to make fatigue worse. Staying hydrated is important for improving or maintaining health.
  • Limit your caffeine intake. Caffeine can give you a false sense of energy and lead you to overdo it. A little bit of caffeine may be fine for some people. Just be careful to not overexert yourself and make sure your intake doesn’t impact your sleep.
  • Many people with chronic fatigue often feel too tired to eat or don’t feel hungry. If you’re losing weight or struggling to eat enough throughout the day, try smaller meals more frequently or adding small snacks between each meal. Eating more frequently may help keep your energy up. Smaller portions may be easier to tolerate as well.
  • Decrease your sugar consumption. Sugar can also increase your energy temporarily, but the crash afterward can compound your tiredness. Instead of reaching for foods with refined sugar, eat naturally sweet foods with a bit of protein to help even out your blood sugar and energy levels. 
  • Fill up on nonstarchy veggies. Try to include vegetables of all colors throughout the day to get their unique nutrients and benefits. Red vegetables, for instance, are full of phytonutrients that act as antioxidants and help reduce inflammation. Yellow vegetables contain important vitamins and minerals like vitamins A, C and B6.
  • Limit processed foods. Heavily processed foods typically have fewer nutrients than their whole food counterparts. It’s important to load up on plants — like legumes, fruits, vegetables, and whole grains — to support your body’s needs. 
  • Include healthy fats. With a sprinkle of walnuts, a few slices of avocado, a couple of ounces of trout, it can be easy to add healthy fats like omega-3 fatty acids throughout the day. Healthy fats are important for brain and heart health, and they can also help reduce inflammation.
  1. Lifestyle factors

These can include:

  • physical exertion
  • lack of physical activity
  • lack of sleep
  • being overweight or obese
  • periods of emotional stress 
  • boredom
  • grief
  • using alcohol on a regular basis
  • using illicit drugs, such as cocaine
  1. Certain medications may cause fatigue as a side effect. 

These include blood pressure medications, diuretics, antidepressants, antihistamines, statins, proton pumps inhibitors, benzodiazepines, antibiotics and antipsychotics.

  1. Impaired methylation

Genetic mutations which affect the methylation pathway are associated with chronic fatigue. 

Defects in the methylation cycle can lead to both low levels of the active forms of folate and B12, and changes in folate and B12 metabolism. B12 and folate deficiency cause fatigue, and supplementation with B12 has been shown to have a positive effect in patients with fatigue. 

Find out more about the methylation process here

  1. Adrenal fatigue, also known as HPA axis dysregulation. 

The HPA (hypothalamic – pituitary – adrenal) axis is the structures in our body that help coordinate our stress response. Stress, whether emotional or physical, is defined as a real or perceived threat to our homeostasis. When we perceive that we are in danger, we have a fight or flight response that prepares us to either run away or stay and fight. In order to do this, our body releases hormones that cause our heart to beat faster, increase blood sugar to fuel your muscles, and increase rate of breathing, among many other responses. 

With considerable, ongoing stress, this system is activated too often. When it does not have time to rest, HPA axis dysregulation occurs. When this occurs the HPA axis, including the adrenal gland, will not work properly and will burn out. That is what we call ‘adrenal fatigue’ which causes a host of symptoms. 

Adrenal fatigue symptoms

  • Feeling irritable or depressed 
  • Frequent colds and illnesses
  • Difficulty coping with stress and/or experiencing an exaggerated response to a stress
  • Feeling unrefreshed even after a decent night of sleep
  • Tasks that may have been easy before now seem difficult  
  • Feeling “tired and wired”
  • Mental fogginess or sluggishness 
  • Craving sweet and salty foods
  • Dizziness when you stand up
  • Frequently feeling tired for no reason
  • Frequently feeling overwhelmed 
  • Low blood pressure
  1. Gut dysfunction

There are numerous pathologies related to gut health that are associated with fatigue, including small intestinal bacterial overgrowth (SIBO), chronic infections (bacterial, viral, parasitic), dysbiosis and fungal overgrowth, intestinal permeability and food intolerances.

There are several mechanisms that explain this connection:

  • Decreased absorption of nutrients required for energy production and normal physiological function
  • Abnormal immune function or response caused by disrupted gut microbiome
  • Chronic inflammation and oxidative stress
  • Impaired detoxification
  1. Hormones 

Several hormones can contribute to fatigue. 

Your thyroid powers every cell in your body through the hormones it produces, and these hormones power all of your metabolic processes and play a huge role in your energy levels, body temperature, and metabolism.

The two main hormones the thyroid releases are Triiodothyronine (T3) and Thyroxine (T4); any deficiency in these hormones can contribute to fatigue. 

The most common form of thyroid disease is Hashimoto’s disease, an autoimmune condition where your immune system attacks your thyroid, causing it to underproduce its hormones.

Chronic stress can also overwhelm the adrenal gland, crucial in producing and distributing hormones like Mineralocorticoids, Glucocorticoids and Testosterone into the bloodstream. These hormones are necessary for maintaining your salt levels, regulating your metabolism and your blood pressure. Low levels can lead to fatigue. 

Overcoming from it

Diagnosing and managing fatigue can be challenging as there can be many non-specific symptoms and underlying causes. Through a Functional Medicine approach, practitioners look for and test for these nine common issues.

At Advanced Functional Medicine, we take a holistic and personalised approach. We will look at your diet and lifestyle, as well as health issues that may be causing your fatigue. We successfully support many of our patients with supplements, including:

  • B complex with methylated B vitamins like methylfolate instead of folic acid
  • Many botanical herbs act as adaptogens, which are natural substances that help the body adapt to stress such as Asian ginseng, rhodiola, and ashwaganda. These herbs and supplements can support the body during a stressful time and help the body rebound.  

Call us or fill out the form for more information.

The above information is intended to be general, educational advice only, on topics which are of interest to us. It is not intended to represent specific or individual health or medical advice and is not specific to your situation. The below information is educative and is not intended to advertise any service.

Before making any decisions in relation to your health, you should always discuss your individual situation with your own health practitioners to ensure that any advice you have read is right for you.

Jarrod Cooper – ND

Jarrod Cooper – ND

Jarrod Cooper - ND is the founder of Advanced Functional Medicine Australia. He is a Naturopathic Doctor with extensive functional medicine training from leading practitioners in the USA and worldwide.

He is leading the way with advancements of functional medicine, clinically implementing worldwide best practices in Functional Medicine throughout Australia.

Jarrod consults in person from Perth, Western Australia and also online via Telehealth throughout Australia and worldwide.

If you are looking for personalised treatment, we highly recommend contacting Jarrod Cooper’s Advanced Functional Medicine clinic in Australia.

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