WHY AM I TIRED? 10 COMMON CAUSES OF FATIGUE
(number 5 will surprise you)
Fatigue is characterised by a general feeling of low energy and a chronic tiredness that doesn’t go away even if you rest more. Fatigue and tiredness are becoming increasingly common in the general population, a 2021 study (DOI 10.3238/arztebl.m2021.0192) found that prevalence of fatigue in Europe varies from 20 to 38% of the population.
The severity of fatigue can range from light to mild and extreme, and the first step into recover is to find out the root cause. In this article I explain the 7 most common that I’ve encountered in my clinic, and it could give an idea of which one might apply to you.
7 COMMON CAUSES
1-STRESS. Our modern lifestyle exposes us constantly to stressors such as less rest, more noise from traffic to TV, too much information from medias at our fingertips and reduced family support. This is on top of the stress from work, finances and relationships. This is why is not unusual to feel overwhelmed sometimes.
The stress response is activated in the brain as soon as we perceive a threat, but what 2000 years might have been experience as threat is very different from today. Whilst back in pre-historical times a threat looked like a wild animal trying to kill us, today could be anything from a deadline at work, to feeling overwhelmed at work/at home or a presentation. The adrenal glands, 2 small fist-sized glands on top of the kidneys, produce hormones (cortisol and adrenaline mostly) in response to stress. The 2 hormones have a short-term repercussion on blood sugar levels, blood pressure, fat breakdown and muscle tension, on top of suppressing appetite and digestion. All is well when the threat is over and the body goes back into normal function, but when stress goes on for a prolonged period the adrenal glands eventually get exhausted, your body starts to struggle to cope and this can influence sleep quality, energy, digestion, bone formation, thyroid function, reproduction and immunity.
2-LACK OF SLEEP. This is a well-known cause of low energy and fatigue, but often overlooked. How many hours do you sleep per night? Do you sleep well? Do you struggle to fall asleep? Do you wake up often? Do you wake up not refreshed? It is recommended that we sleep between 7 and 9 hours a day and any less on a regular basis can affect not only energy levels, but also memory and concentration, mood, the immune system, weight gain and more.
3-UNEVEN BLOOD SUGAR. Although carbohydrates are a key macronutrient that the body needs to produce energy, too much simple carbs can have the opposite effect. Simple carbs are foods like white bread, pasta, cookies, sugary drinks that when eaten, release quick energy to the body by flooding the blood of sugar. If we utilise the carbs by doing some sort of physical activity then blood sugar will rapidly stabilise, but if the amount of these carbs exceeds your needs, then we can experience high energy shortly after eating, followed by a crash (too much insulin is produced, with a feeling of drowsiness. When our blood sugar has peaks of highs and lows, then we might feel ready to climb a mountain one moment and wanting to sleep the other. This is the classic energy dip after a simple carbohydrate-rich meal.
4-ANAEMIA. The most common type of anaemia is the iron-deficiency one and should be the first to be investigated when suffering from tiredness and fatigue. Iron is an essential nutrient that we take from food, it attaches to oxygen and transport it around the body to all tissues and organs. At times our intake can be low due to dietary intake (particularly with vegans and vegetarian diets), poor nutrient absorption or high blood loss during menstruation. Other times an individual can be predisposed to low iron due to genetic variations. This is why is important to test the levels of this important nutrients when we experience fatigue. There are also other types of anaemia, like the megaloblastic type that results from low levels of vitamin B12 or folic acid, making the red blood cells bigger than usual.
5-DEHYDRATION. As we are made of roughly 60% of water, it is not surprising to find out that dehydration can contribute to fatigue and tiredness. Adequate water levels dilate the arteries, promoting blood flow, blood can then carry oxygen and nutrients all over the body, making you feel more energised and focused. Even mild dehydration can cause symptoms like headaches, tiredness and poor concentration. Pay particular attention at your water intake while being in a hot climate, performing sport or spending a lot of time outdoors.
6-IMPAIRED THYROID. The thyroid is a gland situated in front of your neck and thanks to the hormones that produces regulate the metabolism (how efficiently we transform food into energy). Both hypothyroidism and hyperthyroidism can result in fatigue, although because of 2 different mechanisms. Hypothyroidism, low thyroid function, slows down metabolism, contributing to weight gain, fatigue, hair loss and more. Hyperthyroidism on the other hand is high thyroid function, which speeds up metabolism and can overwhelm the body, leading to weight loss, fatigue and rapid heartbeat. The thyroid gland also interacts with other systems of the body, for example with the cardiovascular system, by regulating how much blood is pumped, the heart rate and heart contractions; and the digestive system, by regulating motility, which is how fast or slow the food passes through the digestive system.
7-SUBOPTIMAL NUTRIENT INTAKE. The body needs a certain number of vitamins, minerals and phytonutrients (chemical compounds found in plants) to function optimally. Unfortunately, as a society, we are consuming less and less colourful, nourishing foods. We often opt for a beige diet (white pasta, bread, flour) that has a poor nutrient intake. The problem is that if the body doesn’t get enough nutrients, it cannot function properly, and over time we start to experience complains such as fatigue.
WHEN TO SEE A DOCTOR
If your fatigue is accompanied by any other symptom, like unexplained pain/weight loss/change in bowel habits, depression and more, I advise to talk to your doctor. It is important to recognise that sometimes is better to speak to your healthcare practitioner before embarking in diet and lifestyle changes.
If you feel that something is off, or if you have other symptoms along with fatigue, then a visit to your doctor for an examination is always the best thing. A good idea is to start a journal where you can write down your symptoms daily, along with sleep, exercise and food intake. This method is often very useful to recognise any pattern between the symptoms and your lifestyle. You can download my free Wellness Tracker here.
Beehan-Quirk C. Jarman L. Maharaj S. et al (2020). Investigating the effects of fatigue on blood sugar levels – Implication for diabetes. Translational Metabolic Syndrome Research, 3;17-20. doi.org/10.1016/j.tmsr.2020.03.001.
Fitzgerald MA (2008). Fight fatigue by evaluating thyroid function. The Nurse Practitioner, 33(12):6-7. doi: 10.1097/01.NPR.0000342172.25167.7d. PMID: 19057337.
Kocalevent RD, Hinz A, Brähler E, Klapp BF (2011). Determinants of fatigue and stress. BMC Research Notes, 20;4:238. doi: 10.1186/1756-0500-4-238. PMID: 21774803; PMCID: PMC3148561.
Rosenthal TC, Majeroni BA, Pretorius R, Malik K (2008). Fatigue: an overview. American Family Physician, 78(10):1173-9. PMID: 19035066.
Sobrero A, Puglisi F, Guglielmi A. Et al (2001). Fatigue: a main component of anemia symptomatology. Seminars in Oncology, 28(2 Suppl 8):15-8. doi: 10.1016/s0093-7754(01)90207-6. PMID: 11395847.