Feeling tired is a near-universal experience, with around 20% of adults experiencing general fatigue, burnout, and lack of energy at least one point in their lifetime. While common, it's still not the most pleasant feeling, especially if you're tired for long periods at a time and experiencing disruptions in your normal day-to-day activities.
Understanding why you're tired is half the battle and in this blog, we take you through possible causes of chronic tiredness, and how they may affect your daily life. We also explore potential solutions and when you should see a doctor.
4 common causes of chronic tiredness
Feelings of tiredness usually come about due to one or a combination of the causes below. Consider whether your tiredness can be attributed to one or more of the potential causes listed here.
Sleep debt
One of the most common yet also most underestimated causes of feeling tired is not getting enough sleep. Sleep debt refers to the deficit between the sleep you need and the sleep you actually get, and measures not only time slept but also sleep quality. It's also accumulative and builds over weeks and months, not just last night. For example, if your body needs eight hours of sleep a day and you're only getting six each night, you're accumulating 14 hours of sleep debt in a week.
Sleep debt can cause tiredness and cognitive fog in a number of ways:
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Adenosine buildup: A chemical in the brain that creates sleep pressure during your waking hours that doesn't clear due to not enough sleep, leaving a compounding residual fog
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Disrupting hormones: Sleep regulates key hormones such as cortisol (stress), growth, ghrelin (hunger), and thyroid. Not sleeping enough throws these hormones off their balance
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Impairing glymphatic clearance: Glymphatic waste is cleared in deep sleep but with sleep debt, metabolic byproducts can accumulate and contribute to cognitive fog and fatigue
The most problematic thing about sleep debt is that people who suffer from it often cannot perceive how little sleep they are getting and how cognitive decline compounds over time. Short-term sleep debt is often fixable but research indicates that long term sleep debt accumulated over time can result in poor cognitive performance, increased sleepiness, poor mood, and a higher risk for accidents.
Nutrient deficiency
Nutrient deficiency is another commonly overlooked cause of tiredness as its effects can happen gradually and often without notice. Not having an adequately nutritional diet and specific micronutrients can slow down usable energy (ATP) production in your body.
Common nutrient deficiencies involved in feelings of lack of energy include:
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Iron: Low iron means less oxygen is delivered to the brain, causing effects like fatigue, weakness, and poor concentration
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Vitamin B12: Deficiency may cause fatigue that's linked to brain fog
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Vitamin D: A lack of vitamin D can cause fatigue, muscle weakness, and low mood
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Magnesium: Magnesium is used in the ATP synthesis process and hence low magnesium levels impair the body's ability to produce and use energy at a cellular level. Low magnesium may also disrupt sleep quality
Fatigue that results from nutrient deficiency tends to be constant rather than fluctuating, and may also be accompanied by physical body symptoms. The good news is, if this is causing your fatigue, supplementation may be a quick fix.
Lifestyle drain
Lifestyle drain is a term used to describe the cumulative toll of how you live your life day-to-day. Rather than a specific medical cause, lifestyle drain is often a result of many habits and circumstances compounded together. Lifestyle drain is also difficult to self-diagnose, requiring third parties to notice and identify as a potential cause of fatigue.
Some physical contributors to lifestyle drain are:
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Sedentary lifestyles: Not doing enough physical activity in your daily life reduces your capacity to generate energy and your baseline energy production capacity gradually declines (also occurs as you age)
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Poor diet quality: Linked with nutrient deficiencies as well as foods that contain refined carbohydrates and sugar that create energy spikes and crashes
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Alcohol: Disrupts sleep quality which causes tiredness the next day
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Dehydration: Impairs cognitive performance, mood, and perceived energy
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Caffeine dependency: Bodies that become regulated to caffeine require it just to feel normal, hence your lowering energy capacity without it
Psychological factors can also contribute to you feeling tired all the time, such as:
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Chronic stress: When experiencing stress, your cortisol spikes before returning to baseline. If you're constantly stressed, cortisol levels remain high which may affect general wellbeing and make restful sleep more difficult, making rest feel impossible
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Emotional labour: Constantly devoting energy to managing your emotional presentation to others can become a legitimate reason for tiredness and mental fatigue
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Lack of psychological rest: Increasingly common due to presence of social media and accessible entertainment channels, no down time for your brain can also cause fatigue (even when performing these activities doesn't feel tiring at first)
While lifestyle drain is often the hardest to identify as a cause of tiredness, it is also often easily fixable. Understanding the differences between healthy and unhealthy habits for your specific body can help you learn how to restore your energy levels.
Undiagnosed conditions
Chronic fatigue can be caused by more serious undiagnosed medical conditions such as:
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Thyroid disorders (conditions where the thyroid underperforms and slows down your energy)
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Blood sugar dysregulation (e.g. type 2 diabetes, insulin resistance, and reactive hypoglycemia)
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Sleep disorders (disorders that prevent your body from getting adequate rest such as obstructive sleep apnea)
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Anemia (conditions that reduce your body's ability to carry oxygen beyond iron deficiency)
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Mental health conditions (depression, anxiety disorders, and ADHD can cause fatigue by depleting mental and physical energy)
Undiagnosed conditions are as the name implies, difficult to identify and require a medical professional to conduct tests before solutions can be proposed. These conditions are usually considered when more common causes of fatigue (i.e. sleep debt, nutrients deficiency, and lifestyle drain) are ruled out.
When to see a doctor
While tiredness is somewhat normalised, it doesn't mean it's not a serious condition to see a doctor about. Tiredness may be a sign of an underlying condition and should be checked by a doctor when accompanied by other symptoms such as
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Unexplained weight loss
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Chest pain, palpitations, or breathlessness
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Headaches
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Excessive thirst or urination
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Significant mood changes
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Muscle weakness
It's always safer to verify with a doctor your feelings of tiredness and whether there may be something more serious going on in your body. Consider whether the fatigue you feel is disproportionate to your life demands and if sleep debt, nutrient deficiency, or lifestyle drain may have anything to do with it.
Can supplements help?
There's a difference between supplements that boost energy in healthy people and supplements that fix actual deficiency. Knowing which is which can help you get rid of your fatigue for good, with adequate professional advice from a medical practitioner of course.
Supplements may help support general energy levels as part of a balanced diet, particularly where dietary intake of key nutrients is low. For example, Iron is an important nutrient that contributes to normal energy levels; if you are concerned about your iron intake, speak with a healthcare professional.. However, be mindful that supplements may have side effects when addressing your nutritional deficiency (e.g. iron supplements may cause constipation).
How to get more energy for exercise
Prioritising your pre-workout nutrition can help you get the energy you need to train and exercise.
When it comes to intense exercise such as the training at the gym or running a marathon, here's a few tips to help you get more energy to deliver your best performance:
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Take a pre-workout half an hour before, or have a big meal two to three hours before exercise
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Prioritise carbohydrates so you have glucose readily available in your body to burn during exercise
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Including protein before training may help support your performance and recovery as part of a balanced nutrition plan.
Caffeine and energy
Caffeine is commonly used to support energy levels and may help reduce feelings of tiredness during daily activities and exercise. Its energising effects can benefit daily activities as well as physical activity and exercise. Many pre-workout supplements contain caffeine for this very purpose.
However, before taking a pre-workout, make sure you consider:
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Dosing: Pre-workouts usually indicate how much caffeine is in each serving - check this dosage and whether your body weight can handle it
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Tolerance: If you regularly consume caffeine, its energy-boosting effects may decline over time
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Timing relative to sleep: Caffeine shouldn't be taken too close to your bed time as it may cause sleep disruptions and inability to fall asleep
As covered above, feeling tired is a common and usually easily resolvable problem, yet it is important to not underestimate how it can affect your daily life. If you're feeling tired all the time, it might be a good idea to investigate potential causes and pay closer attention to your body before fatigue has lasting effects on your body and lifestyle.
