Why Am I Always Tired? Common Causes of Fatigue and What Helps

Constantly tired, even when you think you've slept enough? Fatigue is one of the most common reasons people see a health professional, and it has many possible causes.⁵ As a dietitian, here's what I look at first and what can help.

Are you getting enough good-quality sleep?

Poor sleep is the most common culprit. Australian guidelines recommend adults get 7–9 hours of good-quality sleep, with consistent bed and wake-up times.⁶ Stress, working late, screens and even overtraining can all get in the way.

Sleep debt also adds up. If you've had several short nights, one good night may not be enough to feel normal again. A few early nights in a row can help you catch up.

Simple ways to sleep better:

• Cut caffeine after midday. In a trial, a moderate dose of caffeine taken even 6 hours before bed still disrupted sleep.³
• Keep your bedroom dark, quiet and cool, with good airflow. If your pet keeps waking you, find it another bed.
• Keep work and scrolling out of bed. Use your bed for sleep and sex only.
• Stop drinking fluids about an hour before bed and go to the toilet just before sleep, to cut down night-time trips.

Could a health condition be making you tired?

Yes. Fatigue is a symptom of many conditions, so it's worth getting checked if it doesn't improve with better sleep.

• Sleep apnoea: breathing repeatedly stops and starts during sleep. It's estimated to affect almost 1 billion people aged 30–69 worldwide, and many don't know they have it.² Loud snoring, gasping or waking unrefreshed are common signs.
• Anaemia: iron deficiency is one of the most common causes, but not the only one.
• Thyroid problems, diabetes and heart disease.
• Depression and anxiety, which often affect sleep and energy.
• Coeliac disease and other gut conditions that affect how you absorb nutrients.
• Chronic fatigue syndrome (myalgic encephalomyelitis).
• Medicines, as a side effect.⁵

What deficiency causes tiredness?

Low iron is the best-known one. It can cause tiredness even before it's low enough to cause anaemia. A meta-analysis of trials found iron supplements reduced fatigue in adults who were iron deficient but not anaemic.¹ People with heavy periods, vegans and vegetarians, frequent blood donors and endurance athletes are at higher risk.

Vitamin B12 is another to check, especially if you're vegan, as it's found mainly in animal foods. Vitamin D is often tested too.

What should you eat for more energy?

Food is fuel, so regular meals built around wholefoods help keep your energy steady:

• Don't skip meals. Long gaps can leave you flat and more likely to reach for sugary snacks.
• Include iron-rich foods, like lean red meat, chicken, fish, legumes, tofu and leafy greens. Pair plant sources with vitamin C (such as citrus or capsicum) to help absorption.
• Choose wholegrains and fibre-rich carbohydrates over refined, highly processed foods.
• Add protein to each meal, such as eggs, dairy, meat, fish, legumes or nuts, to help keep you full.
• Drink enough water. Even mild dehydration can leave you feeling flat.

Does exercise help with tiredness?

Yes, for most people. A meta-analysis found regular exercise increased feelings of energy and reduced fatigue.⁴ If you're very tired, start gently with walking, swimming or yoga and build up. If you train hard, make sure you're also resting and eating enough, as overtraining can make fatigue worse.

If stress is part of the picture, relaxation techniques such as meditation or breathing exercises can help you wind down before bed.

Frequently asked questions

Why am I always tired even after sleeping?

Your sleep may be poor quality, you may be catching up on sleep debt, or a condition like sleep apnoea, low iron or depression may be involved. See your doctor if it lasts for weeks.

What deficiency causes tiredness?

Low iron is the most common, even before it causes anaemia. Low vitamin B12 can also cause fatigue, especially in vegans.

Should I take supplements for tiredness?

Only if a test shows you're low in something. Too much iron can be harmful, and "energy" supplements don't help if you're not deficient.

Can caffeine make you more tired?

It can, by disrupting sleep. Caffeine taken even 6 hours before bed affected sleep in one trial, so try to stop after midday.

Does exercise help with fatigue?

For most people, yes. Regular exercise is linked with more energy and less fatigue. Start gently if you're very tired.

References

Research (PubMed)

1. Houston BL, Hurrie D, Graham J, et al. Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials. BMJ Open. 2018;8(4):e019240. PubMed 29626044
2. Benjafield AV, Ayas NT, Eastwood PR, et al. Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis. Lancet Respir Med. 2019;7(8):687–698. PubMed 31300334
3. Drake C, Roehrs T, Shambroom J, Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 2013;9(11):1195–1200. PubMed 24235903
4. Puetz TW, O'Connor PJ, Dishman RK. Effects of chronic exercise on feelings of energy and fatigue: a quantitative synthesis. Psychol Bull. 2006;132(6):866–876. PubMed 17073524

Australian guidelines

5. healthdirect Australia. Fatigue. View source
6. Australian Government Department of Health, Disability and Ageing. Physical activity and exercise guidelines: recommendations for adults (18 to 64 years). View source

This article is general information and isn't a substitute for personalised advice. Speak to your practitioner about your situation.