The 8 surprising reasons why you might be tired all the time

If you’re wondering why you’re constantly exhausted, it could be a sign of an undiagnosed health issue. From subtle nutrient deficiencies to underlying medical conditions, there are a wealth of hidden factors that could be quietly draining your energy – and they’re more widespread than you might think.

“Choline is one of those lesser-known nutrients that doesn’t get the spotlight it deserves – yet it plays a big role in brain health, mood regulation, energy levels and even how well your liver functions,” explains Healthspan nutritionist Rob Hobson. While our bodies can produce small amounts, it’s not nearly enough to meet our needs, so we rely heavily on what we eat.

“Eggs and meat are rich sources, which is why vegans and vegetarians are more vulnerable to falling short. That said, it is not just about animal foods – plant-based eaters can still get some from broccoli, kidney beans, peanuts and even mushrooms, though the levels are much lower and you’ll need more of these foods,” says Rob. “So if you’re feeling fatigued or low in energy, it might be time to look at your intake.”

Vitamin D – also known as “the sunshine vitamin” – plays an essential role in providing energy to all the cells in the body. If your levels are low, you may feel tired and run down all the time, making it difficult to get through your day-to-day activities. Around one-in-six adults in the UK is low in vitamin D, especially if you spend lots of time indoors. The sun’s rays are not strong enough for the body to produce sufficient amounts of it in winter, so the NHS advises us to take a 10 microgram supplement daily from October to March.

Try to get 15 to 20 minutes of sun exposure a day in summer (without sunscreen on small areas like arms or legs), then apply SPF if staying out longer.

Undiagnosed thyroid problems can lead to tiredness, weight gain and low mood – especially if your thyroid is under-active. “When your thyroid gland doesn’t produce enough hormones, the hypothyroidism that follows slows down your metabolism, which can leave you feeling tired and foggy headed,” says Irish GP Dr Gareth Patterson. Left untreated, the symptoms, which develop gradually, can worsen. The key is to get symptoms checked and have the right treatment to restore energy levels.

“Thyroid issues are easily diagnosed through a simple blood test which your GP can organise,” explains Dr Patterson. “Hypothyroidism is then treated with levothyroxine tablets to boost levels of thyroid hormone in the body.”

Studies show that caffeine can have a rebound effect and overstress the adrenal glands, leading to more exhaustion. Caffeine has its perks – it gives your morning a lift and is one of the most researched sports performance enhancers out there. But Rob warns: “There’s a tipping point. If you’re especially sensitive – around one-in-five – too much can bring on jitters, anxiety or sleep issues, which can feed into a cycle of fatigue.

“Caffeine can also raise levels of the stress hormone cortisol.” A sensible upper limit is around 400mg a day – which is roughly four cups of instant coffee or one to two strong shop-bought brews.”

Medicines have transformed our healthcare and are necessary for many people, but patients are often unaware of their impact on nutrition and how this can make them feel worse,” explains Dr Siobhan Brenna, a GP. “Nutrient depletion is rarely listed as a side effect and it’s hard to make the connection because it can happen slowly over time.”

Registered pharmacist, Gurdeep Nanra, adds: “Drug-nutrient interactions are often overlooked in routine prescribing. While dosage and side effects are monitored, the long-term impact of certain medications on nutrient levels is rarely discussed. Over time, deficiencies in vitamin B12, magnesium, CoQ10, and other essential nutrients may affect overall health.”

Visit your local health food stores to find a copy of Medication + Nutrition, a concise, evidence-based guide. You can also visit viridian-nutrition.com and chat to your GP and pharmacist if you have any concerns, and ask for a medication review.

“Low iron can lead to anaemia, which affects your body’s ability to carry oxygen efficiently, leaving you feeling constantly drained,” warns Dr Patterson. Older adults are especially vulnerable if they have a poor diet or other medical conditions, as are women having periods because of the monthly blood loss. “Your GP can order a full blood count test to check your iron levels. If levels are low, you may need an iron supplement, but diet is also important,” says Dr Patterson.

The best food source for iron is red meat, especially liver, but vegetarians can get some iron from leafy greens like spinach and broccoli. If you’re not eating enough, try a supplement such as Healthspan Ironcare (120, £8.99, healthspan.co.uk). If you have anaemia, avoid tea, coffee or wine within two hours of eating iron-rich meals or taking tablets, as they can interfere with its absorption.

Research published in the Archives of Internal Medicine found that the more severe your allergic symptoms are, the more impaired your sleep will be. Hay fever sends your immune system into overdrive, which can trigger chronic inflammation and fatigue. It can also interfere with your breathing, cause snoring, and keep you up at night.

As well as the usual medication, some simple tips can also help reduce symptoms: including wearing wraparound sunglasses, which will cut the amount of pollen landing in your eyes; having a shower and changing your clothes when you get home; keeping your bedroom window closed during the day and ensuring that you don’t dry clothes outdoors on high pollen count days. Saltwater nasal rinses are effective at cleaning out pollen and excessive phlegm from the nose.

“Even a small drop in hydration can make you feel tired and foggy headed,” says Phil Beard, Nutritionist at ethical supplement brand Viridian Nutrition. It affects blood flow to the brain and muscles, which impacts both energy and concentration.

“If you’re sweating heavily through exercise or heat exposure, consider adding a natural electrolyte such as Viridian’s Electrolyte Fix Liquid to water, (100ml, £14.25, viridian-nutrition.com). “It helps replenish minerals like sodium, potassium and magnesium lost through sweat and supports fluid balance,” says Phil.

Electrolyte supplements aren’t for everyday sipping and shouldn’t be used unless you’re losing fluids through exercise, heat, or illness. Too much sodium or potassium can be harmful, especially if you have high blood pressure, kidney issues, or other health conditions. Follow label directions and check with a healthcare professional if unsure. Aim for six to eight glasses of fluid daily, more if you’re active or it’s hot. You should be going to the loo every two to four hours, and your urine should be pale yellow.