Why you’re so tired all the time – it may not be lack of sleep

From too much exercise to not enough vitamin D, the experts tell us why we’re feeling sluggish, and how to fix it.

GPs see many patients who are very tired at this time of year. Picture: Getty Images

Feeling exhausted despite that early night? Tiredness is a sure sign your body isn’t getting what it needs, but it doesn’t necessarily mean you are not sleeping enough. Last week researchers for US space agency NASA suggested we routinely underestimate how tired women are feeling and overestimate the same levels of tiredness in men, but the truth is most of us feel fatigued during the dark days of January and February.

Winter viruses certainly play their role in leaving us low on energy. “GPs will commonly see a lot of patients with tiredness at this time of year and there is an endless list of possible underlying causes,” says Dr Dan Baumgardt, a GP and senior lecturer in the School of Physiology, Pharmacology and Neuroscience at the University of Bristol.

“A preceding viral illness, such as a heavy cold or flu, might be to blame and patients can feel tired and run-down for quite a long a period of time after the viral symptoms have resolved.”

But there are many other reasons that you might be feeling so low on energy. Here’s what our experts advise.

Are you eating enough?

If you are on a January health kick and have cut down on your food intake or started a diet, it could be to blame for your waves of fatigue. If you drastically reduce your calorie intake, your body responds by attempting to conserve energy, which means it will burn fat stores but also can lead to fatigue and a lack of motivation.

“A persistent grumbling stomach is a sure sign your tiredness is linked to your reduced energy intake,” says Rhiannon Lambert, a registered nutritionist and the author of The Science of Nutrition. “Rather than reducing calories to a minimum, focus on nutritious foods that will sustain your energy levels, prevent energy dips and fill you up so that you eat less overall, such as vegetables, whole grains, lean proteins and healthy fats.”

Drastically cutting carbs has been shown in studies at the University of Queensland and elsewhere to result in fatigue for some people. “Do cut down on refined carbs, but fill up on whole grains such as brown rice, oats, rye and quinoa, which provide a longer-lasting energy boost,” Lambert says.

Are you spending too much time sitting down?

We all know too much sitting is bad for our health – perhaps counterintuitively too much time off our feet can also make us more tired. Adding short activity breaks could stop the lethargy that sitting induces and three minutes of gentle exercise could be all it takes.

A study published in the BMJ reported that constant sitting resulted in a lower heart rate and a reduction in chemicals that help to control the sleep/wake cycle, both of which cause feelings of tiredness.

The Australian authors of the study compared the effects of five hours’ continuous sitting with the effects of breaking up the same duration of prolonged sitting with three-minute bouts of light-intensity walking every half an hour on overweight participants who complained of feeling tired and low on energy. Results showed the short walking breaks to be “an effective fatigue countermeasure” that significantly reduced tiredness scores and increased heart rate, which helped to deliver supplies of glucose to the brain to raise energy levels.

Are you drinking too much coffee?

Caffeine has a stimulatory effect so provides an instant energy boost, but that can backfire. “Caffeine affects the body’s chemical adenosine receptors, which normally promote sleep and suppress arousal,” says Dr Linia Patel, a researcher in the department of clinical sciences and community health at the Universita degli Studi di Milano in Italy and a spokeswoman for the British Dietetic Association. “When you consume it, it overrides the receptors in the brain to make you feel more alert.”

But relying too heavily on strong tea or coffee to keep you going can cause “rebound drowsiness” as the stimulatory effects wear off, Patel says. “Over time you will find that it takes more caffeine to fight tiredness,” she adds. And reaching for an extra brew because you feel weary could make matters worse.

“High intakes of caffeine are known to impact sleep duration and quality, which could also make you more tired the next day,” Patel says. A study at Cardiff University found that while caffeinated drinks boosted alertness temporarily, people who consumed them often felt more tired the following morning. Stick to no more than four cups a day, Patel says, and avoid caffeine from early evening onwards.

Do you need to take a vitamin D supplement?

About 1 in 6 adults and almost 1 in 5 children in the UK have vitamin D levels lower than government recommendations, according to official statistics. Although some vitamin D can be found in dairy products, oily fish, cod liver oil, milk and eggs, natural food sources are scarce, yet many people don’t follow official advice to consider taking a 10mcg supplement during the darker months of late autumn, winter and spring to prevent deficiency.

“A survey commissioned by the British Nutrition Foundation found that almost half – 49 per cent – of UK adults weren’t aware of the advice to take a winter supplement,” Lambert says. “And 39 per cent said they never take vitamin D supplements at all.”

This could have an effect on our energy levels. Researchers at the University of Florida College of Medicine suggested vitamin D deficiency should be considered for people with “unexplained fatigue” and others have suggested supplementation could “significantly improve fatigue” if a vitamin D deficiency is diagnosed.

“If you have a deficiency you need to consult a registered nutritionist or dietician who will prescribe appropriate dosages,” Lambert says.

Are you stressed? (It could be affecting your hormones)

Stress is one of the biggest underlying causes of unexplained tiredness and not just because it affects our ability to sleep well. Baumgardt says that stress is linked to many conditions that affect almost every system in the body. “Our body’s stress responses drive up nervous activity and hormones that impact many different organs – heart, lungs, the brain – that then leave us feeling very fatigued,” he says. “Sometimes in managing stress, you can alleviate the tiredness.”

Each person responds differently to stress and also to stress-reducing activities, so it is important to find something that helps you to relax. Try to remove yourself from the source of stress or a stressful environment with anything from t’ai chi and yoga to running or knitting.

Is your consumption of UPFs still too high?

Last year a study in the BMJ warned that diets high in ultra-processed foods (UPFs) – breakfast cereals, fizzy drinks, ready meals and energy bars – can harm many elements of our health. Rob Hobson, nutritionist and author of Unprocess Your Family Life, says too many UPFs will undoubtedly leave you feeling fatigued.

“These foods are often low in essential nutrients including iron, magnesium and the B vitamins that play key roles in energy metabolism and oxygen transport,” he says. “Emerging evidence suggests that some additives in ready-made and processed foods, such as emulsifiers, may adversely impact the gut microbiome and gut lining, producing changes that influence nutrient absorption and energy balance.”

Evening drinking saps energy. Picture: Getty Images

Are you drinking wine too close to bedtime?

A glass or two of wine to help you nod off at night could backfire by making you feel more tired the next day. This is because alcohol disrupts your sleep cycle, reducing the quality of your sleep so that you end up over-tired the next day, says Kevin Morgan, emeritus professor of psychology at Loughborough University’s Clinical Sleep Research Unit.

“Even one or two drinks at night will saturate your system with alcohol so that you might fall asleep more quickly but after about four hours find you wake up and not feel good,” Morgan says. “The anti-diuretic hormones that regulate fluid balance and are pumped out at night decrease from midlife, so our ability to retain fluid falls and you will probably find you are up and down to the toilet during the night.”

Last year a study in the journal Sleep showed that alcohol reduces the amount of time we spend in the rapid eye movement (REM) stage of sleep, an important restorative stage.

Are you spending too much time indoors?

Yes, it’s cold and grey outdoors, but a few minutes outside could boost your energy levels. Even on a dull day, natural daylight is more potent than artificial light and has the power to put a spring in our step.

The amount of natural daylight that enters our eyes is monitored by various parts of the brain including the pineal gland and the hypothalamus, which manufacture and release serotonin, a neurotransmitter that, among other roles, helps to keeps us energised.

“Several studies, including one that involved 85,000 people in Nature journal, have shown that regular exposure to natural daylight has very important beneficial effects on brain and mood,” says Jennifer Wild, consultant clinical psychologist and associate professor at the University of Oxford. “If you can get away from your desk and outside for five minutes both morning and evening it could have a profound effect on your mood and energy levels at this time of year.”

Is your vegan diet affecting your energy?

A plant-based diet can leave you feeling energised but only if it is carefully balanced. For many there’s a risk of missing out on important nutrients that could leave you feeling flat and fatigued. One of these is vitamin B12, which is found predominantly in animal produce including meat, fish, dairy and eggs. If you eat these you will probably be getting the 1.5mcg a day of the vitamin that health chiefs recommend for adults. If not, you will need to take a supplement to make up the shortfall.

Iron from meat is easier to absorb than that from plant-based food. Picture: Getty Images

“The B vitamins play an important role in helping our bodies release energy from the foods we eat,” Lambert says. “And a B12 deficiency can impair energy production and lead to anaemia, resulting in excessive fatigue.”

A lack of iron, which enables our red blood cells to ferry oxygen around the body, is also a risk. “Too little iron in the diet can lead to iron-deficiency anaemia, symptoms of which include feeling tired, breathless or exhausted,” Lambert says.

The NHS says healthy intakes for men of all ages and women aged 50 to 64 is 8.7mg of iron a day and for women aged 19 to 50 it is 14.8mg a day. Haem iron, present in offal, red meat, eggs, fish and seafood, is more easily absorbed by the body than the non-haem iron from plant sources such as beans, lentils, green vegetables, hazelnuts, dried fruit, olives, wholegrains, pumpkin seeds and tofu, but consuming as wide a variety of these foods as possible should meet your needs, Lambert says.

Are you getting enough fibre?

Government guidelines recommend consuming 30g of dietary fibre, found in plant-based foods including fruits, vegetables, legumes, wholegrains, nuts, and seeds, per day as part of a healthy, balanced diet, but figures from the British Dietetic Association show that the average intake is 18g daily, only 60 per cent of the target.

“Fibre plays a key role in promoting healthy bowel movements, so not getting enough can leave you feeling sluggish as your digestive system slows down,” Lambert says. “Fibre also helps to stabilise blood sugar by slowing the absorption of glucose into the bloodstream and if you don’t get enough of it you might experience frequent energy crashes or ongoing fatigue.” To increase your intake she suggests adding fibre to every meal by adding beans or lentils to soups and stews, sprinkling nuts or seeds onto salads or porridge, and choosing wholegrain options such as brown rice or wholemeal bread instead of refined alternatives whenever possible.

Do you need a break from exercise?

Working out will get you fitter but there is a tipping point at which too much intense exercise starts to leave us tired and demotivated. “We have a lot going on in our lives and balancing other commitments in life such as work and caring responsibilities with exercise routines can create physical and psychological burdens that cause us to fatigue,” says Dr Daniel Brayson, a lecturer in life sciences at the University of Westminster.

“If you work out hard on five or more days a week, then you probably need to factor in a de-load week every 4-6 weeks.” A de-load week means a 50 per cent reduction in exercise volume - the time spent working out – and a 20 per cent reduction in exercise intensity, reducing the pace of a run or weights lifted.

“Unless you are completely exhausted or wiped out, doing nothing if you are used to exercising is akin to keeping a wild animal in a cage and can cause stress, anxiety and restlessness,” Brayson says. “So keep things ticking over but allow your body time to repair and recuperate so that you feel less tired when you return to your regular pattern.”

Is your medication making you tired?

A long list of medications including some antidepressants, statins and antihistamines can make you feel tired. “Patients starting on a new medication could find that they develop tiredness after starting it, or sometimes it can hit after they’ve after taking it for a longer period,” Baumgardt says. “It might be that it resolves by itself, but it would be advisable to see your GP if it persists to explore whether there is an alternative cause or what options for different medications are available.”

Are you remembering to drink enough water? (It’s not just an issue when it’s hot)

Most of us think of summer as the time we are most prone to the energy-zapping effects of dehydration, but in winter we tend to drink less because we feel less thirsty. That, combined with the dry air of centrally heated buildings, can leave us in fluid deficit, with symptoms of headache, impaired performance and fatigue.

“Not drinking enough at this time of year is one of the main reasons why people feel tired and sluggish,” Patel says. “Our circulatory and other systems have to work under immense strain when the body lacks fluids and this can cause mental and physical fatigue.”

So how much fluid do we need? Precise levels vary according to your body size, activity levels and lifestyle, but government advice is to aim for 1.2 litres in everyday conditions. Check the colour of your urine to make sure it is a pale straw colour, a sign you are well hydrated.

Should you see a doctor?

If you have persistent tiredness, lasting over several months, it is wise to see your GP, who may suggest a blood and urine test to check for underlying medical causes. “These tests might include a blood count to check iron and vitamin levels to see if a patient is anaemic, glucose testing for diabetes or thyroid function tests to see if a patient has an over or underactive thyroid gland,” Baumgardt says.

“Coeliac disease, a condition where the immune system attacks its own tissues when you eat gluten, can also present as tiredness, sometimes instead of gastrointestinal symptoms, and this can also be identified through a blood test.”

Depression, anxiety and other psychological conditions can also present as tiredness. “Most, if not indeed all, clinical conditions can generate a form of fatigue or lethargy, so a GP will discuss these with you,” he adds.

The Times