Fight the flagging: Eight simple science-backed ways to combat tiredness

But if you are just flagging for no apparent reason, then weigh up what could be contributing to your fatigue, in terms of your diet, lifestyle and exercise habits.

Are you moving enough?

Too much sitting is bad for our health, and, counterintuitively, can also make us more tired. Short activity breaks could stop the fatigue cycle and three minutes of gentle exercise could be all it takes. 

A study published in the British Medical Journal compared five hours of continuous sitting with the same duration broken up by three-minute bouts of light-intensity walking every half-an-hour.

The participants were overweight and 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.

Are you taking enough fluids?

Most of us think of summer as the time we are most prone to dehydration, which saps energy, but in winter we tend to drink less because we feel less thirsty.

That, combined with the dry indoor air of centrally heated buildings, can leave us ‘hypohydrated’, or in fluid deficit.

“Not drinking enough at this time of year is one of the main reasons why people feel tired and sluggish,” says Dr Linia Patel, a researcher in the Department of Clinical Sciences and Community Health at the Università degli Studi di Milano in Italy.

“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 expert advice is to aim for 1.2l in everyday conditions. Check the colour of your urine during the day to ensure it is a pale straw colour, a sign you are well hydrated.

Are you drinking in the evening?

A glass or two of wine to help you nod off at night could make you feel more tired the next day. 

Alcohol disrupts the sleep cycle, reducing the quality of your sleep, so that you end up over-tired the next day. Even one or two drinks at night will saturate your system with alcohol, so that you may fall asleep more quickly, but wake during the night. 

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

This will also impact how tired you feel the next day.

Are you spending too much time indoors?

Yes, we know it’s cold and wet outdoors, but a few minutes outside could boost your energy. 

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 entering 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 keeps us energised. 

A Nature journal study involving 85,000 people showed that regular exposure to natural daylight has important beneficial effects on the brain and mood. 

Spending even five minutes outside each morning and evening could significantly improve your mood and energy levels at this time of year.

Do you take a vitamin D supplement?

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 HSE advice to take a 15mcg vitamin-D supplement from Halloween (October 31) to St Patrick’s Day (March 17); or to take it all year round if you have darker skin tone, reduced sun exposure, or are pregnant.

In a 2020 study published in the Irish Medical Journal, Dr Daniel McCartney, of Technological University Dublin, and his medical colleagues, suggested that, due to high deficiency rates, people in Ireland should prioritise vitamin-D supplementation, aiming for a higher intake of 20-50mg per day. 

“It is not possible to get adequate amounts of vitamin D from food or sunshine at this time of year,” McCartney says. “And there is a high prevalence of vitamin-D deficiency in this country, with adults of all ages at risk.”

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.

Have you switched to a plant-based diet?

A plant-based diet should leave you feeling energised, if it is carefully balanced, but there’s a risk you might miss out on important nutrients.

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 likely get the 1.5mg of vitamin that health experts recommend for adults daily. If not, you will need to take a supplement.

The B vitamins help our bodies release energy from the foods we eat, and it follows that 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.

The HSE says healthy intakes for men of all ages and for women aged 50 to 64 are 8.7mg of iron a day; while women aged 19 to 50 need 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, leafy green veg, pumpkin seeds, tofu and dried apricots, but consuming a a variety of these foods should meet your needs.

Are you getting enough fibre?

Dietitians 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. 

However, according to research, the average intake is 18g daily, which is only 60% of the target.

Fibre is important for promoting healthy bowel movements and not enough fibre can leave you feeling sluggish, as your digestive system slows down.

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.

Dietitian Orla Walsh says we can get enough fibre “by eating plenty of wholemeal bread, fruit and vegetables, oats and wholegrains, and nuts, seeds and pulses on a regular basis”.

Are you drinking too much coffee?

There’s little doubt that a cup of coffee, or any other caffeinated drink, will raise you from a mid-morning or afternoon slump. 

“Caffeine affects the body chemical adenosine, which normally promotes sleep and suppresses arousal,” says Patel.

“When you consume it, it overrides the receptors in the brain that detect adenosine and makes you more alert.”

However, relying heavily on strong tea or coffee to keep you going can cause “rebound drowsiness” as the stimulatory effects wear off.