You're tired throughout the day and use cups of coffee to keep you propped up - does that sound familiar?

If so, you're not alone. A recent survey carried out by market analysts Mintel reveal that one in three of us admit we’re permanently worn out because of the pace of modern life.

GPs have also revealed that around 10% of us visit solely to find out about unexplained tiredness.

While there is much left to explain about our relationship with sleep, a few experts have given their tips on what they think might be the less obvious causes of fatigue:

You’re not exercising enough

It might be the last thing you feel like, but avoiding exercise because you're tired actually makes you feel worse.

In a University of Georgia study, sedentary but otherwise healthy adults who began exercising lightly three days a week for just 20 minutes reported feeling less fatigued and more energized after six weeks.

This is because regular exercise makes your heart and lungs work more efficiently, delivering oxygen and vital nutrients around the body.

Reboot your energy: Next time you’re tempted to flop on the sofa, force yourself up for a brisk 10-minute walk – you’ll feel more alert for it.

Your coffee addiction is sapping your energy

Although we think of caffeine as a pick-me-up, it actually makes us feel more tired once the initial surge wears off.

Director of The Lifestyle Medicine Clinic Dr Chidi Ngwaba said: “This is because our brain chemistry doesn’t like being interfered with by stimulants, so it releases chemicals to dampen down the alert response.”

Coffee is also a serious disrupter, with one study in the Journal of Clinical Sleep Medicine revealing that drinking it even six hours prior to bedtime meant a worse night's sleep.

Reboot your energy: Avoiding caffeine will increase energy levels in the long run – but cut down gradually, cup by cup, to avoid headaches and irritability.

You have an iron deficiency

Figures show that around a third of women are low in iron often due to heavy periods.

Some have low enough iron levels to be anaemic. If you pull down your bottom eyelids and the inner rim looks pale rather than pink, it’s an indicator.

Reboot your energy: A blood test will pick up any iron problems and you’ll be prescribed tablets to boost levels.

You’re missing out on vital B-vitamins

Nutritionist Rob Hobson said: “We all have increasingly busy lives, so it’s essential to provide the body with enough calories and vitamins to get through the day.

“B vitamins are particularly vital as they’re required by the body to convert the food you eat into energy.”

Reboot your energy: Get your healthy dose of this group of vitamins in lean proteins such as oily fish and turkey as well as grains like brown rice, barley and oats.

You’re overdosing on sugar

Nutritionist Linda Foster said: “What many people don’t realise is that they can actually be made more tired by the very foods supposed to give them energy.

“Sugary energy drinks and snack foods such as biscuits, chocolate and crisps cause sharp spikes then dips in blood sugar that can leave you flagging, irritable and desperate for a mid-afternoon nap.”

Reboot your energy: Swap to low-sugar foods – and this includes avoiding white carbs such as bread and pasta which quickly convert to sugar in the body.

Opt for granary bread and wholemeal pasta as they release energy more slowly.

You are dehydrated

Losing as little as 2% of your body’s normal water content can take its toll on your energy levels.

It’s surprisingly easy to become dehydrated, especially as we tend to lose our thirst reflex as we get older.

Working in an air-conditioned office, going for a long walk or simply forgetting to drink regularly can quickly lead to depleted fluid levels.

This causes blood pressure to drop and means not enough blood gets to the brain or muscles.

This can cause headaches, fatigue and loss of concentration.

Reboot your energy: Try to drink every two hours. If you’re not peeing regularly or your urine is very dark, it’s a sign you need to drink more.

You’re skimping on protein

Surviving on fruit and salad might feel worthy, but avoiding protein in the form of meat, dairy and nuts will leave you exhausted, as it’s a vital energy giver.

They also release energy much more slowly than sugary snacks and so will keep you fuller for longer.

Reboot your energy: Snack on protein to keep energy levels stable. Eating a minimum of a palm-sized amount of protein with meals and eating seeds and nuts or nut butters can prevent tiredness.

Good protein sources are meat, fish, cheese, tofu, beans, lentils, yogurt, nuts and seeds.

Your thyroid is sluggish

Having an underactive thyroid – which means it’s not making enough of the hormone thyroxine – is a surprisingly common cause of unexplained fatigue, especially in middle-aged women.

Other symptoms of a thyroid condition include excessive thirst, weight gain and feeling cold.

Reboot your energy: See your GP who can give you a blood test.

If an underactive thyroid is diagnosed, a simple once-a-day tablet can correct the problem – and most people get their normal energy levels back soon after starting treatment.

You’re storing up stress

Naturopath Martin Budd said: “While a little stress helps to keep us on our toes, long-term stress – for example from work or relationship problems – can exhaust the body, as well as being emotionally draining.”

Reboot your energy: “It’s our response to stress that’s much more damaging to our health than the stress itself,” says Dr Chidi.

“So by learning how to diffuse stressful situations, we can reduce their impact.”

When stress strikes, instead of going frantic to fix things, try to slow down and take a break instead.

Call a friend, walk the dog or do some yoga.