The average Briton spends more than seven-and-a-half years of their lifetime feeling tired, a study suggests.
Each day, adults said they spent two hours and 56 minutes feeling drained and low in energy – more than twenty hours each week.
This amounts to almost four days of each month or six weeks of every year during which we feel fatigued.
It also emerged 43 per cent have occasions where they feel tired from the moment they wake up, to the moment they go to sleep.
Dr Sarah Brewer, a medical nutritionist working on behalf of Healthspan, which commissioned the research as the company unveiled a new vitamin D spray said: “It’s not widely known that a lack of vitamin D is associated with fatigue and exhaustion.
"Lack of vitamin D may contribute to the energy slump that many people experience towards the end of winter when our vitamin D levels are at their lowest.
"Correcting a vitamin D deficiency can significantly improve fatigue in otherwise healthy people with vitamin D deficiency.”
Sleepless nights are the most common reason for exhaustion in the UK, with 54 per cent of the population blaming them for tiredness.
Early mornings account for more than a third of the nation’s sleepiness, and another third blame the winter’s dark mornings and early evenings.
Yo-yo dieting is another reason for feeling tired along with bad weather, long working hours and even a poor diet.
Unsurprisingly, Monday was found to be the day of the week when we feel the lowest on energy, followed by a midweek low on Wednesday.
And most people hit an energy slump just after lunchtime, with our last reserves of puff running out at 1:59pm.
More than half the population struggle so much with tiredness, they often spend their weekends recovering from the working week instead of going out socialising or partying.
The study, carried out via OnePoll.com, found 18 per cent have used a day of their annual leave just because they were too tired to carry on, while 14 per cent have called in sick to catch up on much needed sleep.
A further 58 per cent have cancelled nights out with friends due to tiredness, and 30 per cent have skipped plans to exercise.
To fend off tiredness, four in 10 Brits turn to the caffeinated joy of tea or coffee or go for a walk in the fresh air.
And 44 per cent of respondents will resolve to have an early night to avoid these feelings of tiredness happening again the next day.
But almost four in 10 have turned to supplements to try and boost their energy, with more than one in 10 saying they have been diagnosed with low levels of vitamin D.
Top ten reasons for feeling tired:
1. A sleepless night
2. Having to get up early
3. A late night
4. Dark mornings and evenings
5. Bad weather
6. Too much or not enough exercise
7. Working long hours
8. Busy work schedules
9. A poor diet
10. A large workload
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