is this the surprise reason you’re always tired?

aS A mother to three children under 12, I expect to feel totally exhausted at the end of the day. What I didn’t realise, though, was that a lack of an essential vitamin could be to blame for my paltry physical stamina.

A while ago, during a series of blood tests for some imaginary ailment (no doubt tiredness related), my levels of vitamin D — essential for the absorption of calcium — were found to be very low.

The doctor didn’t seem to think this was significant but, as my mother, aged 78, has osteoporosis, I thought perhaps I should take a supplement. The condition, where bones become brittle, has been linked to a lack of vitamin D, although there are strong genetic factors as well.

I’d probably have thought little more of it, but last month, I read about intriguing research which found boosting vitamin D intake can raise energy levels and lower blood pressure.

In the study, by a medical team in Edinburgh, volunteers were asked to cycle for 20 minutes. They were then given either a placebo or vitamin D and, two weeks later, were asked to cycle for 20 minutes again.

Those who’d taken the vitamin D were able to ‘cycle longer with less effort’ and showed diminished levels of the stress hormone cortisol, which can also cause raised blood pressure as it narrows blood vessels.

Vitamin D deficiency is a peculiarly contemporary phenomenon. The most efficient way of absorbing what is an essential vitamin is through sunlight directly on the skin.

But, ironically, in our bid to avoid sun damage — a contributory cause of both skin cancer and premature ageing — many of us just don’t get enough.

Indeed, some ten million people in the UK are estimated to have low levels of Vitamin D.

tHOUGH the Scottish study only had 13 participants, its lead author, Dr Emad Al-Dujaili, of Queen Margaret University, is convinced of its importance. ‘Vitamin D deficiency is a silent syndrome linked to insulin resistance, diabetes, rheumatoid arthritis, and a higher risk for certain cancers,’ he says.

It all sounds so convincing I decide to conduct my own experiment to see if boosting my vitamin D levels would have a similar effect. first, I arrange for blood tests through online service Medichecks. My baseline reading for vitamin D comes back as 53 nmol/L, which is just within the ‘normal’ range this time.

The truth is, experts don’t agree on where the optimal range, or even ‘normal’, is, though 25 is considered severely deficient. Nutritionist Dr Marilyn Glenville (marilynglenville.com) says: ‘Some laboratories define more than 75 as normal and 80 to 100 as optimal.’

She, too, believes Vitamin D deficiency is one of the health stories of our age. ‘Research shows vitamin D can be antiinflammatory and that, aside from osteoporosis, its levels affect cardio health, type 2 diabetes, breast cancer, joint pains, allergies, fertility and immune function,’ she says.

‘The trouble is, we have so taken on the skin cancer message — plus sunscreen is in women’s skin creams, so we tend to be worse off than men — that we are even seeing the return of rickets.’ Rickets is childhood bone malformation caused by a lack of vitamin D and cereals were fortified to try to see it off.

My blood tests also record a midrange level of cortisol, the fight or flight ‘stress’ hormone, again implicated in inflammation. My blood pressure, meanwhile, is fine.

The next step in my experiment is the bike test, which I do in my gym. I manage 10.1km in 20 minutes and feel pretty tired when I come off. Then, for the next two weeks, I take a daily vitamin D supplement with food. Vitamin D3 is the best sort to raise vitamin D levels. It’s important to get the right amount so do consult a doctor or nutritionist. Too much vitamin D can be toxic so, as I am under eight stone, I go for 1000 iu which is the maximum the NHS advises people to take without specific medical advice; that will still give me twice the recommended daily amount.

A few days in, I begin to think — imagine? — I feel perkier in the mornings and less manic at bedtime. Ten days in, and I even have enough energy to go for a short run, much to the children’s amazement. By the end of the two weeks, I’m not exactly bouncing out of bed but I do feel more focused and somehow, stron-ger, like the voltage has been turned up.

The results of new blood tests show my vitamin D levels have risen and although my resting heart rate is the same, my blood pressure has gone down slightly and so have my cortisol levels. The moment of truth, though, is on the bike. I cycle again for 20 minutes and this time I cycle 11km — a boost of 0.9km — and I could easily have carried on.

Grand claims are made for Vitamin D these days, but I will say this: I am going to carry on taking these supplements whole-heartedly because they really do make me feel better. And that is pure, unadulterated sunshine.

FIRST, some bad news: most people will already have given up their New Year’s resolutions and fallen back into their old ways by now. If that’s not you, give yourself a smug pat on the back.

for the rest of us, if the prospect of another 11 months in the same tedious set of daily routines fills you with dread, you need a new book based on the classic comedy, Groundhog Day.

The 1993 film about a TV weatherman (played by Bill Murray) stuck in one endlessly repeating day has become a modern phenomenon, with many doctors admitting to prescribing the DVD rather than pills to their depressed patients.

There’s something about the way Murray’s character Phil Connors battles with the tedium of living the same 24 hours over and over again, finally escaping through kindness, selflessness and learning to live each moment to the full, which many people find deeply inspiring.

Now an exciting new book by Paul Hannam, a British personal development expert and Oxford University lecturer, claims to harness the power of what the author calls the ‘Groundhog Day Condition’ to guide people out of the work-sleep-work rut and change their lives for the better.

Hannam says so many of us wake up to the same old pattern, day after day, living in a continuous state of fretting. Here, he explains how you can break out of your Groundhog Day rut once and for all.

CHOOSE TO BE HAPPY

MOST of us take life for granted. We live in rigidly structured routines, working endlessly towards some everchanging future goal (perhaps a weekend place in the Cotswolds, an Audi, a three-week summer holiday, a cosy retirement . . .) But does this really make us happy? Most of us end up secretly dissatisfied and envious of our friends’ holidays, houses, cars and lifestyles, which makes it very hard to be content.

So try an experiment: make happiness your top priority and commit to choosing happiness over wealth, power, status, approval, control and security.

Ditch those grand plans and make small, incremental changes instead, with one aim: to improve the quality of your life, one minute at a time. So instead of setting goals for next year or even for next week, consider setting a goal for the next minute, and make that goal to be happy right now.

If you can find a way to be just as happy in heavy traffic on a damp Monday morning as you are with your friends in the pub on a friday evening, you will open the door to enjoying every moment of your life.

BIN YOUR BUCKET LIST

TO BE happy now and for the rest of your life, you need to remove the classic blocks. You know the ones: ‘I will be happy when I get that pay rise...when I’ve got a washboard stomach . . . when I’ve climbed Mount Kilimanjaro.’

The best way is to write a list of simple pleasures that make you happy and cost little or nothing: a deep bubble bath; a tight hug; crawling under a fluffy duvet at the end of a long day; completing a difficult crossword; the smell of fresh coffee or woodsmoke; a great book; watering the plants on a summer’s evening…

This simple exercise illustrates that a perfect life could already be well within your grasp. It shows that perhaps you don’t need more possessions, money or power as much as you need a little more awareness.

Why worry about earning the money to pay for exotic holidays when, for no cost at all, you can boost the quality of your non-holiday moments right here, right now?

So ditch that bucket list and shift your focus from seeking new experiences to improving the quality of your life. There’s so much pleasure and enjoyment right in front of you — perhaps you don’t need to be anywhere else.

MAKE EVERY DAY AMAZING

THERE’S absolutely no need to move to Mustique, win the lottery, become a