30-SECOND CHALLENGE

... and to wake up, exercise and do the gardening. An Oxford University sleep expert has all the answers ...

START on the left with the number given and follow the instructions as you go across. Within the 30-second time limit, beginners have to complete their own challenge, intermediates have to complete their own challenge AND the beginners’ challenge, and advanced players have to complete their own challenge AND the intermediate. The answers are on

THE shrill sound of your alarm clock rouses you from a deep sleep, forcing you out of bed, groggy and blearyeyed. If this sounds like your typical morning, it might not just be late nights that are to blame. According to sleep expert Dr Paul Kelley, of Oxford University, circadian rhythms (governing your 24hour body clock) vary over a lifetime, ‘meaning there is a different “best time” to wake up and carry out routine activities, depending on your age’.

So, when should we be doing what?

TWENTIES

9.30AM, WAKE UP: ‘Your wakefulness is controlled by two processes in the brain — one that alerts you and another that drives you towards sleep,’ explains Dr Kelley. ‘This is balanced by the release of different hormones: melatonin, the sleep hormone, and orexin, the wakefulness hormone. In a 20yearold, orexin doesn’t override melatonin until midmorning.’ 10AM, DRINK COFFEE: There’s a reason lots of young people don’t eat breakfast — they simply aren’t hungry at this time. ‘For around two hours after waking, we’re in a state called sleep inertia,’ says Dr Kelley. ‘There aren’t enough metabolic processes happening in a twentysomething’s body for them to need much energy from food.’

But caffeine will help them shake off this inertia, by binding to nerve cells in the brain. 12 NOON, START WORK: It won’t please the boss, but at this age, midday is when the brain starts being productive. 3PM, HAVE SEX: The 20yearold libido can experience desire at any time of day. Why not make the most of that midafternoon spike in energy? 3.30PM, LUNCH: Having started your day so late, you won’t need food until now. ‘The European custom of eating a big lunch applies best to 20yearolds,’ says Dr Kelley. ‘This is when they need fuel for concentration.’ 5PM, EXERCISE: Physical performance in this age group is highest between 3pm and 6pm, with lung function 18 per cent more efficient than normal after 5pm. 8PM, FINISH WORK: You reach your mental peak in early evening. 8.30PM, WATCH TV/USE YOUR iPAD: ‘It’s a good idea for twentysomethings to slot screen use into the early evening when the brain is still alert from work,’ says Dr Kelley. 9.30PM, DINNER: Europeanstyle again, to provide an energy boost for the evening. 10PM, STUDY: Research has shown young people are better at creative thinking late at night. 11PM, HAVE A DRINK: Those in their 20s tend to have a higher alcohol tolerance. ‘The usual advice is to never drink later than four hours before bed, as the chemicals remain active in your bloodstream,’ says Dr Kelley. ‘But young people are an exception.’ 12AM, SWITCH OFF THE iPAD: ‘The blue light the screen emits temporarily alerts you,’ Dr Kelley explains. ‘Switch it off an hour before sleep.’ 1AM, SLEEP: A later bedtime means you’ll need a liein the following day.

THIRTIES

8.10AM, WAKE UP: ‘There’s quite a jump between 20 and 30,’ says Dr Kelley. ‘Your brain, lungs and muscles have started to age, so your body clock shifts earlier to maximise the time it is alert.’ 8.20AM, HAVE SEX: Sunlight boosts testosterone in both sexes by stimulating the hypothalamus (the part of the brain responsible for hormones), making intercourse at this time ideal. 8.40AM, BREAKFAST: Just avoid sugary or starchy foods, which will make your blood sugar levels spike then dip. 10.40AM, START WORK: The hormone cortisol reaches a natural peak, giving the 30yearold brain a boost of alertness. 2.10PM, LUNCH: Have something rich in protein now. If lunch is left too late, the organs start to draw on the body’s glucose reserves, making us feel irritable. 3.40PM, NAP: If you’re a new parent lacking in sleep, now is the time to sneak away for a 20minute powernap. 6.40PM, FINISH WORK: Stopping in the early evening makes the most of the afternoon spike in concentration that a late lunch provides. 7PM, EXERCISE: In this stage of life, muscles still work better later in the day, when they’ve fully warmed up. 7.45PM, SOCIALISE: ‘Early evening is when your mood improves and your capacity for thinking and communicating is highest,’ says Dr Kelley. 8.10PM, DINNER: A 30yearold needs food around 90 minutes after finishing work. It’s also a good time to have a drink — at this age, the liver metabolises alcohol efficiently. 10PM, WATCH TV/USE YOUR iPAD: ‘ Limiting your exposure to artificial light makes for better sleep,’ warns Dr Kelley. 11.40PM, SLEEP: By your 30s, you rely on restorative sleep to consolidate memories and improve alertness the following day.

FORTIES

7.50AM, WAKE UP: ‘Your wakefulness cycle “wins” over your sleep cycle much earlier by the time you hit 40,’ explains Dr Kelley. 8.20AM, BREAKFAST: In this decade, you’ll have tossed and turned, burning energy during the night. A highfibre meal will leave you feeling fuller longer. 8.45AM, TAKE A WALK: This will get blood pumping through sleepy muscles. Physical activity is a morning must to stop limbs seizing up later. 10.20AM, START WORK: Enough time has elapsed for sleep inertia to have worn off. 10.45AM, DRINK COFFEE: Early in the day, the 40yearold body is flooded with cortisol, meaning it is ‘naturally caffeinated’, so a boost is needed only now. 1.50PM, LUNCH: ‘Waiting until later to eat

is good for you, as it stops that midafternoon energy slump,’ says Dr Kelley. 3.30PM, HOUSEWORK: An ideal time to roll up your sleeves. hand-eye coordination is at a high, and endorphins surge, minimising the risk of aches and pains. 6.20PM, FINISH WORK: Doing so roughly 80 minutes after the usual nine-to-five day allows you to make the most of the energy acquired at a late lunch. 7.50PM, DINNER: eating before 8pm gives your body maximum time to digest the food before bed. 10.20PM, HAVE SEX: ‘This can enhance relaxation by releasing oxytocin, which promotes rest,’ says Dr Kelley. 11.30PM, SLEEP: Maximise restorative slumber by turning in before midnight.

FIFTIES

7AM, WAKE UP: By your 50s, the brain shuffles quickly in and out of moderate-level rest at night, spending only a few minutes a night in the deepest phase. 7.30AM, BREAKFAST: Metabolism slows around five per cent for every decade after 40, so re-fuelling at the right time is crucial to mobilise ageing muscles. 8AM, GARDENING: ‘Morning light is brilliant for regulating your body clock and ensuring all biological processes — from digestion to temperature control — happen as they should,’ says Dr Kelley. 9.30AM, START WORK: Your alertness and concentration will be at a natural high. 1PM, LUNCH: A big meal is best now rather than in the evening. ‘As 50-year-olds get up earlier, they need to eat earlier,’ says Dr Kelley. 2PM, NAP: ‘There’s a reason most car accidents happen at 2pm,’ Dr Kelley explains. ‘Most people this age experience a “post-prandial dip” — fatigue caused by a drop in blood glucose caused by the body secreting insulin, in response to the glucose consumed during lunch.’ 5.30PM, FINISH WORK: By your 50s, you may be experiencing mild memory loss or lapses in concentration, which worsen with tiredness, so knock off work now. 6PM, HAVE A DRINK: Liver function is slower at 50, so give your body at least four hours to process alcohol before bed. 7PM, DINNER: At this age, regular mealtimes are crucial for maintaining low cholesterol and reducing the likelihood of heart disease. 9.30PM, SWITCH OFF THE TV/iPAD: Limit screen time to an hour, stopping 60 minutes before sleep to avoid exacerbating the early stages of arthritis. 10PM, HAVE SEX: With so much activity in the morning, intercourse is better timed at night. 10.30PM, SLEEP: ‘Make sure the bedroom is dark and cold for a restful night,’ adds Dr Kelley.

SIXTIES

6.30AM, WAKE UP: ‘Your body is well aware of the beneficial effects of sunlight and it naturally rouses early, like you did

as a child,’ Dr Kelley explains. ‘Getting up at this time sets your body on schedule for the day.’ 7AM, BREAKFAST: For an early energy boost try blueberries — they activate an enzyme called eNOS that increases the flow of blood and oxygen to the brain. 8AM, EXERCISE: Try yoga or Pilates outdoors to make the most of the sunlight and warm up muscles. 9AM, START WORK: ‘By 60 you [your body clock] have reverted to the conventional nine-to-five working day,’ explains Dr Kelley. ‘ Creative connections in the brain, known as synapses, are at their most active.’ 10AM, DRINK COFFEE: Over-60s are the biggest caffeine addicts. Consume it in the middle six hours of the day. 12.30PM, LUNCH: In this age group, taste buds are most sensitive between 11am and 1pm, making lunch more enjoyable at this time. 1.30PM, HOUSEWORK: In your 60s, you have more energy in the early afternoon and your eyesight is also at its best — good for fiddly chores. 2PM, NAP: ‘Only do this if you’re tired,’ says Dr Kelley. ‘Try drinking a cup of coffee beforehand to make sure your body wakes up on cue.’ 5PM, FINISH WORK: If you still work, head home before your energy lags. 6.30PM,6.3 DINNER: By scheduling dinner ea early, 60-year-olds minimise the risk of he heartburn and indigestion. 7.30PM,7.3 SOCIALISE: ‘Social engagem ment can be hugely beneficial to he health at this age,’ says Dr Kelley. ‘e ‘early evening strikes a good balance be between wakefulness and low stress.’ 8PM,8 HAVE SEX: Sufficient time has passed since dinner, priming your body to be flooded by oxytocin, which is released after orgasm. 9PM, SWITCH OFF THE TV/iPAD: Your eyes are more sensitive to artificial light in your 60s, so turn screens off an hour before bed. 9.30PM, READ/DO A CROSSWORD: Mental stimulation before bed sets up your brain to work on memory formation and repair at night. 10PM, SLEEP: At 60, the sleep hormone melatonin spikes around this time.

SEVENTIES

6AM, WAKE UP: ‘ Your biological processes naturally start half an hour earlier,’ says Dr Kelley. ‘Make the most of feeling alert.’ 6.30AM, BREAKFAST: Scientists say older people benefit most from an early breakfast, jumpstarting a slowing metabolism. 7.30AM, EXERCISE: An early brisk walkw is important. ‘It gets all the musclesm in the body warmed up nicely,’ni says Dr Kelley. Aerobic exercisecis (anything that makes you slightly outou of breath) boosts concentration. 8.30AM,8. START WORK: If you have an administrativead task to complete, turn youryo attention to it now. 10AM,10 SNACK: By 70, your body is usingus up energy reserves faster in orderor to perform routine mental and physicalph tasks, so have a snack now. 11AM,11A READ/DO A CROSSWORD: ‘This is theth time of day when brain power is at a high,’ says Dr Kelley. 12PM,12 LUNCH: It’s early, but you’ll ne need fuel. have your last coffee of the da day now, too, as caffeine takes around a third longer to be absorbed at this tim time of life. 2.30PM,2. NAP: experts say a 20-minute daytimeda nap can help those in their 70s70 have a better night’s rest. 4PM,4P FINISH WORK: As concentration wanes,wa stop mentally taxing tasks. 5PM,5P ANOTHER WALK: ‘Getting a blast of natural light late in the day can givegi you energy for the evening, withoutwi disturbing your precious sleepsle later on,’ says Dr Kelley. 6PM,6P DINNER: eating earlier gives the 70 70-year- old body time to digest pr properly and lowers the risk of acid re reflux. If you want a drink, have it af after your meal, on a full stomach. 7PM,7P WATCH TV: The eyes and brain ar are very sensitive to blue light, so limit vie viewing to an hour well before bed. 8PM,8P HAVE SEX: ‘The recommended tim time of day as it can help you relax an and drift off to sleep,’ says Dr Kelley. 9.30PM,9. SLEEP: A healthy 70-year-old m may wake several times in the night du due to a naturally shallow sleep cycle, so turn in early to maximise your ch chances of a full night’s rest.