The best times to stay healthy

Working out early in the morning can put you more at risk from infection, according to research published this month by Brunel University. This study flies in the face of conventional advice and is based on the way our in-built body clocks - or circadian rhythms - work. And, according to our body clocks, there is a best time for everything.

Best time to ... get up

Ideally, we should get up around 6am. We all have an internal body clock which runs on a cycle of 24.5 hours. "It's running slightly slow, so we need to reset it daily by exposing ourselves to environmental cues, such as light," says Dr Lance Workman, lecturer in biological psychology at the University of Glamorgan "The most efficient way to reset our clock is to get up at the same time each day." As many of us allow our clocks to free-run at weekends, this explains groggy Monday mornings, adds Professor Simon Folkard, director of the Body Rhythms and Shiftwork Centre, University of Wales.

... start eating

On the meridian-point system (similar to acupuncture), between 7am and 9am is the "large intestine time", so a healthy breakfast is the best way to kickstart digestion. Vicki Edgson, nutrition consultant and co-founder of The Food Doctor Clinic, says: "It's a good idea to drink hot water mixed with a slice of lemon or a few slices of raw root ginger, which will stimulate the digestive system. Within half an hour, eat a breakfast of, say, good quality bioyoghurt with fruit or scrambled eggs on toast to keep your blood-sugar balance stable."

... be mentally alert

The level of the hormone cortisol is at its highest between 8am-9am. "Produced by the adrenal glands, this hormone activates bodily functions, boosting brain function, raising blood pressure and bloodsugar levels," says Professor Stafford Lightman, director of Neuro-Endocrinology at Bristol University.

"This means you'll have a better memory and a slight physical advantage first thing in the morning. Cortisol levels rise at 6am, preparing the body for the day, then slowly fall away after 9am, though hard physical exercise can stimulate further cortisol production." However, Professor Lightman adds that long-term memory and the ability to assimilate information tends to peak in the afternoon.

... have a dental check-up

If you're anxious, Dr Tom Rands, senior dentist at Reading Boots Dentalcare, recommends booking the first appointment "when you're less likely to be kept waiting". However, Dr Workman points out that people's pain threshold is naturally at its highest in the afternoon, so 3pm might be a better time.

Dr Rands adds: "Hormonal changes make gums swell a week before a woman's period. Some women experience more tenderness or bleeding then, so you might want to avoid a trip to the hygienist at these times."

... apply sunscreen

At least 30 minutes before you go out into the sun. "Suncreams take half an hour to become fully effective," warns skin specialist Sally Penford.

...eat your main meal

This should be between 12.30pm and 2pm, as your metabolism is highest now. "Those who eat a late lunch will find it takes longer to digest and feel sleepy as a result," says The Food Doctor's Vicki Edgson. "Good lunch choices combine protein, carbohydrate and fibre and include tuna nicoise salad or a baked potato with beans, sweetcorn and vegetables."

... buy new shoes

You should always try on new shoes from 3pm onwards, particularly if you're buying shoes for work, recommends chiropodist Lorraine Jones. "Our feet can swell by as much as one shoe size by mid-afternoon, so if you buy shoes first thing, then wear them all day, they could become painful."

...have an eye test

Late afternoon is best, "because if you're experiencing any symptoms, such as dryness, headaches or red eye caused by an allergic reaction, they're most likely to show up after a long day at the office, and you should always have a test when any symptoms are present," says Dave Cartwright, professional services director at Boots opticians.

There are exceptions to this. "Blood pressure tends to be higher in the morning, so if you've had a highpressure reading in the late afternoon and have suspected glaucoma, you should have another reading in the morning," adds Cartwright.

... exercise

According to the latest research from Brunel University in Middlesex, 6pm is the best time, because levels of the chemical IgA, which helps to protect the body against infections, are down dramatically in the morning, leaving early exercisers open to infection. Previously, it was thought that the optimum time was first thing in the morning, as exercise kickstarts your metabolism, which is at its peak in the morning.

But Kathryn Freeland, MD of personal-training company Absolute Fitness, believes it depends on the type of exercise you are doing: " Ideally, you should do high-intensity exercise early on and progress onto yoga and Pilates later."

... eat dinner

Try to eat no later than 8.30pm. "And at least a couple of hours before you go to bed," says The Food Doctor's Vicki Edgson. "If you don't allow your food to break down in your digestive system, you'll feel uncomfortable and upset your blood-sugar balance, and you are more likely to wake in the night." Ideally, you should eat a light meal, such as fish and vegetables, with no rich sauces.

... floss your teeth

"I'd always recommend flossing in the evening as you're more likely to have the time to do it efficiently," says dentist Dr Rands. "Also, it's important to clear away food debris before sleep, as when you aren't eating, drinking or chewing gum, you're not producing the saliva which can act as a buffer against bacterial build-up."

... go to sleep

A 10pm bedtime is ideal. "There's a lot of truth in 'early to bed, early to rise ...' Our natural circadian rhythms mean that our bodies expect us to sleep earlier than most of us go to bed nowadays," says Professor Folkard. "Studies show that those who go to sleep very late are far more likely to feel depressed. Early nights make you cheerful."

Changes in body temperature are also significant. Body temperature fluctuates by about two degrees Fahrenheit in a 24-hour period - being coolest around 3am to 5am and warmest between 7pm and 9pm. "Your body naturally sleeps when it's coolest, which is why long sleeps in the afternoon, as your body approaches its warmest time, aren't a good idea," adds Dr Workman.

... conceive

A woman is most likely to get pregnant between days 12 to 16 of her monthly cycle, which is when the egg is released. "The egg survives for between 24 and 48 hours, but sperm has the potential to survive for up to 10 days in the uterus. Combine this with an unpredictable 'fertile period' and you can see why the rhythm method of contraception is so unreliable," says Richard Kennedy, consultant gynaecologist and secretary of the British Fertility Society.

... get a massage

Book a deep-tissue massage as late in the day as possible and definitely not before you plan to go out drinking or eat a heavy meal. "Stimulating the lymphatic system through massage helps the body to get rid of toxins," says skin specialist Sally Penford at the International Dermal Institute (a training centre for therapists).

"Some spas provide massages just before you go to bed, when the body can do its reparative work. On the other hand, an energy-based technique, such as shiatsu, can revitalise you first thing in the morning."