Follow-up the wise body clock!

An experts guide to living by the body clock

By Philip Sherwell
30/12/2007
http://www.telegraph.co.uk/news/main.jhtml...0/nclock130.xml

Millions of us will resolve this new year to lead a healthier life. But do we really understand how best to do so? Philip Sherwell explores a new guide to a day in the life of the body

The Ackerman household knows all about the mysterious rhythms of the body.

Jennifer Ackerman believes our internal body clock dictates the optimal times for rest and excercise

She puts aside time in late morning for her most important work or mulling tough decisions, encourages her family to take a nap after lunch and schedules dentists' appointments for early afternoon.

She prods her husband, Karl, and the girls to exercise or play sport in the late afternoon or early evenings and sometimes allows herself a drink or two at cocktail hour without worrying unduly about the impact.

Mrs Ackerman lives life by the clock with good reason: she is an expert in what she calls "the drama unfolding inside" during 24 hours in the life of the typical human body.

The American science writer has captured that excitement in her newly published book Sex Sleep Eat Drink Dream - its fascinating revelations about the secrets of our body's workings are particularly topical as people mull over their New Year's resolutions following the excesses of Christmas.

"We tend to think of ourselves as cerebral creatures, driven primarily by what's going on in our minds,"

Mrs Ackerman told The Sunday Telegraph. "But more often than not, we're also driven by what's transpiring south of our brains - by the hidden ups and downs, the little crises and triumphs of our bodies, which cycle over the course of a day."

Mrs Ackerman began her investigations into our daily body clock after a debilitating case of influenza. "Like most people, I had been a pretty unappreciative owner of my own body and only really paid attention to it when it did me wrong," she explained. "After that attack of the flu, I decided to learn how my body worked."

The result is a guide - mixing science and anecdote - to the body's peaks and troughs, from early morning (when the breed she identifies as "larks" flourish) to the evening domain of "owls". Among the many explanations of those rhythms: our body temperature swings from a low of about 97F (36C) in the early hours, to a high of 99F (37C) or more by late afternoon, affecting performance and function throughout the day.

The book investigates the 24-hour internal body-cycles, known as circadian rhythms (from the Latin circa, "around" and diem, "day"). The formal scientific study of these fluctuations is called chronobiology.

Body temperature, heart rate, blood pressure and hormone levels all vary according to the time of day, with profound implications for how we function during the course of 24 hours.

The master clock in the brain is formed by two clusters of 10,000 neurons in the hypothalamus, located just behind and below both eyes, Mrs Ackerman explains, and these control the major circadian rhythms of the body (of which the sleeping-waking pattern is the most obvious).

But, she continues, the system is much more complex than that. "We now know that the body has not one clock, but billions. Circadian timekeepers are ticking away in virtually every bit of flesh, in kidney, liver and heart, in blood and bone and eye.

"Though the master clock oversees the body's cyclical rhythms, the genetic timepieces pocketed in the cells of our outlying tissues and organs may follow their own daily routines, triggering peaks and troughs of activity at different times of the day in their respective locations."

Drawing the sort of comparison that makes the science comprehensible for the general reader, she speaks of these peripheral timepieces as the instrument sections of an orchestra and the master clock as the conductor.

Here is some advice from Mrs Ackerman for those drawing up their resolutions for 2008. The good news is that failures in previous years may owe less to lack of resolve than to ignorance about how our bodies work.

Losing weight

Eat more… in the morning. "Start the day with a large, healthy breakfast," Mrs Ackerman recommends. "Avoid the tendency to skip breakfast or grab a snack for 'desk-fast'. Not only does a hearty morning meal rev up your metabolism, it also better satisfies your appetite.

This may be because the mechanism in the brain that makes you feel satiated is more effective then than later in the day.

The reverse also applies - don't eat late at night for the same reasons."

She cites a series of studies that show that eating a hearty breakfast reduces calorie intake over the day. And she makes sure her family practises what she preaches. Her 15-year-old daughter, Zoe, downs a big bowl of oat-grain cereal with skimmed milk; Nell, 12, prefers toast, eggs and bacon; Karl, typically has a bagel with the all-American combination of peanut butter and jam; while Mrs Ackerman usually has pitta bread with cheese, followed by wholegrain cereal.

Another insider tip for those who want to lose weight is to get more sleep. A lack of sleep reduces the body's supply of leptin, a hormone that plays a key role in regulating appetite, and the drop in those levels produces a craving for calorie-rich food. "Sleep loss is a recipe for weight gain," she explains. "Indeed, some nutritionists contend that America's obesity epidemic is tied to an epidemic of sleep deprivation."

Exercise

Losing weight and getting fit normally go hand-in-hand on the resolution wish-list. And if your regime at the gym has failed in previous years, it might just be that you were working out at the wrong time.

Those, such as the US secretary of state Condoleezza Rice, who kick off the day with a power session on the treadmill are often wasting their energy. "Your body is at its physical peak from about 3pm to 8pm when your body temperature has warmed up, your joints are more flexible and your heart is pumping most effectively," says Mrs Ackerman.

Drinking

If you want to rein in your drinking, then Mrs Ackerman has a simple mantra: "Save cocktails for cocktail hour.

Skip the three-martini lunches and the nightcap." Early evening is the optimal time for metabolising alcohol, as the body's temperature has risen during the day, thus speeding up the chemical reaction that detoxifies the drink and reducing its impact on organs and faculties.

By contrast, drinking at lunchtime exacerbates the natural performance dip that our bodies go through in the early afternoon. And although drinking late at night can make you feel initially drowsy, the alcohol often disrupts sleep during the night as the body processes it.

Sleep, sleep, sleep

For health, mood, work and performance, Mrs Ackerman prescribes a straightforward remedy - more sleep. "Most of us are getting too little sleep and sleep loss has a cumulative impact on our alertness, efficiency and thought processes. Sleep loss also has a negative impact on our immune system so you are more likely to get sick, it impairs the body's ability to process blood sugar and may lead to weight gain."

She insists that she and Karl get seven to eight hours a night, while for her growing, energetic daughters, it is nine to 10 hours. She also encourages a restorative early afternoon nap - her husband follows her advice, but her children, she admits, rarely do. "I am campaigning for the adoption of the siesta," she says. "It's a way to catch up on lack of sleep at night, but also, it's a good way to improve mood and boost productivity and alertness at a time of day when we have a natural rhythmic dip."

Keep life simple

Resolve to cut out the multitasking - Mrs Ackerman's research has taught her that the brain copes much better with concentrating on individual tasks in sequence. "I used to multitask a lot, thinking I was getting more accomplished that way.

No more. I realise now that it's safer, more efficient and more productive to do one thing at a time and devote my full attention to it."

Trying for a baby?

Our sex lives may be out of sync with our body clocks, it emerges. "The timing of sexual activity tends to be dictated by the clock on our nightstand not in our bodies," Mrs Ackerman explains. "It is determined by our family and work cycles, not the rhythm of our bodies.

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The most common time for sex by far is late at night, followed in a distant second place by mornings.

Testosterone peaks around 8am and sperm count in late afternoon. Indeed, some fertility experts recommend afternoon sex to improve chances of getting pregnant."

Mrs Ackerman's book argues that knowledge of our daily rhythms can help us make the best personal choices. So the reason that she schedules interviews and meetings for late morning and also saves important life decisions for that time slot is that our mental performance is normally at its zenith three or four hours after we wake. Dental appointments are early or mid afternoon because that's when our pain threshold is at its height.

Conveniently for most men's morning ablutions, 8am is the best time to minimise bleeding when shaving, as clot-forming blood platelets are at their most abundant and stickiest then. For the same reason, heart attacks peak around the same time.

And the favourite statistic that Mrs Ackerman came across in the course of her research?

By cell count, our bodies are 1 per cent human and 99 per cent microbial (germs, bacteria and viruses). "Our bodies are a composite," she said. "We're more like an ecosystem than an individual organism."

Her journey of discovery through the body's workings has changed her life. "I am far more conscious of how my body's fluctuations - of temperature, stress hormones, blood pressure, heart rate, alertness, among other things - affect the way I function and how I feel," she said.

"I'm more attuned to the importance of timing basic daily activities and I'm far more respectful of the body's needs, from regular exercise - which is good not only for body but for brain - to frequent laughter (which boosts blood vessel health), enough natural light (to keep the body's rhythms in synchronicity with shifting seasonal cycles of light and dark), and especially, adequate sleep.

"Your body is often smarter than you think, and it almost never lies.

You owe it to yourself to get to know it better. By listening to its signals and paying attention to its rhythms, you can boost your health, your productivity, even your mood. Talk about a kick-start for the new year."