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Age Proof - How to live a longer, happier life: more sleep and more sex

A new "groundbreaking" book on ageing featuring findings from "cutting-edge" research from Professor Rose Anne Kenny's extensive career in the field of ageing will reveal why and how some people live longer, fitter, healthier and happier lives than others. Read the second extract from the book below.

Read the Times UK article here.

There’s more to longevity than good genes, says Professor Rose Anne Kenny in her new book. If you want to live longer, start between the sheets.

Don't count on your good genes

You have more power over destiny than you might think (though this can go both ways.) I recently had to break it to one patient that just because his parents had both died at ripe old ages, this did not mean that, at 68 and overweight, he could continue to smoke and drink with impunity. “Good genes” are not everything. Our genes are responsible for 20 to 30 per cent of our longevity up to age 80 — though they do play a much larger role in how likely we are to live beyond that.

Studying twins has taught us much about genes and ageing because twins have the same genes at birth, and so are genetically programmed to age in the same way. They don’t. Twin studies confirm that up to 80 per cent of survival (or not) until age 80 is determined by external factors including social and economic circumstances, diet, sleep, childhood experiences, alcohol intake, depression, stress and exercise.

And as our complexion exhibits all the hallmarks of cell ageing, we really do wear our age on our face. In a recent experiment in the United States, a twin who smoked for ten years looked two and a half years older than their non-smoking twin, according to an independent panel. Excessive sun exposure also sped up facial ageing, as did stress. Conversely, immersion in cold water is quite the elixir of youth for skin, partly because it improves circulation.

More sex please

No, you’re not past it. It’s a myth that as people age they lose interest in sex. (And most issues that complicate sex in later life can be treated — so trouble your doctor.) A series of landmark reports on older adults’ sexuality by a gynaecologist at the University of Chicago found that many were still going strong into their ninth decade. They also rivalled 18 to 59-year-olds in how often they had at it. So perhaps it’s not surprising that our Tilda research reported that 80 per cent of the couples, with an average age of 64, consider sex important. Sixty per cent are sexually active weekly to twice a month. And data from a recent English study shows similar results.

In terms of ageing this is excellent news. Sexually active older adults have a more positive outlook, and are less likely to think of themselves as old or believe that ageing has negative consequences. Such attitudes contribute to a superior quality of life — and a younger biological age. The data consistently shows that sexually active individuals are happier and less likely to be depressed or anxious. In fact, simply being physically close to another person increases our brain’s levels of oxytocin, the “cuddle hormone”, which makes us feel happy and safe, promoting other good feelings including empathy and trust.

Not only that, other endorphins released during sex generate elation, just as with physical exercise. Indeed, sex is physical exercise. It burns on average four calories a minute, and heart rate can rise dramatically to 180 beats per minute, making sex the equivalent of a speedy treadmill run and probably more fun. Endorphins also play a role in the immune response, so boosting our levels benefits immunity and reduces infections.

There’s more. Seems like sex could be good for us neurologically. Those who keep at it have better memory and concentration. A study, inevitably called Sex on the Brain, involving 7,000 people from 50 to 90, confirmed better mental abilities for planning and memory in sexually active older people. In other words, sex is independently beneficial for brain health. And no need to go all the way — kissing and fondling will do it. Masturbation is also associated with better memory.

What sleep does and how to do it better

We are hard-wired to sleep each night to restore body and mind. Yet in midlife and beyond so many of us suffer from poor sleep — and not always because we’re so busy having sex. So how can we get enough? There are solutions — but first, a brief reminder of how, ideally, sleep works. There are four stages. During the initial three, N1, N2, N3, we gradually fall into a deeper sleep. N3 is the deepest stage, and our eyes don’t move so it is also called NREM, no rapid eye movement sleep. The final stage is when we dream, REM sleep. These four stages make up a single sleep cycle from 60 to 90 minutes. They are all essential for our body’s maintenance and repair.

NREM is the stage most physiologically profound. We release human growth hormone, vital to repair of body and brain cells. Waste products (including those implicated in dementia) are flushed away, tissues repaired and regrown, collagen replenished, bones and muscles built, and the immune system strengthened. NREM decreases anxiety too, restoring activity in areas that regulate emotions and lowering heart rate and blood pressure. In REM sleep, we process the day’s learning, events, thoughts, and consolidate memory. Insufficient REM sleep can lead to issues including mood swings, and impaired memory and concentration.

Poor sleep also affects our immunity. During sleep, the immune system releases proteins called cytokines, whose role is to target infections. Some also promote sleep. Sleep deprivation therefore has a doubly negative impact. Sound sleep meanwhile improves the action of immune T-cells, which fight infection by sticking to viruses, such as flu, and destroying them. But stress hormones such as adrenaline (lower during sleep) decrease their stickiness. It means that good sleepers are less likely to get winter colds and flu, and are better able to fight infection.

Six ways to enhance sleep

  • Mid-afternoon, there’s a brief blip in the body’s internal alertness signal, giving sleep the edge over our wakefulness drive. Should you nap? For some, it preserves function, for others it exacerbates night-time insomnia. A good rule is if you nap, do so before 3pm. It may be that ten minutes is effective — or 20. To revitalise and reboot, 90-minute naps are great, provided you complete the NREM-REM cycle. But tailor any nap habit to suit you.
  • Keep vigorous exercise to earlier in the day. Even a fast walk late in the evening can impede sleep as it alerts the sympathetic system (which triggers our fight or flight response), releasing stimulating hormones, making it harder for mind and body to switch to deep-sleep mode.
  • Digestion disrupts sleep — in particular avoid aged cheese, bolognese sauce, bacon, and other cured meat such as sausage, pastrami and ham as they contain high amounts of tyramine, an amino acid that triggers brain alertness. (Some Italian wines and several beers also contain it. Alas, alcohol disturbs both NREM and REM, so it’s a no-no anyway.) High-carb meals can disturb sleep, as can acidic, spicy, or high-fibre food — so if you are habitually tempted to snack on broccoli before bed, resist.
  • A host of sleep-promoting foods enhance melatonin and neuropeptides such as tryptophan and serotonin. So to alleviate pre-bedtime hunger pangs, choose from almonds, turkey, kiwi, tart cherry juice, fatty fish, milk, bananas, porridge and cottage cheese. Camomile contains an antioxidant that induces sleepiness. Vitamin D and omega oils also improve sleep.
  • Using sound stimulation — such as listening to white or pink noise — can enhance deep sleep. White noise contains every frequency audible to us. Pink noise is white noise with fewer high frequencies. They increase the intensity and slow down the speed of NREM waves, allowing more time to clear toxins, improving learning, memory and reducing anxiety.
  • Until recently, our evolution depended on yellow light (fire, wavelength 570-590nm). Blue-light (wavelength 450-495nm) exposure was limited to a few hours in winter. Blue light suppresses melatonin (the hormone that regulates the sleep-wake cycle) proportional to the light intensity and length of exposure. Simply — the longer the exposure to blue light before sleep, the shorter the sleep. Email checking has the most striking effect (even gaming is less disruptive).

Are you a dolphin, bear, lion, or wolf?

Our genes set our body’s natural timeline when we prefer to eat or sleep, making us either an owl or a lark. But there are four subtypes: so are you dolphin, lion, bear or wolf? Dolphins (10 per cent of us) and lions (20 per cent) are early wakers. Dolphins typically struggle to fall asleep, sleep for about six hours, and wake unrefreshed. Lions, meanwhile, tire by bedtime, and arise full of energy. The wolf, however, loathes mornings, comes to life later in the day and is at its best after dark. The behaviour of bears — deep sleepers and 50 per cent of us — falls between early wakers and wolves.

If you’re a wolf, your circadian rhythm is most out of whack with society — so you’re more likely to suffer from “social jet lag” and feel chronically groggy and fatigued. As your appetite clock is out of sync too, unfortunately you’re more prone to obesity, and to suffer from diabetes, heart disease and strokes. But it’s possible to adjust your patterns by bringing forward your sleep — and, crucially, your food intake — by 15 minutes daily until you reach the desired schedule. Food timings are instrumental. Note, a 16-hour fast overnight, if doable (this goes for all of us), reduces weight and blood pressure and stabilises circadian rhythm.

The 8 age-defying factors of Blue Zone longevity (it isn’t just about diet)

Most of us are familiar with the Blue Zones — those areas in the world where people lead extraordinarily long and healthy lives — Sardinia, Italy; California, US; Okinawa, Japan; Nicoya, Costa Rica; and Ikaria, Greece. All of these populations share similar lifestyle characteristics — a quick reminder of their secrets:

  • Life purpose — the Nicoyans call it “plan de vida” — research shows it can add seven years of life
  • Stress reduction — rituals might include an afternoon nap, or socialising, but downtime is built in
  • Moderate calorie intake — centenarians in these regions stop eating when they’re 80 per cent full
  • Plant-based diet — mainly vegetables and beans, plus fruit, wholegrains, small amounts of meat
  • Moderate alcohol intake — afraid so
  • Engagement in spirituality or religion — for some it’s communal prayers or meditation
  • Engagement in family and social life — close bonds with family and friends, and a sense of belonging
  • Regular physical activity integrated into routine (walking, gardening, housework) rather than the gym

My eating habits for youth and health (this is what I do)

What we eat, when we eat, plus our metabolism and cell energy production are the most important controllers for how our cells age. Once upon a time human activity, including eating, was naturally synchronised to day and night. Today we eat at all hours. The typical eating pattern in, say, the UK, Ireland, or the US is to have breakfast, lunch, dinner and a late-evening snack.

With each meal, blood sugar levels rise, and then return towards baseline over several hours. Sugar is stored as glycogen in the liver. If it’s there, we use it as our energy source. But elevated sugar levels aren’t good for us. Meanwhile, ketones — chemicals that break down fat for energy — are only formed when we fast. Their levels remain low if glycogen is plentiful. Only when glycogen levels drop do we switch to using fatty acids to produce ketones. This then triggers a cascade of chemical reactions beneficial for cell preservation.

A review in the New England Journal of Medicine concludes that changing from fed to fasted state improves metabolism, lowers blood sugar, lessens inflammation and clears toxins and damaged cells. My advice is to eat within an eight-hour window during the day if you can. There are a number of fasting programmes — intermittent, or periodic — that allow time for glucose levels to subside and remain low, prompting a metabolic switch from ketone-based energy production. (I find the 18-hour fast manageable — I skip breakfast, eat lunch and dinner between midday and early evening, and fast overnight till midday. Ketones are elevated during the last six to eight hours of the fast.)

Basics of the Mediterranean diet (robustly linked to longevity and better health)

Vegetables - Tomatoes, broccoli, kale, spinach, onions, cauliflower, carrots, Brussels sprouts, cucumbers

Fruits - Apples, bananas, oranges, pears, strawberries, grapes, dates, figs, melons, peaches

Nuts and seeds - Almonds, walnuts, macadamia nuts, hazelnuts, cashews, sunflower seeds, pumpkin seeds

Legumes - Beans, peas, lentils, pulses, peanuts, chickpeas

Tubers - Potatoes, sweet potatoes, turnips, yams

Whole grains - Whole oats, brown rice, rye, barely, corn, buckwheat, whole wheat, wholegrain bread and pasta

Fish and seafood - Salmon, sardines, trout, tuna, mackerel, shrimp, oysters, clams, crab, mussels

Poultry - Chicken, duck, turkey

Eggs - Chicken, quail, duck eggs

Dairy - Cheese, yoghurt, Greek yoghurt

Herbs and spices - Garlic, basil, mint, rosemary, sage, nutmeg, cinnamon, pepper

Healthy fats - Extra virgin olive oil, olives, avocados, avocado oil

Why fish deserves a special mention

In most Blue Zones, people eat up to three servings of fish each week — typically middle-of-the-food-chain species, such as sardines, anchovies and cod, that aren’t exposed to high levels of harmful chemicals. Trout and salmon, low in mercury, are also great. Many studies show that people who eat fish regularly have a lower risk of heart attacks, strokes and death from heart disease. In one large UK study, following 40,000 people over 18 years, fish eaters were 13 per cent and vegetarians 22 per cent less likely to have a heart attack than meat-eaters. Another study found eating fish also benefits our sleep. (FYI, salmon, three times weekly.)

Farmed and wild fish have similar mercury content (high levels of this chemical have been linked to cardiovascular and brain disease, though data are not definitive), but farmed salmon contains slightly more omega-3, much more omega-6 and more saturated fat. Conversely, wild salmon is higher in potassium, zinc, iron and vitamin D. (NB Vitamin D plays an important role in the immune system — I take 1,000IU daily.) Omega-3 fatty acids, meanwhile, are crucial for optimal brain and body function, and strongly linked to a reduced risk of many diseases, and to get enough, eating fatty fish at least twice weekly is recommended. Vegan or vegetarian? Take an omega-3 supplement made from microalgae.

Supplements — yes or no?

Evidence says no. In a study of almost 40,000 healthy women aged 45 and older, vitamin E supplements did not reduce the risk of heart attack, stroke, cancer or macular degeneration. Another large study found no benefit for vitamin C, vitamin E and beta-carotene supplements on heart disease, stroke or diabetes. Yet diets such as the Mediterranean diet contain these antioxidants — in fruits and vegetables for example — and are proven to help prevent these diseases. So why do antioxidant supplements not confer the same benefits? It may be differences in chemical composition, dosage, or influence of other dietary or lifestyle factors — we’re not sure. But what is certain is it’s better to get our antioxidants from a healthy diet than a pill.


The good bacteria in our gut are crucial to our immune system, heart, weight and a host of other aspects of health. How can we help them, and consequently ourselves, to flourish? Long-lived, fit, healthy people have diverse microbiome — ensured by following a varied diet. Research shows it’s possible to shift the diversity of gut microbiome within 72 hours of changing our nutritional habits — for better or worse. We know that a diet high in sugar and fat-laden processed food changes gut bacteria to microbiota typical of obese people. Whereas the Mediterranean diet prompts microbiome changes linked to better mental function, memory, immunity and bone strength.

So what shouldn’t we eat? My bugbear is emulsifiers — found in all processed foods such as burgers, ketchup and mayonnaise. They increase the level of microbes that produce chemicals associated with obesity and diabetes. Likewise, artificial sweeteners also produce toxic chemicals via microbes.

What should we feast on? Microbes love polyphenols, contained in foods such as peanuts and seeds, raspberries, strawberries, plums, black grapes and prunes, extra virgin olive oil, spices and herbs. High-fibre food is also a favourite — eg wholegrain pasta, oats, barley, rye, pears, melon, oranges, sweetcorn, pulses and potatoes in their skins. If you are taking antibiotics (which reduce gut bacteria) or have IBS, there’s evidence that probiotics help — though try sauerkraut or kimchi rather than supplements. If your gut bacteria are thriving, it’s more likely you will be too.

Age Proof — The New Science of Living a Longer and Healthier Life will be published by Lagom imprint on the 20th of January 2022, Learn more here.