The problem with any of these approaches is that you would just be training for a particular test, which misses the point. It's not the push-up itself that makes you live longer; it's that you are still strong and nimble enough to execute one.

What these tests have in common is they're good shorthand of things that matter for longevity: overall health, fitness and muscle strength. A fit person walks faster than someone out of shape, and getting up off the floor is tricky for people with weak bones and muscles.

"Frailty is a really bad thing starting in middle age, and even worse as you get older," says Michael Joyner, a physician and human physiology researcher at the Mayo Clinic.

One way to think of longevity is "not as some magic property of a body, but as the lucky state of not having a fatal disease", says Steve Cole, professor of medicine and psychiatry and bio-behaviouralsciences at the UCLA School of Medicine. "By and large, people don't die of being old; they die of disease." Therefore, the study of longevity is a way of looking at disease risk or the rate of disease development, he says.

Over the years, various drugs and nutritional supplements have been studied for their potential to help us live longer, but nothing has been shown to work in humans to the extent that would be required for the Food and Drug Administration's approval, says Gordon Lithgow, chief academic officer at the California-based Buck Institute for Research on Aging.

While researchers continue searching for a pill to extend life, you'll have to try these verified methods.

The most powerful way to promote longevity and improve your long-term health is also simple and, depending on how you do it, free.

"There's no question that exercise is the biggest anti-ageing medicine there's ever going to be - it's really huge," Lithgow says.

"Hands down, nothing compares to exercise," says Laura Carstensen, founding director of the Stanford Center on Longevity. "The great thing is that most people can do it, and you don't need 10,000 steps per day to get the benefits." It takes remarkably little exercise to get longevity benefits.

Even 10 to 15 minutes a day provides measurable rewards, says Michael Joyner, a physician and human physiology researcher at the Mayo Clinic. Going from sedentary to even just a bit of exercise is where you get the biggest payoffs. The health benefits - such as reducing your risk of heart disease and diabetes - increase with greater amounts of exercise, until you get to about an hour of exercise per day. After that, the rewards start to level off.

"Almost anyone doing more than that is doing it for things other than health," Joyner says.

Go ahead and train for that Ironman if that's what you want, but if you're exercising for health and longevity, you don't need to run a marathon. Work by Iowa State University epidemiologist Duck-Chul Lee suggests that even running a little less than 10 minutes a day could decrease your mortality risk by about 30 per cent.

But you don't have to run. Walking or other moderate activities are just as good if you're looking for a longevity boost.

Some of the early evidence for the heart benefits of moderate exercise came from studies in the 1950s by British epidemiologist Jeremy Morris showing that conductors on double-decker buses, who spent their shifts walking up and down, had lower rates of coronary heart disease and thus lived longer than bus drivers who spent their workday sitting. Since then, studies showing the cardiovascular benefits of exercise have been "incredibly consistent", Joyner says.

But there's more. Physical activity also reduces the risk of diabetes, which one study found shaved six years off life expectancy.

And it keeps your brain healthy, too. "Exercise has better effects on cognitive performance than sitting around playing brain games," Carstensen says. A 2006 study in Neuroscience found that exercise spurs the brain to release growth factors that promote new connections between neurons, keeping the brain healthy. There's even research suggesting that strength training can reverse some age-related changes in your muscles.

There seems to be something about keeping an active lifestyle, too.

When you look at centenarians as a group, they might not be Arnold Schwarzeneggers, but they typically maintain a high level of physical function, says author Bill Gifford, who interviewed quite a few of them while writing his book, Spring Chicken: Stay Young Forever (Or Die Trying). "They can go up and down stairs, probably because they never stopped going up and down stairs," Gifford says.

His research for the book spurred him to make sure he was exercising at least a little bit every day.

Extend your life span while you sleep. It sounds like a bad infomercial, but it turns out that sleeping well is a good way to keep your body healthy for the long haul. Sleep is a time when your brain gets caught up on maintenance. In 2013, a team led by Maiken Nedergaard at the University of Rochester Medical Center published a study in Science concluding that sleep helps the brain clear out metabolic waste that accumulated during waking hours, providing a kind of restorative maintenance.

Skimp on sleep, and you hinder this important work.

If you've ever missed a night of slumber, you know that sleep deprivation hampers your mood and makes it hard to think clearly, but it can have severe consequences for your metabolic health, as well. Take someone who needs seven hours of sleep a night and restrict them to only five hours of shut-eye for five nights and they experience metabolic changes that look a lot like diabetes, says Satchidananda Panda, who studies circadian biology at the Salk Institute for Biological Studies.

Indeed, numerous studies have shown that sleep deprivation can decrease insulin sensitivity - a measure of how well your body regulates blood sugar - and increase your risk of diabetes. A 2015 meta-analysis found that Type 2 diabetes risk was higher in people who sleep less than seven hours or more than nine hours, compared with people who got seven to eight hours a night.

So why is sleeping more than nine hours associated with greater mortality? "People who sleep 14 hours per day are probably not healthy," Carstensen says, but it's hard to say right now whether it's possible to get too much sleep. Most people are on the other end of the spectrum.

Regularly sleeping too long may indicate a health problem

The consensus among sleep researchers is that seven to eight hours of sleep is ideal, but that's just a best guess based on the current data, Carstensen says.

"The biggest problem is that most of the data is self-reported and people are really bad at that," Carstensen says.

The advent of sleep trackers can help with the measurements, but they aren't always accurate, so avoid fixating too much on the exact numbers or you may end up in a cycle of anxiety that prevents you from sleeping. The problem is common enough that researchers have coined a term for it - orthosomnia.

Don't make a habit of skimping on sleep during the week with the idea that you'll catch up on the weekends. It doesn't take many nights of short sleep to reduce insulin sensitivity, and a small study published this year in Current Biology found that recouping on sleep over the weekend didn't entirely make up for the metabolic problems that developed during sleep deprivation. Furthermore, when volunteers in the study were given the opportunity to catch up on sleep over the weekend, they ended up shifting their body clocks so that it became harder to get up on Monday morning.

(Getting enough sleep every night might also improve your work life. In the throes of writing his book, Gifford made a decision to start prioritising sleep over work. His deadline was fast approaching, and he'd been getting up early and staying up late. Allowing his body to sleep as long as it needed to led to a "radical transformation in my ability to write", Gifford says. "I'd been trying to work 14 hours per day, and then suddenly I was getting twice as much done in six or seven hours.")

Forget all those headlines you've seen about "anti-ageing diets" and anti-aging "superfoods".

"These notions are generally not supported by science," Lithgow says. That's not to say diet isn't important, only that "nutrition is just a very difficult science", he says.

Severely restricting calories in lab animals makes them live longer, but "it's not clear that it works in humans", Lithgow says. Although there's plenty of evidence that it's not good to overeat, he says, whether drastically limiting food intake can extend life in people remains an open question. The joke, of course, is that calorie restriction will surely make your life seem longer.

It might be possible to get some of the benefits of calorie restriction without giving up so much food. Intriguing work by Panda suggests that restricting the timing of when you eat, rather than the amount, might provoke some of the healthy metabolic changes that reduce the risk of diabetes. Most of these studies have been done in mice, however, and Panda acknowledges that the human studies are small.

Although Panda is confident enough in the results to have written a book, The Circadian Code, which includes instructions on how to try it, some scepticism is warranted, Joyner says.

"Time-restricted eating has shown some interesting results in small studies," Joyner says, but "will it be sustainable over time in the real world? This is important because most dietary strategies work only if they are adhered to."

He says he wonders whether the metabolic benefits that Panda has found with time-restricted eating is really about the timing or simply related to people eating less when their dining hours are restricted. One thing shown repeatedly in anti-ageing studies is that things that initially look like magic bullets never live up to their initial hype, Joyner says.

What does seem clear, however, is that metabolic health is important for long-term health, because it keeps diabetes in check and that insulin sensitivity in particular appears crucial.

Given what we know right now, a Mediterranean diet - with its heart-healthy emphasis on fish, vegetables, fruits, nuts, healthy fats like olive oil, whole grains and limited consumption of red meat - "is probably the best approach for improving longevity", Carstensen says.

But the benefits are pretty modest. If you hate eating that way, then the payoff probably won't feel worth it to you, she says. At least try to eat a diet rich in fruits and vegetables.

The idea of red wine as a health elixir became popular in the 1980s with the observation that rates of coronary heart disease were low in France, despite the predominance of a diet relatively high in fat and cholesterol. The French penchant for a glass of red wine with dinner was proposed as an explanation for this "French Paradox", popularisingthe notion of red wine as heart helper.

Subsequent studies have indeed found that moderate alcohol consumption may reduce the risk of coronary heart disease, and a two-year randomisedclinical trial in Israel showed that people with Type 2 diabetes who were assigned to drink a glass of red wine with dinner every night experienced some improvements in blood markers associated with cardiovascular disease risk.

But other studies suggest that alcohol may raise the risk of many cancers, and a report published last year in the journal Lancet concluded that there's no amount of alcohol that improves health. What gives?

"Alcohol studies are very much like nutrition studies - based almost exclusively on self-reports, and we know that people are really bad at self-reporting," Carstensen says. "Most people, when they say they're drinking two drinks per day, are probably consuming more. We don't know the amounts that people are consuming nor do we know what else they do."

There's some evidence that people who abstain from alcohol are sicker or less healthy than those who imbibe a little.

"That probably reflects not a lack of alcohol in their system, but something about their world - that they're sick or isolated or don't have friends to meet at the pub," Carstensen says. "I've never seen a study that's really controlled for all of those factors." Which means that the studies calculating the health consequences of alcohol consumption depend on consumption figures that are inherently unreliable and may fail to account for other factors that could be at play.

Drinking to excess - more than one or two drinks a day - is unhealthy, and will take a toll on your longevity - no doubt about it. But taking the published studies together, "I don't think we have a lot of evidence that moderate alcohol is bad for you," Carstensen says. At the same time, she'd "be very hesitant to recommend that people who don't drink should start".

In today's world, it's easy to live in a state of chronic stress, and the problem isn't just that stress feels lousy. It also makes you more susceptible to diseases that could shorten your life.

Researchers are now learning that many conditions associated with older age - such as cancer, heart attacks and Alzheimer's disease - share a common ingredient: inflammation.

Under normal conditions, inflammation is simply the body's response to injury - it's how the body heals cuts and wounds and other insults, Cole says. "Inflammation by itself is not inherently evil." But when we're feeling chronically threatened or under siege, our bodies amp up their inflammatory machinery to ready our biological response to injury, and that inadvertently fuels the development of an array of age-related diseases, where inflammation is a common fertiliser, Cole says.

Research has identified chronic stresses that can provoke harmful biological changes, including living in poverty, caregiving for a dying spouse, losing a loved one, suffering post-traumatic stress disorder, and experiencing prejudice.

"Any way of feeling threatened or insecure seems to be enough to activate the body to produce more inflammation," Cole says. "This is one of the best defined connections between the world as we experience it and how we end up generating a body that's a fertile ground for the development of these diseases."

Your chance of developing chronic inflammation also rises with the passing years. "Inflammation seems to be a general sign of aging, where our inflammatory processes are being turned on or accumulated," Lithgow says. "Age-related inflammation is very much like inflammation from an injury, but now it's coming on without a source of infection."

What's the antidote? "Obviously we should all just be happy," Cole says with a laugh, as if it were that easy. He knows that it's not and says you probably can't eliminate stress from your life, but you can find ways to manage it. Identify the recurring stressors in your life, and work on a plan to diffuse them.

Wellness strategies such as yoga, tai chi and meditation can reliably help diffuse stress, Cole says, although he acknowledges that they often don't make a huge difference.

Forging connections with other people has been found to be a powerful way to manage stress and improve your overall wellbeing.

"People who report having stronger relationships live longer than people who are socially isolated," Carstensen says. A meta-analysis published in 2015 calculated that loneliness and social isolation were associated with 29 per cent and 26 per cent increases in mortality risk, respectively, and living alone was linked to a 32 per cent increase risk of dying.

What's clear is that people who have a strong sense of purpose and meaning in their lives have a markedly lower risk of death than those who don't.

"How we can bottle that and make it useful is more of a challenge," says Cole, who has studied loneliness and longevity.

Telling a lonely person to stop being lonely doesn't work, Cole says, "but if you can go to the lonely person and say, 'Hey, we really need your help. Is there anything you can do to help others?' - that is incredibly powerful. The mechanism here seems to be turning attention away from yourself and your own suffering and toward a community or cause greater than yourself."

Centenarians tend to have a sense of purpose in their lives.

"It's really important that people who are entering the later phases of life have a clear purpose, something to get up for every day," Lithgow says. That thing can be anything from looking after a grandchild or working or tending a garden.

Many centenarians continued working into their 80s, 90s and beyond, Lithgow says, and usually these jobs are in environments where they interact with younger people.

Interacting with other generations can keep older people engaged, and some retirement communities and nursing facilities are now taking steps to give their residents opportunities to connect with kids - for instance, placing kindergarten classrooms in nursing homes.

Most of the proven tips for living a long, healthy life are not products that you buy, but good lifestyle habits that you adopt (or bad ones, such as smoking, that you either quit or never take up and are clearly associated with diminished longevity).

Even something as simple as always wearing a seat belt can reduce your chances of dying early. Most of the things that make up a longevity lifestyle are simple - exercise, eat (and drink) healthily, sleep adequately, stay engaged - if only people would do them.

"To me, the bottom line is: Live a reasonably moderate life and you'll be OK," Carstensen says.

Washington Post

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Push-ups? Here's what can really help you live to a ripe old age - The Australian Financial Review