We’d all like to live longer; at least, I would. But what about enjoying the time we have while we’re here and living healthier?

Over the past century, human life expectancy has dramatically increased for a variety of reasons. Chief among these are our advances in sanitation, public health, nutrition and medicine that have reduced mortality, especially in young people. As a result, many more people are able to reach older age.

According to Statistics Canada, in 2021, Canadians had a life expectancy of 81.6 years, which is a astonishing increase of 24.5 years since 1921. By the year 2050, it is projected that the number of people aged 85 years and older will triple.

The extension of life expectancy in the 20th century and beyond is one of humanity’s greatest achievements. However, it is crucial to draw a distinction between lifespan — the amount of time between birth and death — and healthspan, which is the amount of time during which a person is healthy within their lifespan. Older people are spending more time in poor health, and this represents a major individual and public health burden.

At an advanced age, the ability to maintain an independent lifestyle largely defines a person’s quality of life. As such, it’s not enough to merely extend life without a sufficiently long healthspan to accompany it. Our goals should therefore be to bring lifespan and healthspan as close together as possible.

The idea of extending healthspan is important because it challenges the idea that age-associated diseases are inevitable and can’t be mitigated or ablated.

Why muscle is important for extending healthspan

Beginning at around the fifth decade of life, muscle mass is lost at a rate of about one per cent per year, and strength at about three per cent per year. Exercise and optimal nutrition are two of our most important countermeasures against this.© (Shutterstock)

One major health challenge in the aging population is the decline in muscle mass, strength and function (otherwise known as sarcopenia), which can lead to functional impairment, loss of autonomy, metabolic disease and a greater risk of falls and fractures.

Alongside its role in posture and locomotion, muscle is a major contributor to resting metabolism, serving as an important reservoir of glucose (sugar) and lipids (fats). It also represents an important “buffer” of amino acids during periods of catabolic stress, such as that seen in critical illness. Markers of muscle health on admission to intensive care units are predictive of important outcomes like the number of ventilator-free days and mortality, and being older compounds this risk.

Beginning at around the fifth decade of life, muscle mass is lost at a rate of about one per cent per year, and strength at about three per cent per year. These reductions in mass and strength are typically interspersed with periods of muscle disuse (hospitalization and/or illness, for example) that accelerate losses in muscle mass and strength.

Even a relative reduction in walking activity (measured by a decline in daily step count) for as little as two or three weeks can bring about negative changes in body composition, reduced muscle strength and quality, anabolic resistance (an impaired ability to use dietary protein for muscle building), and disrupted blood glucose control in older people.

Given the fundamental role of muscle tissue in metabolic and general health, the maintenance of adequate muscle mass and quality has particular relevance for extending healthspan.

Skeletal muscle tissue is highly plastic: it remodels in accordance with the physical stresses placed upon it. It grows (termed “hypertrophy”) in response to the application of external loads and is rapidly lost (termed “atrophy”) when these loads are withdrawn — if you’ve ever had your arm or leg in a cast, you know what I mean. The good news is that we can leverage the plasticity of muscle tissue to our advantage.

In kinesiology professor Stuart Phillips’s research group at McMaster University, we study the impact of exercise and nutrition on human skeletal muscle health, with a particular interest in aging.

The lab’s work has shown that resistance exercise (strength training), even when performed sporadically and with lighter loads, can be an effective strategy to offset muscle losses during periods of reduced activity and disuse in older people. What’s more, this type of training can enhance the sensitivity of muscle tissue to dietary protein and help overcome anabolic resistance. It can also make your muscle more ready to take up glucose and reduce your risk of diseases like Type 2 diabetes.

Research now indicates that older people require more dietary protein (the source of “building blocks” for muscle) than the established guidelines suggest. Recent work from our lab has shown that higher-quality protein sources can improve muscle growth in older people. The optimal strategy appears to be consuming 1.2 – 1.6 grams per kilogram of body weight of protein daily (50 to 100 per cent greater than what is currently recommended), from a mixture of animal (e.g., meat, fish, dairy) and plant-based (e.g., legumes) sources.

No matter what age you start, you can build the metabolic equivalent of a retirement savings plan by repeatedly engaging in physical exercise and consuming adequate high-quality protein. In doing so, you can effectively close the gap between healthspan and lifespan, maintain independence and maximize quality of life in older age.

Matthew Lees is supported by a Canadian Institutes of Health Research (CIHR) Postdoctoral Fellowship award (Funding Reference Number 187773).

At the turn of the 20th Century, one could expect to live until 47 in the U.S. Now, medical advancements, like vaccines and antibiotics, and public health initiatives have increased life expectancy in the U.S. to 77 years old and 73 globally. 

While health conditions and systemic barriers like socioeconomic inequities and environmental conditions play a role in how long you live, researchers are finding that through individual lifestyle modifications and precision medicine, there are ways to counter the mechanisms behind aging to potentially help people live even longer and healthier. 

“Healthy longevity medicine is not science fiction anymore,” Dr. Andrea Maier, a professor in medicine and functional aging at the National University of Singapore and the founding president of the Healthy Longevity Medicine Society, told Fortune at the Longevity Investors Conference in Gstaad, Switzerland last month. “We understand why we age. We understand, especially through life interventions, how to intervene.” 

The idea that we play a role in how well we age has led to a proliferation of biohackers or longevity optimists confident they will live to 150—and even beyond—because they are willing to experiment with the latest interventions to optimize health. Kayla Barnes, CEO of LYV Wellness, an LA-based longevity clinic, previously told Fortune she hopes to live 150 healthy years alongside her husband. At the same time, the entrepreneur turned biohacker Bryan Johnson doesn’t have a goal age but is preaching his motto “Don’t die” for as long as possible. 

But how long will it really be possible to live, according to available science? 

How long can we expect to live? 

Those under 50, who will have the most time to take advantage of emerging research, therapeutics, and interventions, can likely expect to live up to 100, says Dr. Evelyne Bischof, an internal medicine physician, oncologist, and vice president of the Healthy Longevity Medicine Society. 

Alina Su, an aging researcher at The Conboy Laboratory at UC Berkeley and a biomedical PhD candidate at Harvard, is even more hopeful. 

“Living well beyond 100—potentially up to 120 or more—isn’t just a dream. It can be a reality for those who are serious about optimizing their health,” says Su, cofounder of Generation Lab, a precision medicine company. “With the rapid pace of innovation in anti-aging research, we’re seeing new therapies, gene editing, personalized medicine, and other things that will push the upper limits of human lifespan.”

The world’s leading geneticist, Dr. Nir Barzilai, who is the director of the Institute for Aging Research at the Albert Einstein College of Medicine, tells Fortune that while he cannot predict society’s potential longevity, the maximum human life span is around 115 years today (the woman thought to be the oldest person in the world died at 122 in 1997). Barzilai says how much longer we can live depends on the efficacy of the evolving aging research coming to light in the next few decades. 

“Aging drives age-related disease. Therefore, you want to stop aging, and so we want to spend our time treating our health, rather than spend our time treating a disease,” says Barzilai, who also holds titles as a board member at the American Federation for Aging Research (AFAR) and investigator of the AFAR SuperAgers Family Study. “We know we can target aging … depends how fast funding can accelerate it.” He emphasizes that educating the public on ways to intervene will make a difference in meaningfully extending liTo live past 100 today, Barzilai says it’s about following basic guidelines around exercise, nutrition, and managing stress while also keeping an eye on the next frontier of longevity science—which he believes to be a combination of precision medicine, AI interventions, and gerotherapeutics or drugs to target the underlying processes of aging. 

Still, Barzilai, Bischof, and Maier, who are working to create standards in the field of longevity medicine, say it’s much more about how well you live than how long you live. 

“The question is, will they live up to 100 in good health, or will the last usually 20% see a significant decline in function?” says Bischof, who also spoke at the Longevity Investors Conference. Closing the healthspan-lifespan gap is the most imperative, she adds. 

The health optimizers 

Those who will substantially extend life and close the healthspan-lifespan gap will treat their body like a “top sport,” Maier says. “I really think that we should not treat our body as a snapshot, but a story and the story can only be written if you have more words, which means that you should test the body continuously,” she says, touting the growing field of precision geromedicine (therapeutics to tackle aging depending on a person’s biomarkers and genetic makeup), which requires testing and tracking to influence habits. The most common types of tracking include wearing a glucose monitor, sleep tracker, and activity monitor. 

Right now, partaking in the craze to extend life is reserved for those with the time and financial resources to pay out of pocket for additional testing, wearables, and subscription-based longevity clinics.

“For today's under-50 population, the key lies in how much they're willing to invest in their health now. The more proactive individuals are, the more years they're likely to add to their lives,” Su says. “In essence, we're entering an era where personal health choices could lead to dramatically different outcomes. The decision to optimize one's health today could mean the difference between a standard lifespan and an extended, vibrant life well past the century mark.” 

Dr. Matthew Pywell, who founded the Apex Medical Academy, which educates health professionals on preventative health care and healthy aging, says that while we know that it’s possible to hit that 120 mark as a species, the question will be how to deliver longevity interventions to the masses and not merely the 1%. 

Those at the forefront of longevity equity are looking to put healthy aging innovations into health care systems and meet people where they are—although it’s clear there is a long way to go to ensure that longevity medicine doesn’t exacerbate existing inequalities.  

“There are lots of private clinics. We now understand that we have to educate not only physicians but also all other healthcare professionals. We have to educate laymen and then really bring this new model of medicine into clinical care to really change the health trajectory [of more people],” Maier says.

Dr Jenna Macciochi says that ‘our immune system is the single greatest arbiter of both how long we live and the quality of those years’ - Christopher Pledger

We know what our immune system is about. It’s what fends off bugs and determines how long it takes us to recover from illnesses. We may have attempted to boost it by popping a multivitamin, eating an orange or even trying an overpriced ginger shot when we feel a cold brewing.But this narrow view barely scratches the surface of its wide-ranging impact not only on our health but also our longevity, says immunologist Dr Jenna Macciochi. “Our immune system is the single greatest arbiter of both how long we live and the quality of those years,” she writes.

At a time when longevity has become the latest obsession of millionaire tech bros (Bryan Johnson spends up to $2 million a year to extend his life expectancy through hit 40-a-day supplement habit, morning oxygen therapy and regular plasma transfusions from his teenage son), Dr Macciochi’s focus is on improving the simple things – mainly our diet and exercise levels – to harness the power of our immune system to keep us in better health for the 80 years we’re likely to live for.

“The longevity space has become dominated by male voices, ‘hack your way to the perfect protocol’, ‘20 things to do before you leave your house in the morning’,” she says. “I wanted to be the anti-Bryan Johnson.” There’s no evidence that living this way will extend your lifespan or make your latter years any healthier, Dr Macciochi notes.

Five common habits that age your brain revealed by doctor

And she would know – she’s a bona fide scientist. After growing up on a farm in rural Scotland, which kickstarted her fascination with health and disease, she studied immunology at the University of Glasgow before securing her PhD at Imperial College London. She went on to work for biotech companies and research institutes before lecturing at the University of Sussex. She is now a consultant and author based in Brighton, where she lives with her two children.

‘I’m trying to get people to stop just thinking about their immune system for colds and flus’: Immunologist Dr Jenna Macciochi

What is our immune system?

“Most people will be able to tell you where their digestive system is, where the brain is, where their lungs are,” Dr Macciochi notes.

The immune system, meanwhile, is a harder concept to grasp. It’s made up of hundreds of different types of cells and signalling molecules, controlled by around 8,000 genes – making it the second-most complicated system in our body, after our brains.

Rather than being in one place, it’s located throughout our bodies. Around 70 per cent of the immune system is found in our digestive tract while the rest ranges from the skin’s surface to our bone marrow, as well as from brain to big toe. “It’s a testament to how important it is,” she says.

How has it been misunderstood?

“I’m trying to get people to stop just thinking about their immune system for colds and flus,” Dr Macciochi says. Protecting us from bugs is one of its key roles, however. It’s why immune cells line the entry points to our bodies – the eyes, nose and mouth – which are coated in a defensive mucus that aims to catch viruses and bacteria before they can travel deeper into our bodies.

“We’ve always looked at the immune system through the lens of infection, which became less relevant in a country like the UK in the last 50 years because we have antibiotics, we have vaccines and we have public health measures that means we’re not dying from antibiotics, diphtheria and measles,” Dr Macciochi notes.

However, our immune system is also working in other ways to keep us well, Dr Macciochi notes. It monitors and eliminates potential cancer cells, protects against autoimmune disorders and manages our response to allergens.

It even plays a role in chronic diseases, as inflammation, which is triggered by the immune system, is thought to be a driving force in heart disease, diabetes, cancer and dementia, she notes.

How is our immune system linked with longevity?

The immune system is what has kept the human species alive for hundreds of thousands of years by triggering an inflammatory response when we become infected with a virus or bacteria. “It makes the body a hostile environment for a germ, so you can kill the germ and get rid of it,” Dr Macciochi explains.

However, this inflammatory response is being triggered too often as a result of our modern lifestyles that typically consists of a poor quality diet, frequent exposure to pollutants and mental stress, she says.

“It’s sending danger signals to our immune system but the danger isn’t a real danger and it’s not acute, it’s like constant, tiny hits,” Dr Macciochi says. The result is “inflammageing” which is the low-level, unwanted inflammation that builds up over time. “It’s like rust on a car” and fuels the onset of non-communicable diseases.

“Inflammation will happen anyway – there’ll be a gradual increase with age, just like everything wears out with time,” she notes. “I don’t think we can make ourselves invincible to that but we can definitely push back on this slow burn of chronic inflammation.”

Research into the hallmarks of ageing has shown that inflammation accelerates them all, Dr Macciochi says. “The telomeres on the end of our chromosomes, which are protective tips, inflammation accelerates wearing that down. The mitochondria in our cells, which are these little energy battery packs, the inflammation makes them less efficient.” It also contributes to DNA damage, which can drive the growth of cancer, she says.

“In all of these systems, inflammation puts this extra burden on top of them, so they have to work harder and then over time you get the wear and tear effect.”

Four habits to boost your immune system and increase your lifespan

“In the UK, we live on average to 80, which is amazing, compared to 150 years ago when you’d be lucky to get to 50,” Dr Macciochi says. “We’ve had an amazing longevity revolution already.”

However, the average Brit has a health span of 60, meaning there are “20 years where, medically, we can keep you alive and functioning but your quality of life might not be very good”, she says. “You might be on multiple medications and then medications to treat the side effects of those medications.”

While our body’s system will decline with age, unhealthy lifestyles preclude us from engaging in the activities that keep us young, she says. Setting up good habits that support our immune system now can elongate the number of years we spend free from illness – these are the habits Dr Macciochi recommends.

Do more exercise

One study found that regular exercisers live up to seven years longer, and have more years in good health - Halfpoint Images

It’s not news that exercise is good for us but its ability to improve immune health and life expectancy really are second to none, according to Dr Macciochi.

One study found that regular exercisers live up to seven years longer but also have more years in good health. “There are very few, if any, things medicine can offer that come anywhere close to that magnitude of benefit,” she notes.

Surprisingly, the benefits of exercise stems from the fact that it triggers inflammation – but the good kind. “I liken it to a dirty kitchen table,” Dr Macciochi says. “If I spill some coffee on it, and then I clean it, I’m going to end up with a table that’s cleaner than it was before I spilled the coffee. That’s how exercise works as an anti-inflammatory.”

“You exercise and get a rise in inflammation, but in a very controlled way that then gives this super rise in anti-inflammatory kind of clean-up, which doesn’t just clean up the muscles that you’ve been working in the gym but works across the whole body,” she says. “It’s one of the best anti-inflammatory tools we have.”

Exercise also keeps the thymus gland healthier for longer. This is located in our necks and produces T cells, which are the master controllers of the immune system, but its performance declines with age and it has deteriorated significantly by the age of 70, which is why older adults become more vulnerable to infections like pneumonia and shingles, Dr Macciochi says.

“There’s some lovely research showing that physical activity offsets that decline,” she says. “It’s not going to stop it, it will still have this change but it’s going to be happening much slower.”

Ideally, we should all be doing some cardiovascular exercise and resistance-based exercise, Dr Macciochi says but most people will benefit simply from breaking up long periods of sitting, she says.

“Don’t defer until the perfect week when you can get to the gym five times,” she says. “Take your baseline activity level and make an increment, make it sustainable and then build it up again.”

Eat fewer calories and stop snacking

Avoid eating between meals to let your body digest the food and return inflammation to baseline levels - Getty

“As a nation, we are eating almost all the time,” Dr Macciochi says. Research shows that people are in a “fed state” for 18 hours a day. “Our digestion was never designed to cope with this,” she says. In the time after eating a meal, our bodies need a break to digest the food and return postprandial (post-eating) inflammation to baseline levels, she explains.

“If you’re snacking from 7am to 9pm, your body is never getting that nice rhythm,” Dr Macciochi says. Unwanted inflammation will build up and contribute to inflammageing, she says.

Meanwhile, studies have shown that eating less – reducing calories by 20 to 30 per cent while still meeting all nutritional needs – reduces inflammatory markers and inflammageing, she notes. While this approach may be recommended for younger people, especially below the age of 40, Dr Macciochi advises older groups against calorie restriction, so that they don’t lose muscle mass.

However, people should focus on consolidating their food into three meals, she says. “Make those meals really nourishing to prevent grazing all the time because we know that’s really not helpful for inflammation.”

Add anti-inflammatory foods to your meals

A Mediterranean diet has an anti-inflammatory effect.

Olive oil is one of the most-researched anti-inflammatory food, Dr Macciochi says. “It contains oleocanthal which has a molecular structure similar to the well-known anti-inflammatory ibuprofen,” she notes.

“It’s thought that people in the Mediterranean are living so long and so well because they’re getting this tiny anti-inflammatory effect every day through the olive oil that they use,” Dr Macciochi says. “If people want to invest in a longevity supplement, I would say start with olive oil.”

The wider Mediterranean diet is made up of minimally processed grains, legumes, nuts, seeds, fresh seasonal produce, olive oil and oily fish, she notes. “These dietary patterns don’t just prevent chronic disease – they actively mitigate the mechanisms driving inflammageing,” according to Dr Macciochi.

Research also shows that adopting the MIND diet, made up of antioxidant-rich leafy greens, berries, wholegrain, nuts beans and fish, will reduce inflammation and protect against Alzheimer’s. “It has been designed to take elements that are good for brain health,” Dr Macciochi explains. “It’s high in polyphenols, antioxidants and it’s good for the gut and it’s anti-inflammatory.”

“People don’t make the link between cognitive function and inflammation but that’s a growing area,” she says. “If we have raised inflammation in the body, that will be affecting what happens in the brain. We have immune cells in the brain called microglia and when they sense danger, they start spitting out inflammation which we know is then linked to cognitive decline.”

Eat more fibre to improve gut health

High-fibre foods like carrots are key for good immune health - robynmac

“Around 70 per cent of our immune cells are located along the digestive tract,” Dr Macciochi notes. “The main reason for that is because the digestive tract is an obvious route for infection. We also have a collection of microbes that live in there and make up the microbiome.”

Our microbiome is essential for producing immune-modulating cells, such as T cells which prevent the immune system from overreacting to harmless substances or underperforming when we do encounter a bug, she explains.

Fibre is the forgotten key for good gut health and good immune health. “When your microbes break it down, they produce short-chain fatty acids which are anti-inflammatory,” Dr Macciochi says. “They keep the gut barrier really tight. They help seal up postprandial gut leakiness.

Vegetables, fruit and legumes are all rich sources of fibre but it’s important to increase how many you’re eating slowly to reduce the risk of uncomfortable bloating, she adds.