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  • Olivia Willis

There's a hack for living longer and it's hidden inside your cells

Updated: Jan 22, 2021

In the latest episode of Catalyst, former ABC journalist Ian Henderson discovers research that promises to keep us all younger for longer.

The anti-ageing industry is worth millions of dollars. But ageing well doesn't have to involve pills or expensive gimmicks. A much cheaper (and more evidence-based) way to add years to your life is to understand how the cells in your body work — and keep them working well. At the heart of the ageing process is slow, molecular damage to DNA that accumulates over time and causes cells to become dysfunctional. One hypothesis proposes that ageing is, in part, caused by "survival and maintenance pathways" switching off after our reproductive years are over. If this is true, then by targeting the pathways involved in that switch, and turning them back on again, you might be able to keep your cells healthy for longer and ultimately extend your lifespan. So how do you flick the switch? A quick lesson in cell biology

First, imagine your cells as mini speedboats. (Stay with me.) "Our cells have two modes: one is the growth, speed mode and the other is the maintenance, longevity mode," says Luigi Fontana, an expert in healthy ageing at the University of Sydney.

Just like boats in speed mode, cells in growth mode consume a lot of energy; they also produce a lot of waste products and wear and tear, accumulating damage and ageing us at high speed. All of this energy is useful when, as a species, we want to grow and reproduce. The trouble is if we stay in growth mode for too long after our reproductive prime, we're more likely to experience poor health — and age faster than we should. "By changing the switch [to maintenance mode] … we can reduce pollution to our cells and keep our cells healthier and younger," Professor Fontana says. In maintenance mode, our cells produce fewer waste products and clean themselves up more efficiently. Cell growth and cell division slows, and the body becomes better at repair. "[The cells] are using the energy to activate pathways that are protecting against DNA damage, so [that means] less mutations, more capacity to get rid of the garbage within our cells, more antioxidant pathways, less tumours, less ageing," Professor Fontana says. "We have signalling pathways within our cells that are able to shift [our cells] from one mode to the other mode." There are multiple signalling pathways thought to trigger maintenance mechanisms in our cells. Calorie restriction kicks us into preservation

Professor Fontana's research looks at the role of food — and what happens when we eat less of it. "Diet, based on what we know from the research, is the most powerful intervention," he says. The idea that calorie restriction forces our body into maintenance mode has its roots in evolution. During times of scarcity or extreme environmental conditions, our bodies must adapt. When food is limited, we're forced to break down our fat stores for energy, instead of breaking down nutrients from food. This flicks on maintenance mechanisms in our cells. Professor Fontana has been credited with conducting the foundational research that gave rise to the hugely popular 5:2 diet, which advocates for intermittent fasting — for two, non-consecutive days per week — and then eating a usual diet the other five days.

On the fasting days, women limit their total intake to 500 calories and men to 600 calories, which is about 25 per cent of the recommended intake for normal weight adults. On the feasting days, they can eat normally and don't have to think about restricting calories. "With one or two days of fasting per week, you are rejuvenating the cells and the body," Professor Fontana says. While there is evidence that calorie restriction can improve the biomarkers of ageing in animals such as lower blood pressure and improved insulin sensitivity, there is limited evidence so far that it can influence the biology of ageing in humans. "My data are suggesting that probably 90 per cent of cardiovascular diseases are preventable, because if you have the right diet and exercise, you can keep these parameters very low and healthy," Professor Fontana says. It's important to note, however, that there's good evidence reducing your calories isn't a good idea at certain times in life, particularly when you're old, or young and still growing. Exercise adds years to your life

Keeping our cells healthy isn't just about what we eat — it's also how we move. As we age, we can lose as much as 15 per cent of our total muscle mass. There's a chance loss of bone density, mobility and frailty could be part of the picture. This happens for a number of reasons, from hormonal changes in our bodies to increased inactivity. So how can we combat this decline? "Being physically active and engaging with exercise is absolutely fundamental," says Corinne Caillaud, an exercise physiologist from the University of Sydney. "If you are over 40 years and if you engage in 2.5 hours of moderate physical activity a week, then you can get up to 3.4 extra years of life." Moderate intensity exercise should raise your heart rate to about 55 to 70 per cent of your maximum heart rate. But research has shown that pushing yourself even harder pays off. A study of over 650,000 adults over 40 in the US found those who did twice the recommended amount — 30 minutes a day of moderate exercise — gained approximately 4.2 years to their life. High intensity interval training

One way of turning up the dial on your exercise regime is with high intensity interval training (HIIT). Despite its reputation, HIIT isn't just for the young and healthy. It has benefits for people over 65, with research showing it can reverse some of the age-related deterioration of muscle cells.

"As we get older, we find we can't do the volume of training we used to do," says Peter Crombie, a nine-time world sprinting champion. "We have to cut it down to half or maybe the third of what we used to do. So, to achieve that, I've found that it's better to do high-quality work with short recoveries using HIIT." HIIT involves repeated short sessions of high-intensity physical activity, from six seconds to four minutes, with rests from 30 seconds to four minutes in-between. It means short bursts of energy to raise your heart rate, followed by periods of low intensity to bring your pulse back down again. "The benefits are directly related to the effort," Mr Crombie says. In addition to pumping blood around your body and increasing the flow of oxygen to your muscle cells, the intense bouts of exercise also put your body through a brief moment of stress — in a good way. The amplified chemical reaction that happens inside your cells repairs and rejuvenates vital structures called mitochondria. These act like mini power plants in our cells: converting the food we eat into energy. But their ability to do this declines as we get older. Intense exercise (like HIIT) has been shown to help stop or even reverse this decline and help fight ageing. It is, however, important to note that pushing yourself to this intensity is not for everyone. And experts say that people with chronic conditions, and most middle and older-aged people, should only conduct HIIT with the supervision of a fitness professional.

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