What does it take to live longer? Less than you might think

To make a significant impact on our health or lifespan, we need to make significant changes. Right?

Not according to new University of Sydney research published in BMC Medicine.

Behaviour change can be daunting, but small tweaks can make a significant difference. Credit: Getty Images

Most of us understand that many cancers and most diabetes could be avoided if people did not smoke, moderated alcohol consumption, ate less, and became physically active. But, for various reasons many people find behavioural change difficult. As few as 20 per cent of people stick to healthy behaviour change interventions over the long term.

“If you try to get an inactive person to meet the physical activity guidelines of about 25 minutes a day, behaviourally, it’s very, very hard,” says Professor Emmanuel Stamatakis, director of the Mackenzie Wearables Research Hub at the Charles Perkins Centre.

Instead of a big change in one area, Stamatakis and his colleagues wondered if smaller tweaks across several health behaviours might be easier to maintain and have a greater impact.

“How can we put together interventions that have a good chance of being adhered to and are behaviourally sustainable?” he wondered.

Wearables and technology have opened up what was once a siloed industry, where researchers tackled diet, physical activity or sleep individually but rarely in combination.

That is despite the three lifestyle behaviours being intertwined.

They also have a knock-on effect. When we are sleep-deprived, we’re less likely to exercise because we’re tired. On the flipside, exercise can help us sleep better. Poor sleep affects our hunger hormones, dialling up our appetite and dialling down our body’s signals that we are full. And poor diet can, conversely, lead to a bad night’s sleep by disrupting the neurotransmitters that control our circadian rhythm.

So, for the new study, Stamatakis and his team analysed the sleep, nutrition and physical activity data from UK Biobank that tracked more than 59,000 participants over eight years.

Participants wore a device for one week, which captured their sleep and physical activity. They were also given a diet quality score (DQS) based on questionnaires about their intake of vegetables, fruits, fish, dairy, whole grains, vegetable oils, refined grains, processed and unprocessed meats, and sugary beverages.

On average, they found the risk of premature death was reduced by at least 10 per cent if people slept for 15 minutes more a day, plus did an additional 1.6 minutes of moderate-to-vigorous physical activity (MVPA) a day, and also ate an additional one and a half pieces of fruit or half a serving of vegetables a day – the equivalent of a quarter of a cup of cooked green vegetables such as broccoli, spinach, carrots, pumpkin or cooked dried or canned beans, peas or lentils.

This is the first study to examine the minimum – and hence likely more behaviourally sustainable – improvements across all three behaviours required for measurable improvements in health outcomes.

When separated out, the study found that achieving the same risk reduction by focusing on just one aspect would require significantly more effort. That is, 60 per cent more sleep or 25 per cent more physical activity. Just focusing on diet in isolation would not achieve a 10 per cent lower mortality rate. It also increases the chances of participants abandoning their efforts.

“People tend to think they have to make massive changes, and they go very hard at it and then give up,” says Jon Buckley, executive dean of the Allied Health and Human Performance Academic Unit at the University of South Australia. “This study is reinforcing that if people can make small changes, it can have a big effect on their health.”

Buckley adds: “You don’t have to become an elite athlete, have a pristine diet or perfect sleep.”

For people whose sleep, physical activity and diet were poor, combined increases of 75 minutes a day of sleep, 12.5 minutes a day of moderate to vigorous physical activity and a 25-point improvement in diet (five points equating to one less serving of processed meat a week, or an extra half serving of vegetables or a piece and a half of fruit) halved their all-cause mortality risk.

“The take-home message is: relatively easy and modest improvements in these three components result in vast improvement in length of life,” says Professor Rob Newton of Edith Cowan University.

Those with the optimal combination of behaviours – seven to eight hours of sleep a night, between 42 and 102 minutes of MVPA a day and a good diet score – do not get the 10 per cent reduction in premature mortality risk for the same tweaks. However, those good behaviours alone corresponded to a 64 per cent lower risk for all-cause mortality compared with the least healthy group.

While this part of the study looked at lifespan, the next will look at health span.

Stamatakis encourages people to take it one step at a time when faced with health challenges they meet while they’re trying to improve their lifestyle.

“Every little bit helps when it comes to health behaviours: every extra bit of fruit, every extra serving of vegetables, every extra minute of moderate and vigorous activity,” he says.

“Try to make little, gradual changes towards your goals. This study and other studies point in exactly the same direction. There are large effects from subtle changes.”

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