We are at a unique moment in history, a potential tipping point where our understanding of behavioural science and advances in technology are coming together powerfully to improve people’s lives.

The research institute RAND Europe has just published the largest behaviour change study on physical activity, based on verified data from health insurance company Vitality. There is one simple, profound finding: people can be incentivized to take more exercise.

The headline result was a sustained 34% increase in physical activity levels. That means people did one extra day of activity per week. At Vitality, we estimate that equates to two more years of life on average.

This has important implications for society. We are seeing huge growth in lifestyle diseases, and ageing populations are facing extra years of life that are made a misery by ill health. Significantly, while fewer of the participants most at risk changed their behaviour, those that did more than doubled their activity levels.

Physical inactivity is a classic behavioural problem. Its immediate costs, such as effort, time and pain, often trump its long-term benefits. So the Active Rewards programme, which is open to Vitality life and health insurance holders, creates short-term incentives for exercise which make it more likely people will participate. If you hit your weekly targets, you get rewarded, with a reduced or free Apple Watch, lower gym membership costs, free cinema tickets or coffee. Apple Watch acts both as an incentive and as a user-friendly, accurate way of measuring activity levels.

The study looked at more than 400,000 participants in the UK, US and South Africa, measuring completely anonymized demographic data, biometric information and tracking physical activity. The combination of Vitality’s short-term incentives programme and Apple Watch technology (contained in a specific benefit called Vitality Active Rewards with Apple Watch) creates meaningful beneficial behaviour change, regardless of age, gender and health status. In particular, at-risk participants, although less likely to participate, had far higher-than-average improvement in activity levels when they did.

The lessons of this study can be applied more widely by policy-makers, particularly those seeking to focus on the cost-effective prevention of disease rather than the much more expensive cure approach. Given that millions of us are going to live longer, the study also answers the questions of how we ensure those extra years are healthy, and how we can afford to pay for them.

We all know exercise is good for you; just 30 minutes a day of moderate exercise make a huge difference. But we underestimate just how important it is. One in four people worldwide are not active enough. Worse, 80% of adolescents aren’t. UK life expectancy is flatlining for the first time in a generation, partly as a result. Obesity is overtaking smoking as the number one cause of preventable cancer.

Advances in medical science mean that many of the diseases that killed our grandparents are no longer a major threat. Instead, it is the major non-communicable diseases - diabetes, heart disease and cancer - which are driving illness and death across the globe. These are also precisely the conditions where good choices regarding activity make a profound difference. About 10% of all early deaths globally are caused by physical inactivity.

The costs to society are significant. Recent research estimates the costs of physical inactivity at around 9% of total healthcare spend, rather than the 2-3% previously thought. The US Department of Health estimates the direct cost in America at $117 billion, so $500 billion dollars worldwide is a conservative estimate.

Human beings are often bad at making decisions about long-term health. Instant gratification (that slice of cake), short-term costs (time, effort, pain of exercise) and misplaced optimism (it probably won’t happen to me) mean many people make poor decisions that ultimately lead to bad health outcomes. Financial services often involve balancing short-term choices with long-term rewards, so the behavioural approach is particularly powerful.

The personal benefits of physical activity are powerful. As well as longer life, exercise improves the quality of that life, leading to fewer diseases and less disability. Physical activity reduces the risk of the major non-communicable diseases - cardiovascular disease, hypertension, diabetes, and breast and colon cancer. Physical activity also has positive effects on mental health, delays the onset of dementia, keeps your brain sharp and improves your sleep.

Vitality grew out of a particular context - post-apartheid South Africa, where there was a shortage of doctors, a high disease burden and changing regulation that required a new approach to help fund health insurance. We found that a shared-value model, where incentives drive better behaviour and where cost savings from this improved behaviour fund the incentives, had a dramatic impact on people’s choices.

The transformation is about actually reducing the risk pool, not just managing it, as traditional insurers do. Shrinking the risk pool creates an actuarial surplus, which we can then use to fund incentives and lower costs for customers. We estimate customers can reduce their lifetime healthcare costs by around 10%.

Prevention is far better than cure. With the right incentives in place, people can choose to be healthier. Now we need to make this a reality.