Since the federal government announced earlier this year it would scrap the higher private health insurance rebate for people aged 65 and over, opponents have come out in force.

Private Healthcare Australia, the insurers’ peak body, says the government’s own modelling of about 44,000 older Australians dropping their cover due to the resulting higher premiums is a “significant underestimate”.

Three state health ministers have warned the change would push more people into their strained public hospitals.

So how many people would really drop their cover as a result of this policy change?

Our new research, designed specifically to test this question, gives some clues. In a nutshell, the sky won’t fall in.

What will happen? Who says what?

Right now, the private health insurance rebate depends on both income and age. Someone 65 or over gets a bigger government rebate on their premium than someone under 65 on the same income. This rebate increases further for those aged 70 and over.

From April 2027, the government proposes removing that age-based bonus. So the rebate would be equal for everyone on the same income, regardless of age.

The government argues this fixes a subsidy that’s inequitable and poorly targeted, so will improve intergenerational equity.

Its own modelling predicts the vast majority of affected policyholders – about 99% – would keep their cover. This means about 44,000 would drop it.

This agrees with our earlier research showing most older Australians don’t need a bigger rebate to keep their insurance.

But last week, Private Healthcare Australia released polling of more than 1,500 people showing 39% of insured older Australians say they’d be more likely to drop their cover.

Based on the number of privately insured Australians aged 65 and over, that would mean about one million people, considerably more than the government’s predictions.

What did we find?

Our new research looks at the impacts of the government’s proposal. We used a decade of tax data taking into account how the rebate had shifted over time.

What makes our research unique is that we separated out the impact of Australia’s two big private health insurance levers – the rebate and the Medicare Levy Surcharge tax penalty. That means we could focus on the impact of scrapping the extra health insurance rebates for the over 65s without muddying the waters.

We estimated 14,821–42,498 older Australians would drop their cover. The range depends on how we sampled the data and accounts for uncertainty in our modelling.

Our upper figure is roughly in line with the government’s own modelling of about 44,000 older Australians dropping their cover.

We also looked at how much the policy would save the government. We put savings at roughly A$730–940 million a year by 2028–29.

So despite the modest drop in coverage, the fiscal saving is large. And our research explains why.

The rebate is poorly targeted. Most people over 65 getting the rebate would keep their cover with or without it.

How about the health industry’s claims?

So why does the health insurance industry say 39% would be more likely to drop their cover while the government’s modelling predicts roughly a 1% decline?

Stating hypothetical intentions in polls can be a poor guide to real behaviour.

Consider what happened more than a decade ago when the government proposed means-testing the private health insurance rebate. Similar industry polling predicted 1.6 million people would drop their cover. In reality, participation actually went up slightly.

One thing the polling and modelling agree on is who is affected. Both the government’s own figures and our published research show people on the lowest incomes are most likely to drop their cover.

The government’s modelling puts about 95% of the projected decline in the lowest income tier.

Private Healthcare Australia’s polling, once you look past the 39% headline, shows the same pattern: lower-income households are the ones saying they’d reconsider.

So people on low incomes may need more targeted support to maintain their cover. That may mean more targeted means-testing for the rebate down the track.

How about hospitals?

New South Wales, Queensland and Tasmania’s health ministers have warned the proposed change would push more patients into an already-strained public system. Such concerns are valid.

However, our earlier research found that changes in rates of private insurance coverage have only small effects on public hospital wait times.

Compared with the public sector’s 7.7 million hospitalisations in 2024–25, the potentially 44,000 more people shifting to public hospitals is small fry.

Take-home message

Our research verifies the government’s own modelling using different datasets and methods. Polling measures intentions rather than outcomes, so the 39% headline is likely to overstate what actually happens.

The evidence says this reform won’t cause a mass exodus from private health insurance, and definitely won’t overwhelm public hospitals as some states predict.

Yuting Zhang, Professor of Health Economics, The University of Melbourne; Kevin Staub, Associate Professor in Economics, The University of Melbourne, and Nathan Kettlewell, Associate Professor, School of Economics and Marketing, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

While most runners are chasing after a new goal or a personal best, some are chasing after something slightly more elusive: a runner’s high.

Some describe it as euphoria. Others as calm, clarity or even a sense of being completely absorbed in the moment. Many people experience some version of it after a long run or a spin class.

For years, scientists believed the phenomenon was caused by endorphins, the body’s natural opioids. But more recent neuroscientific research now indicates that this might not wholly be the case.

Instead, a runner’s high appears to emerge from several brain systems working together. This explains why a runner’s high has so many far-reaching effects – and why these effects can often persist long after the initial experience of euphoria.

The brain’s own cannabis system

Endorphins are naturally-occurring brain chemicals which are released during periods of physical stress help to reduce pain.

Aerobic exercise increases circulating endorphins. Numerous studies have demonstrated higher levels of the endorphin beta-endorphin following prolonged aerobic exercise, such as running. This is why endorphins were long believed to be the sole cause of a runner’s high.

But there’s a key problem with the endorphin theory. This is because endorphins circulating in the blood struggle to cross the blood-brain barrier – the tightly regulated system that protects the brain from substances in the bloodstream.

So while endorphins may well contribute to pain relief elsewhere in the body, they cannot fully explain the feelings of euphoria and emotional wellbeing generated by a runner’s high within the brain itself.

So scientists began searching for another explanation.

The breakthrough came with the discovery that exercise also activates the endocannabinoid system.

Endocannabinoids are naturally produced by our bodies. They help with functions such as pleasure, memory and stress regulation.

One of the most important chemicals produced by the endocannabinoid system is anandamide, one of the brain’s natural “feel-good” chemicals. It helps to reduce anxiety, ease pain and create feelings of calm and wellbeing. And, unlike endorphins, anandamide crosses the blood-brain barrier with ease.

After a long bout of aerobic exercise, blood concentrations of anandamide rise substantially. Once inside the brain, it activates cannabinoid receptors in regions involved in emotion, motivation, reward and pain perception.

The resulting effects are remarkably similar to many features of the runner’s high – including reduced anxiety, better movement, less pain and feelings of calm.

This isn’t to suggest that endorphins play no role in a runner’s high. Modern neuroscience suggests endorphins and endocannabinoids work together – with endocannabinoids probably playing the larger role in producing the emotional aspects of the experience.

Several other neurotransmitters also play a part in a runner’s high.

Dopamine, which is central to motivation and reward, helps reinforce actions that are beneficial for survival. Rather than simply producing pleasure, dopamine encourages us to repeat a behaviour that the brain considers valuable.

Serotonin contributes to emotional stability and wellbeing, while noradrenaline enhances alertness and focus.

Exercise also stimulates the production of brain-derived neurotrophic factor (BDNF), which supports the growth of new and existing brain connections and plays a vital role in learning and memory

Although BDNF probably doesn’t produce the immediate euphoria associated with runner’s high, it may help explain why regular running can improve various aspects of wellbeing.

The benefits of a runner’s high

A runner’s high is about far more than pleasure chemicals.

Running changes how different brain networks communicate. During prolonged, rhythmic exercise (such as running), activity within the default mode network – the collection of brain regions associated with self-reflection, worry and thinking – appears to decrease.

At the same time, brain regions involved in attention, movement and sensory processing become more coordinated. This shift may help explain why running often produces feelings of mental clarity or being completely immersed in the present moment.

For many people, the mental benefits of a runner’s high even outlast the run itself.

Exercise influences stress regulation, inflammation, neuroplasticity (the brain’s ability to adapt and change), sleep quality and emotional processing. This combination of benefits is something which few medical interventions achieve.

Importantly, scientists are increasingly recognising that the mental health benefits of exercise extend well beyond the runner’s high itself. Even people who never experience the euphoria of a runner’s high still show meaningful improvements in mood, cognition and resilience with regular physical activity.

But for those who still want to chase after a runner’s high, research suggests there’s a sweet spot to achieving it – and it doesn’t require long-distance, extreme endurance.

Most studies report increases in endocannabinoids after approximately 30 to 60 minutes of continuous aerobic exercise performed at moderate to vigorous intensity – so roughly 70-85% of maximum heart rate. The key is that the physiological stress is high enough to trigger these neurochemical responses without overwhelming the body.

That said, there is considerable individual variation. Although one survey found that around two-thirds of recreational runners had experienced a runner’s high at least once, it didn’t necessarily happen on every run.

Some people also appear naturally more responsive to exercise-induced endocannabinoid release. Genetics, sex, fitness level, sleep quality, psychological state and even expectations may all influence whether someone experiences runner’s high on any given day, too.

Laura Elin Pigott, Senior Lecturer in Neurosciences and Neurorehabilitation, Course Leader in the College of Health and Life Sciences, London South Bank University

This article is republished from The Conversation under a Creative Commons license. Read the original article.