Mark Patrick Taylor, Macquarie University and Scott P. Wilson, Macquarie University

A recent study published in the prestigious New England Journal of Medicine has linked microplastics with risk to human health.

The study involved patients in Italy who had a condition called carotid artery plaque, where plaque builds up in arteries, potentially blocking blood flow. The researchers analysed plaque specimens from these patients.

They found those with carotid artery plaque who had microplastics and nanoplastics in their plaque had a higher risk of heart attack, stroke, or death (compared with carotid artery plaque patients who didn’t have any micro- or nanoplastics detected in their plaque specimens).

Importantly, the researchers didn’t find the micro- and nanoplastics caused the higher risk, only that it was correlated with it.

So, what are we to make of the new findings? And how does it fit with the broader evidence about microplastics in our environment and our bodies?

What are microplastics?

Microplastics are plastic particles less than five millimetres across. Nanoplastics are less than one micron in size (1,000 microns is equal to one millimetre). The precise size classifications are still a matter of debate.

Microplastics and nanoplastics are created when everyday products – including clothes, food and beverage packaging, home furnishings, plastic bags, toys and toiletries – degrade. Many personal care products contain microsplastics in the form of microbeads.

Plastic is also used widely in agriculture, and can degrade over time into microplastics and nanoplastics.

These particles are made up of common polymers such as polyethylene, polypropylene, polystyrene and polyvinyl chloride. The constituent chemical of polyvinyl chloride, vinyl chloride, is considered carcinogenic by the US Environmental Protection Agency.

Of course, the actual risk of harm depends on your level of exposure. As toxicologists are fond of saying, it’s the dose that makes the poison, so we need to be careful to not over-interpret emerging research.

A closer look at the study

This new study in the New England Journal of Medicine was a small cohort, initially comprising 304 patients. But only 257 completed the follow-up part of the study 34 months later.

The study had a number of limitations. The first is the findings related only to asymptomatic patients undergoing carotid endarterectomy (a procedure to remove carotid artery plaque). This means the findings might not be applicable to the wider population.

The authors also point out that while exposure to microplastics and nanoplastics has been likely increasing in recent decades, heart disease rates have been falling.

That said, the fact so many people in the study had detectable levels of microplastics in their body is notable. The researchers found detectable levels of polyethylene and polyvinyl chloride (two types of plastic) in excised carotid plaque from 58% and 12% of patients, respectively.

These patients were more likely to be younger men with diabetes or heart disease and a history of smoking. There was no substantive difference in where the patients lived.

Inflammation markers in plaque samples were more elevated in patients with detectable levels of microplastics and nanoplastics versus those without.

And, then there’s the headline finding: patients with microplastics and nanoplastics in their plaque had a higher risk of having what doctors call “a primary end point event” (non-fatal heart attack, non-fatal stroke, or death from any cause) than those who did not present with microplastics and nanoplastics in their plaque.

The authors of the study note their results “do not prove causality”.

However, it would be remiss not to be cautious. The history of environmental health is replete with examples of what were initially considered suspect chemicals that avoided proper regulation because of what the US National Research Council refers to as the “untested-chemical assumption”. This assumption arises where there is an absence of research demonstrating adverse effects, which obviates the requirement for regulatory action.

In general, more research is required to find out whether or not microplastics cause harm to human health. Until this evidence exists, we should adopt the precautionary principle; absence of evidence should not be taken as evidence of absence.

Global and local action

Exposure to microplastics in our home, work and outdoor environments is inevitable. Governments across the globe have started to acknowledge we must intervene.

The Global Plastics Treaty will be enacted by 175 nations from 2025. The treaty is designed, among other things, to limit microplastic exposure globally. Burdens are greatest especially in children and especially those in low-middle income nations.

In Australia, legislation ending single use plastics will help. So too will the increased rollout of container deposit schemes that include plastic bottles.

Microplastics pollution is an area that requires a collaborative approach between researchers, civil societies, industry and government. We believe the formation of a “microplastics national council” would help formulate and co-ordinate strategies to tackle this issue.

Little things matter. Small actions by individuals can also translate to significant overall environmental and human health benefits.

Choosing natural materials, fabrics, and utensils not made of plastic and disposing of waste thoughtfully and appropriately – including recycling wherever possible – is helpful.

Mark Patrick Taylor, Chief Environmental Scientist, EPA Victoria; Honorary Professor, School of Natural Sciences, Macquarie University and Scott P. Wilson, Research Director, Australian Microplastic Assessment Project (AUSMAP); Honorary Senior Research Fellow, School of Natural Sciences, Macquarie University

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

What do you imagine a good night’s sleep to be?

Often when people come into our sleep clinic seeking treatment, they share ideas about healthy sleep.

Many think when their head hits the pillow, they should fall into a deep and restorative sleep, and emerge after about eight hours feeling refreshed. They’re in good company – many Australians hold the same belief.

In reality, healthy sleep is cyclic across the night, as you move in and out of the different stages of sleep, often waking up several times. Some people remember one or more of these awakenings, others do not. Let’s consider what a healthy night’s sleep looks like.

Sleep cycles are a roller-coaster

As an adult, our sleep moves through different cycles and brief awakenings during the night. Sleep cycles last roughly 90 minutes each.

We typically start the night with lighter sleep, before moving into deeper sleep stages, and rising again into rapid eye movement (REM) sleep – the stage of sleep often linked to vivid dreaming.

If sleeping well, we get most of our deep sleep in the first half of the night, with REM sleep more common in the second half of the night.

Adults usually move through five or six sleep cycles in a night, and it is entirely normal to wake up briefly at the end of each one. That means we might be waking up five times during the night. This can increase with older age and still be healthy. If you’re not remembering these awakenings that’s OK – they can be quite brief.

What does getting a ‘good’ sleep actually mean?

You’ll often hear that adults need between seven and nine hours of sleep per night. But good sleep is about more than the number of hours – it’s also about the quality.

For most people, sleeping well means being able to fall asleep soon after getting into bed (within around 30 minutes), sleeping without waking up for long periods, and waking feeling rested and ready for the day.

You shouldn’t be feeling excessively sleepy during the day, especially if you’re regularly getting at least seven hours of refreshing sleep a night (this is a rough rule of thumb).

But are you noticing you’re feeling physically tired, needing to nap regularly and still not feeling refreshed? It may be worthwhile touching base with your general practitioner, as there a range of possible reasons.

Common issues

Sleep disorders are common. Up to 25% of adults have insomnia, a sleep disorder where it may be hard to fall or stay asleep, or you may wake earlier in the morning than you’d like.

Rates of common sleep disorders such as insomnia and sleep apnoea – where your breathing can partially or completely stop many times during the night – also increase with age, affecting 20% of early adults and 40% of people in middle age. There are effective treatments, so asking for help is important.

Beyond sleep disorders, our sleep can also be disrupted by chronic health conditions – such as pain – and by certain medications.

There can also be other reasons we’re not sleeping well. Some of us are woken by children, pets or traffic noise during the night. These “forced awakenings” mean we may find it harder to get up in the morning, take longer to leave bed and feel less satisfied with our sleep. For some people, night awakenings may have no clear cause.

A good way to tell if these awakenings are a problem for you is by thinking about how they affect you. When they cause feelings of frustration or worry, or are impacting how we feel and function during the day, it might be a sign to seek some help.

We also may struggle to get up in the morning. This could be for a range of reasons, including not sleeping long enough, going to bed or waking up at irregular times – or even your own internal clock, which can influence the time your body prefers to sleep.

If you’re regularly struggling to get up for work or family needs, it can be an indication you may need to seek help. Some of these factors can be explored with a sleep psychologist if they are causing concern.

Can my smart watch help?

It is important to remember sleep-tracking devices can vary in accuracy for looking at the different sleep stages. While they can give a rough estimate, they are not a perfect measure.

In-laboratory polysomnography, or PSG, is the best standard measure to examine your sleep stages. A PSG examines breathing, oxygen saturation, brain waves and heart rate during sleep.

Rather than closely examining nightly data (including sleep stages) from a sleep tracker, it may be more helpful to look at the patterns of your sleep (bed and wake times) over time.

Understanding your sleep patterns may help identify and adjust behaviours that negatively impact your sleep, such as your bedtime routine and sleeping environment.

And if you find viewing your sleep data is making you feel worried about your sleep, this may not be useful for you. Most importantly, if you are concerned it is important to discuss it with your GP who can refer you to the appropriate specialist sleep health provider.

Amy Reynolds, Associate Professor in Clinical Sleep Health, Flinders University; Claire Dunbar, Research Associate, Sleep Health, Flinders University; Gorica Micic, Postdoctoral Research Fellow, Clinical Psychologist, Flinders University; Hannah Scott, Research Fellow in Sleep Health, Flinders University, and Nicole Lovato, Associate Professor, Adelaide Institute for Sleep Health, Flinders University

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