Children living in green neighbourhoods are less likely to develop asthma



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Several studies have shown that spending time in nature is good for health. Now new research has looked specifically at asthma and found that living in green neighbourhoods protects children from developing the condition.
from http://www.shutterstock.com, CC BY-SA

Jeroen Douwes, Massey University and Geoffrey H. Donovan, United States Forest Service

Since the pioneering work of architecture professor Roger Ulrich, who found that patients with a view of a natural scene recovered more quickly from surgery, research has shown that exposure to the natural
environment is associated with a wide range of health benefits.

We have focused our work on asthma, and our research, published today, shows that children who live in greener neighbourhoods are less likely to develop it.

Not all greenness was equally effective, however. If a child was exposed to a broader range of plants, they were even less likely to get asthma. Exposure to landscapes with low plant diversity, such as gorse and exotic conifers, on the other hand, were a risk factor for asthma. Thus, greenness is good, but more biodiverse greenness is even better.




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How nature protects against asthma

One intriguing explanation is provided by the hygiene hypothesis, which proposes that for children’s immune systems to develop properly, they need to be exposed to a broad range of microbes in early life. Without this exposure, children may be more susceptible to immunological diseases, like allergies and asthma.

The hygiene hypothesis explains why children living on farms, where they are exposed to a wide range of animals, are less likely to develop asthma. However, it’s not only farm children who benefit from exposure to animals. Having a pet in the house can also help protect against asthma. Similarly, children with more siblings are less likely to be asthmatic.




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Living around a more diverse range of plants may also increase a child’s exposure to microbes. In fact, past studies have shown that people who live in more biodiverse areas have more diverse skin bacteria. Exposure to the natural environment may, therefore, improve our health by increasing the diversity of microbes living on our skin and in our gut.

This, in turn, may promote a healthy immune response and reduce the risk of allergies and asthma. Reduced stress and increased physical activity, associated with living close to green space, may be another reason for the observed protective effects.

Tracking children’s environment

This study used the Integrated Data Infrastructure (IDI), which is a large database of individual-level data maintained by Stats New Zealand. Currently, it contains 166 billion pieces of information on education, benefits, tax, families and households, health, justice and migration.

Using these data, we were able to track where children lived from birth until age 18, calculate the greenness of their neighbourhoods using satellite imagery and land-use data, and link to health records throughout each child’s life. This was all done anonymously, in a secure data lab, to safeguard the children’s privacy.

This study is an unusual collaboration between economists at the US Forest Service and epidemiologists in New Zealand. It contributes to our understanding of why asthma is on the rise.

Our results may lead to some innovative strategies to combat asthma, although there is a need to elucidate the underlying immunological mechanisms.

Improved prevention and treatment options for asthma are urgently needed as the burden of asthma is considerable, with 334 million people affected worldwide. Asthma prevalence in English-speaking countries such as New Zealand, Australia, the US and the UK is particularly high, with approximately one in six people suffering from it.

Good for people, good for the planet

Showing a link between biodiversity and human health may also change how we manage natural resources, especially in cities. Unfortunately, biodiversity is declining around the world due to population growth, climate change and intensive agricultural practices. Our work suggests that this is not just an ecological problem, but may also present a significant threat to public health.

The ConversationOther studies have suggested that the exposure to the natural environment also protects against low birth weight, heart disease, mental health disorders and breast cancer, although results have not always been consistent. Therefore, as the diversity of our natural environment and resultant microbial exposure declines, we may see further increases in diseases, such as childhood allergies and asthma.

Jeroen Douwes, Professor of Public Health; Director, Centre for Public Health Research, Massey University and Geoffrey H. Donovan, Economist, United States Forest Service

This article was originally published on The Conversation. Read the original article.

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Why we are measuring the health of Australian vegetation poorly



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The Victorian mountain ash forest has been severely affected by fires and logging. To determine the actual health of the forest, we need to look at the quality, not just the quantity of what remains.
Graeme/flickr, CC BY-NC

Ayesha Tulloch, University of Sydney; David Lindenmayer, Australian National University, and Hugh Possingham, The University of Queensland

Many of Australia’s ecosystems are in a much worse condition than we think. This is because officials are measuring the health of ecosystems such as forests and woodlands by their size, instead of how damaged they are by disturbances.

A “disturbance” is a short-term change in environmental conditions that leads to a long-term change in an ecosystem. Some habitat disturbances are natural, such as some fires and extreme weather events. Others are created by human activities, such as logging, pollution, intensive grazing, and mining.




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Frequent or intense disturbances generally pose a bigger threat to the health of an ecosystem and it’s not limited to the area of the ecosystem that is lost. This is because the quality of the vegetation that survives a disturbance, such as a fire, may be too low to support the animals that rely on it for food and shelter.

It is much easier simply to measure ecosystem extent rather than ecosystem condition. However, focusing on quantity instead of quality leads to less informed decisions about where and how to conserve native habitats and the wildlife that lives in it.

Disturbances to habitats

Disturbances have grown in frequency and variety. This is one of the major causes of habitat degradation.

Fires are a common and dangerous disturbance to many Australian habitats. The number of bushfires per week in Australia increased by 40% between 2008 and 2013. Increases in the frequency of fires due to human activity have led to the decline or extinction of more than 100 species and declines in at least 29 threatened ecological communities listed in Australia’s Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

Burnt and unburnt mallee heath in southwest Australia.
Ashley Pearce/Angela Sanders

More attention is now being paid to evaluating the risk of our ecosystems going extinct. But most of the attention is only on the area of vegetation that has been lost, which is easy to map and calculate thanks to images from satellites.

Measuring the disturbances

In a recent study, we found that some Australian ecosystems are more threatened than might be suggested by looking simply at vegetation loss.

We made this discovery by assessing “whole-of-ecosystem degradation”. This calculation is a two-step process. First, we observe the different ages of the vegetation, known as their “age classes”, in an area. Then, we compare how far the current distribution falls short of the ideal distribution of the group of plants that make up that vegetation community.

Some species (such as large trees) require long intervals between disturbances to allow them to have time to mature and reproduce, so their “ideal” age class distribution will have many old plants and fewer young plants. Other species (such as some fast-growing shrubs) prefer short intervals between disturbances, and their ideal age class distribution will have more young plants than old plants.

The “whole-of-ecosystem degradation” approach

We used this approach to look at the dominant plants and animals in two vegetation types: the protea-rich mallee-heath of southwestern Australia, and Victoria’s mountain ash forest.

Banksias are a key component of the ecosystem in the protea-rich mallee-heath forest.
from http://www.shutterstock.com

In the mallee-heath, the ideal distribution was based on the needs of Banksia species (which are in the Proteacea family). These plants provide critical nectar and pollen resources to many animals such as honey possums and honeyeaters. Many Banksias are long-lived and require up to 80 years between fires to maximise reproductive potential.

Our study showed that the banksia age-class distribution in this ecosystem is unbalanced, and therefore much poorer than indicated by information about just quantity. There are more young banksias (up to ten years old) and fewer older ones (more than 40 years old) than might otherwise be expected.

In simpler terms, the frequency of fire is clearly not able to support the flowering of banksia species, resulting in low habitat quality.

In the mountain ash (Eucalyptus regnans) forest, we used the food and shelter needs of the yellow-bellied glider (Petaurus australis) to assess forest health. This animal is already a threatened mammal.

Fire and logging have disturbed almost 50% of the forest in the last 30 years. Fires here are rare but of high intensity and severity, killing the trees in which these mammals live.

Again, our research shows that the remaining forest is in very poor condition. Compared to what would ideally be expected 120 years after a fire, the forest has more vegetation in very young (less than eight years old) and mid-age (up to 75 years old) age classes, and less vegetation in very old (more than 76 years old) age classes.

To sustain food sources and hollows for the yellow-bellied glider, the mountain ash would need to be protected from disturbance between 40 and 160 years.

The ideal time interval between fire disturbances to provide food and shelter to yellow-bellied gliders in mountain ash forest is more than 120 years, to allow new trees to grow after burning kills old trees. Photos show progression from newly burnt to old growth forest.
David Blair/Tabitha Boyer

Understanding the effect of disturbances

Our research shows that measuring an ecosystem’s health by its size alone can be misleading, especially when the area is large but severely degraded.

It is therefore crucial to consider disturbances when evaluating ecosystems. This is especially so when forest health is being assessed for listing through the IUCN Red List of Ecosystems, or for conservation planning and management.




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We recommend that decision-makers be more aware of the role of disturbances in degrading ecosystems. This requires two crucial elements of information.

First, we need good maps that tell us when the last disturbance in an area was. This kind of mapping is carried out within our protected reserve system, but is not currently available at a national scale.

Second, we need a better understanding of ideal benchmarks of ecosystems to compare with the current conditions. Benchmarks may be linked to the needs of dominant plant species (such as banksia in mallee-heath) or the needs of dependent species of concern (such as yellow-bellied glider in mountain ash).

The ConversationWe propose that our method be applied to evaluate the condition of different ecosystems. This will ensure that ecosystem declines are identified before systems cannot be recovered.

Ayesha Tulloch, DECRA Research Fellow, University of Sydney; David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University, and Hugh Possingham, Professor, The University of Queensland

This article was originally published on The Conversation. Read the original article.

Why Australians need a national environment protection agency to safeguard their health


David Shearman, University of Adelaide

Australia needs an independent national agency charged with safeguarding the environment and delivering effective climate policy, according to a new campaign launched today by a coalition of environmental, legal and medical NGOs.

Most Western democracies have established national regulatory action, such as the US Environmental Protection Agency – yet Australia is a notable exception.

Today in Canberra, the Australian Panel of Experts on Environmental Law (APEEL) will hold a symposium on the reform of environmental laws in Australia. If enacted, these proposals would offer protection to Australia’s declining biodiversity and environment, as well as helping to safeguard Australians’ health.




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The proposal would involve establishing a high-level Commonwealth Environment Commission (CEC) that would be responsible for Commonwealth strategic environmental instruments, in much the same way that the Reserve Bank is in charge of economic levers such as interest rates.

The new CEC would manage a nationally coordinated system of environmental data collection, monitoring, auditing and reporting, the conduct of environmental inquiries of a strategic nature, and the provision of strategic advice to the Commonwealth government on environmental matters, either upon request or at its own initiative. The necessary outcomes would then be delivered by government and ministers via a newly created National Environmental Protection Authority (NEPA).

Tomorrow, this call will be echoed by a major alliance of leading environmental groups, including Doctors for the Environment Australia. Similar to the CEC/NEPA proposal, this group has called for an independent “National Sustainability Commission” that would develop conservation plans, monitor invasive species, and set nationally binding air pollution standards and climate adaptation plans.

The new body would replace the EPBC Act, which has failed to deliver the protections it promised in key areas such as land clearing and species protection, and has no role in limiting climate change which is a major factor in species loss.

The new agencies would be in a position to provide authoritative and understandable consensus reports, similar to those produced by the Intergovernmental Panel on Climate Change but with a stronger legal basis on which the government should act on its advice.

Why change the system?

The rationale for reform is clear. Only last week the International Energy Agency reported that Earth’s greenhouse emissions have increased yet again. Meanwhile, extreme weather events have increased, while wildlife diversity is on the decline.

Having failed so far to arrest these trends, the governments of countries with high standards of living and high greenhouse emissions should be held particularly accountable. Clearing land and burning forest for firewood are understandable survival strategies for the poor, but unacceptable in rich nations.

Australia’s national laws would be strengthened to address the challenge of climate change and ensure we can mitigate, adapt to and be resilient in the face of a warming world.

Action on climate change, essential to protect biodiversity, is also vital to protect human health as a quarter of world disease has its root causes in environmental change, degradation and pollution.

The World Health Organisation regards climate change as the greatest health threat of the 21st century, a view recognised by the statements of the Australian Medical Association and Doctors for the Environment Australia.

Already, it is responsible for thousands of deaths worldwide, and that figure is projected to rise to 250,000 by 2030. In Australia, air quality reform could prevent an estimated 3,000 air pollution deaths per year.

Causes of current inaction

There are fundamentally two causes of inaction. First, in this increasingly
complex world, governments now more than ever need impartial advice based on the best available evidence. Yet all too often, such advice is politicised, ignored, or both.

Second, in leading democracies – particularly in Australia with its relatively short election cycles – the pressure to focus on re-election prospects dictates that governments emphasise jobs, growth, and living standards. It takes strong leadership to promote the interests of future generations as well as current ones.

It seems counterintuitive to suggest that for its survival, a government might need to delegate decisions for human survival to systems beyond its immediate political control. Yet it already does delegate crucial decisions, such as the monthly interest rate calls made by the Reserve Bank.

A newly created CEC and NEPA would be charged with safeguarding the climate, wildlife, fresh water and clean air. It would be in a position to improve air quality to standards recommended by the World Health Organization, protect water quality, and deliver effective climate change mitigation and adaptation policy uniformly in all states.




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Around the world, environmental laws are under attack in all sorts of ways


The success of such a national system would manifest itself in a growing number of decisions similar to the recent rejection of the expansion of Stage 3 of the Acland coal mine. The judge in that case turned it down on the basis of a range of health and environmental transgressions, yet it is currently more common for states to approve this type of developments rather than reject them.

The ConversationNationally enforceable standards for resource developments are likely to bring effective preventative health benefits, as well as certainty of process. These reforms present an overdue opportunity for Australia to offer leadership and catch up on lost time, to ameliorate the progression of climate change and biodiversity loss, and thus lessen their future impacts.

David Shearman, Emeritus Professor of Medicine, University of Adelaide

This article was originally published on The Conversation. Read the original article.

Your asthma puffer is probably contributing to climate change, but there’s a better alternative



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There is an environmentally friendly option.
from http://www.shutterstock.com

Brett Montgomery, University of Western Australia

I breathe all the way out. There’s a quiet puff of gas from my inhaler, and I breathe all the way in. I hold my breath for a few seconds and the medicine is where it needs to be: in my lungs.

Many readers with asthma or other lung disease will recognise this ritual. But I suspect few will connect it with climate change. Until recently, neither did I.

In asthma, there is narrowing of the airways that carry air into and out of our lungs. The lining of the airways becomes swollen, muscles around the airways contract, and mucus is produced. All these changes make it hard to breathe out.

The most commonly used medicines in asthma are delivered by inhalation. Inhaling gets the medicines straight to the airways, speeding and maximising their local effects, and minimising side effects elsewhere compared to, say, swallowing tablets.

Some medicines (“relievers”) work quickly to relax the airway muscles. Others (“preventers”) work more slowly but do more good, preventing asthma’s swelling and inflammation of the airways.




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These medicines are available in various sorts of inhaler devices. The devices fall into two broad types: “metered dose inhalers” and “dry powder inhalers” of various shapes and sizes.

In metered dose inhalers, the medicine and a pressurised propellant liquid are mixed together in a little canister, and then sprayed out of the inhaler in a measured puff of fine mist. This is inhaled, often after passing through a “spacer” which allows more of the medicine to reach the lungs. While the medicine is absorbed by the body, the propellant, now a gas, is exhaled unchanged.

In dry powder inhalers, the medicine is in the form of a fine powder which is swept into the lungs as the user breathes in — there is no spray and no spacer.

Powder inhalers don’t release any gases at all.
Author provided

It’s feasible for many (but not all) people to use either sort of device. Young children do better with metered dose inhalers and spacers, as do people who struggle to inhale. But most asthmatics can inhale well from dry powder inhalers.

The two types of inhaler seem to work just as well as each other; if anything the dry powder ones might be a little better.

Metered dose inhalers are more often prescribed than dry powder devices in many countries, but this has more to do with history and familiarity than effectiveness.

What about those gases?

You might remember hearing, years ago, about “CFCs” — chlorofluorocarbons — and their dire effect on the ozone layer. A successful international treaty, the Montreal Protocol, led to their phase-out from various uses, including medical inhalers. And with that, I thought, the environmental problems of inhaler gases had ended.




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But CFCs were replaced with “HFCs” — hydrofluorocarbons — which are safe for the ozone layer, but which are potent global warming gases. HFCs are better known in their role as refrigerant gases in air conditioners and refrigerators.

A recent amendment to the Montreal Protocol has now planned a phase-out of HFCs, too, but it’s slow, with deadlines decades away. Earlier prudent management of these gases could make a big difference to climate change.

The one most often found in asthma metered dose inhalers, norflurane, is 1,430 times more potent than the best-known warming culprit, carbon dioxide. Another, apaflurane, is 3,220 times more potent than carbon dioxide.

Such warming power explains why even the small amounts in an inhaler are significant. Globally, tens of millions of tons of carbon dioxide equivalent are attributable annually to these inhaler gases.

How much pollution are inhaler gases responsible for in Australia? I wrote to several companies marketing asthma inhalers in Australia, asking them how much of these gases are present in their products. Some gave straight answers, but some hedged on grounds of commercial confidentiality. This makes it hard for me to be exact.

But based on some reasonable assumptions, and multiplying these by the number of inhalers dispensed on our Pharmaceutical Benefits Scheme last year, I tallied nearly 116,000 tonnes of carbon dioxide-equivalent pollution.

That’s equivalent to the emissions of about 25,000 cars annually. And this is surely an underestimate, as it doesn’t account for reliever inhalers sold over the counter. A person using a preventer inhaler monthly, plus the odd reliever inhaler, could easily release the annual equivalent of a quarter of a ton of carbon dioxide — that’s like burning 100 litres of petrol.




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How to change

The good news is, for many people with asthma, there’s an easy solution: shifting from metered dose inhalers to dry powder inhalers. As above, this won’t suit everyone, but will be possible for many.

I am both a doctor and a person with asthma. As an asthmatic, I’ve found changing inhalers to be easy — if anything, my dry powder inhalers are simpler to use. And as a doctor, I’ve been pleasantly surprised by how open my patients have been to this topic. I worried people might find it weird their GP was raising environmental issues at their appointment, but my fears were unfounded.

If you have asthma, a chat with your doctor or pharmacist would be a good way to gauge whether a dry powder inhaler is feasible for you. Don’t be surprised if they haven’t heard of this gas issue — awareness still seems limited.

The ConversationIf metered dose inhalers are a better choice for you, please don’t panic or quit your medicines. These gases probably won’t be the biggest contributor to your personal carbon footprint. Asthma control is really important, and these medicines work really well. But consider changing if it’s an option for you — when it comes to reducing our footprint, every little bit counts.

Brett Montgomery, Senior Lecturer in General Practice, University of Western Australia

This article was originally published on The Conversation. Read the original article.

I’ve always wondered: why many people in Asian countries wear masks, and whether they work


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Face masks are a common sight in Asia. Why?
David Chang/AAP

C Raina MacIntyre, UNSW and Abrar Ahmad Chughtai, UNSW

This is an article from I’ve Always Wondered, a series where readers send in questions they’d like an expert to answer. Send your question to alwayswondered@theconversation.edu.au


In Japan, many people wear face masks – is that to prevent the wearer getting the infection, or is the wearer already infected and protecting those around? Is the mask useful in protecting against viruses or bacteria? – Petrina, Greenwich

Thanks for your question, Petrina. You’re right, in countries like Japan and China, facemask use in the community is widespread – much more so than in Western cultures. People wear them to protect the respiratory tract from pollution and infection, and to prevent the spread of any pathogens they might be carrying.

Whether this works depends on the type of mask.

There are three supposed ways a mask can provide protection: by providing a physical barrier (which prevents splashes and sprays), by filtering the particles (blocking particles of a certain size from entering the respiratory tract), and by fitting around the face to prevent leakage of air around the sides.

Some mask makers have also gone the extra step of using antimicrobials and claim to kill bugs on the surface of the mask, but these haven’t been tested to see if they provide any benefit.

Healthcare workers have been using cloth masks (made of cotton or other materials and with ties to secure them at the back) while caring for patients since the late 19th century to protect from various respiratory infections such as diphtheria, scarlet fever, measles, pandemic influenza, pneumonic plague and tuberculosis.

Cloth masks have been around since the late 19th century.
Author provided



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During the mid 20th century, disposable surgical facemasks (similar in look to the cloth masks but made of paper) were developed. Surgical masks were developed to prevent the surgeon from contaminating the wound during surgery, but studies have not proven they help.

Surgical masks have no evidence of effectiveness.
from http://www.shutterstock.com

These were followed by respirators, which vary in shape and material but are designed to fit around the face and filter particles. Respirators are designed specifically to protect the respiratory tract from inhaled germs. There are many types, which may be reusable or disposable.

People must undergo fit-testing to ensure respirators are correctly fitted, with a good seal around the face. Unlike masks, respirators are subject to certification and regulation, and are proven to protect against respiratory infection.

Respirators are proven to protect against infection.
from http://www.shutterstock.com

Surgical masks are unregulated for filtration and do not fit around the face, and the evidence for their use is less convincing. In a community study, families with a sick child who wore such a mask were less likely to get sick if they also wore a mask, but many family members didn’t wear their masks all the time.

In a university setting, students were protected from sick classmates if they wore the mask within 36 hours of their classmate getting sick.

In many low income countries, the cost of even paper surgical masks is prohibitive, so cloth masks are used, washed and re-used. But these don’t protect against infection, and may even increase the risk of infection.

Prevention of infection vs source control

Masks can be used to protect healthy people (such as nurses and doctors) from exposure to infection, but are also used by sick people (such as a TB patient) to prevent spread of infections to others (called “source control”). There is less research on this use than on the use of masks by well people. The efficacy of source control is unknown.




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Do masks work?

It’s long been thought surgical masks protect from transmission of pathogens, which spread through the air on large, short-range droplets, while respirators protect against much smaller, airborne particles, which may remain suspended in the air for several hours and transmit infection over long distances. So most guidelines recommend a mask for droplet transmitting infections (such as influenza) and a respirator for airborne infections (such as TB and measles).

But we’ve shown respirators protect better than masks even against droplet-spread infections. And the longstanding belief that infections neatly fit into either droplet or airborne transmission is not correct. Respiratory transmission of infections is more complex than this.

To say whether masks work, we have to specify whether we’re talking about a respirator, a surgical mask or a cloth mask.

The respirators are the Rolls Royce option and do protect, and this is a tool for frontline health workers facing epidemics of known and unknown infections. Surgical masks probably also protect but to a lesser extent. But there’s no evidence cloth masks will protect against invading or escaping bugs.


The Conversation* Email your question to alwayswondered@theconversation.edu.au

* Tell us on Twitter by tagging @ConversationEDU with the hashtag #alwayswondered, or

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C Raina MacIntyre, Professor of Infectious Diseases Epidemiology, Head of the School of Public Health and Community Medicine, UNSW and Abrar Ahmad Chughtai, Epidemiologist, UNSW

This article was originally published on The Conversation. Read the original article.

Health Check: how can extreme heat lead to death?



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Our climate is going to get warmer, and we need to protect ourselves from heat-related illness.
from shutterstock.com

David Shearman, University of Adelaide

Our climate is becoming hotter. This is our reality. Extreme heat is already responsible for hundreds of deaths every year. It’s a big environmental killer, and deaths from heatwaves in Australian cities are expected to double in the next 40 years.

Those most at risk are the elderly, people with chronic illness, those living in socioeconomic disadvantage, outdoor workers, and athletes who play their sport in brutally high temperatures. But extreme heat can affect anyone at any age.

So, what happens in our body during times of extreme heat? And how can it lead to fatal consequences?




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How we lose and gain heat

Our core body temperature sits at around 37℃. If it rises or falls, a range of very efficient physiological mechanisms come into play. In good health, our body can usually cope well with deviations of about 3.5℃, but beyond that the body begins to show signs of distress.

In hot weather, the body maintains core temperature by losing heat in several ways. One is to transfer it to a cooler environment, such as surrounding air or water, through our skin. But if the surrounding temperature is the same or higher than the skin (greater than 35-37℃) the effectiveness of this mechanism is markedly reduced.

Blood vessels supplying blood to the skin dilate. This allows more warm blood to flow near the surface of the skin, where the heat can be lost to the air. That’s why some people’s skin looks redder in hot environments.

One way the body loses heat is by directly transferring it to a cooler environment.
from shutterstock.com

Evaporation (or sweat) is another way to lose heat from the body. If there is enough airflow and humidity is low enough, we can lose large amounts of heat through sweat. But on humid days, the rate of evaporation is reduced, as the air cannot absorb so much if it is already saturated with water vapour.

We can also reduce our heat production by resting. About 80% of the energy produced by working muscles is heat, so any activity will increase the amount of heat the body has to lose. This is why athletes and outdoor manual workers are at particular risk when performing at high levels of physical activity.




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What happens if the body can’t lose heat

Heat stress describes a spectrum of heat-related disorders that occur when the body fails to lose heat to maintain core temperature. Heat stress ranges from heat cramps to heat exhaustion (pale, sweating, dizzy and fainting). If the core temperature rises above 40.5℃, it can lead to heatstroke, which is a medical emergency, can occur suddenly and often kills.

The hypothalamus works as the body’s thermostat.
from shutterstock.com

Heatstroke is caused by a failure of the hypothalamus, the region of the brain that works as our thermostat and co-ordinates our physiological response to excessive heat. It’s what leads to mechanisms like sweating and rapid breathing, dilated veins and increased blood flow to the skin. So, when the hypothalamus fails, so does our ability to sweat and lose heat in other ways.

At temperatures higher than 41.5℃, convulsions are common. Irreversible brain damage can occur at temperatures above 42.5℃. Patients with heatstroke can show neurological signs such as lack of co-ordination, confusion, seizures and loss of consciousness.




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When sweating stops, the skin may become hot and dry, heart rate and breathing increase and blood pressure is low. Cells and nerves in the body become damaged. Liver damage is also common, but may not manifest for several days. The kidneys stop working, normal blood clotting is impaired, the heart muscle can be damaged and skeletal muscles start breaking down.

Essentially, this is what we describe as multi-organ failure. People with heatstroke can die within a few hours, or several days or even weeks later from organ failure.

Protecting yourself

Heatstroke could be “exertional”, as with athletes, or “classic”, which occurs in patients with impaired thermostatic responses, as a result of age, illness or medications.

Heatstroke can be caused by exertion, such as with athletes putting their body through stress in extreme temperatures.
from shutterstock.com

Much of the increase in deaths during hotter temperatures occurs in older patients with a chronic illness. This is because they may have a poorly functioning central nervous system that cannot orchestrate the physiological changes needed to lose heat.

Older hearts may not be able to cope with the changes in circulation needed for more blood flow to go to the skin. Some medications can also interfere with the mechanisms for heat loss.

People experiencing any of the warning signs of heat stress (headache, nausea, light-headedness and fatigue) need to alter their behaviour to reduce it.

The best way to do this is to find a cool spot indoors or in the shade, put on light clothing, avoid physical exertion, put a damp cloth on your skin, immerse yourself in cold water and stay well hydrated.

But for some people, like children who are too young to make changes to their environment (such as those left in cars), this is not possible. Also, for the elderly, perhaps those with chronic mental illness or on certain medications that impair their ability to respond to increasing core temperature, these signs may not be apparent or noticed.




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Strategies for coping with extremely hot weather


This means we need safeguards to ensure the vulnerable stay cool. This is especially a problem for elderly people who live alone.

So, as our climate warms up, we need to do all we can to minimise the consequences of an increasingly hot environment. That means we must adapt our behaviour, our understanding of the issues, our urban environments, our sporting events and our systems that look out for the vulnerable in our community.


The ConversationThis article was co-authored by Dr Mark Monaghan, an emergency physician, and Dr Liz Bashford, an anaesthetist, who are both members of Doctors for the Environment Australia.

David Shearman, Emeritus Professor of Medicine, University of Adelaide

This article was originally published on The Conversation. Read the original article.

Going to ground: how used coffee beans can help your garden and your health



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Coffee’s usefulness doesn’t have to end here.
Yanadhorn/Shutterstock.com

Tien Huynh, RMIT University

Did you know that your morning cup of coffee contributes to six million tonnes of spent coffee grounds going to landfill every year? This does not have to be the fate of your caffeine addiction and there are many opportunities to up-cycle spent coffee grounds into valuable commodities.

From fresh fruit, to roasted bean, to used up grounds, coffee’s chemical composition offers a range of uses beyond making your daily brew.




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Potential applications range from biofuels, to health products, and fertiliser for farms or your garden. So why are we throwing this precious product away?

The answer is that processing and production can be more complex than you might imagine – even when we’re talking about simply using coffee grounds in your garden. What’s more, many recycling initiatives to turn waste coffee into valuable commodities are still in their early stages.

When composted properly, coffee can be an excellent fertiliser.
Author provided

You may have noticed that some cafes now offer free spent coffee grounds for customers to take home and use in the garden. In theory, this is a great initiative but the reality is that fresh coffee grounds are high in caffeine, chlorogenic acid and tannins that are beneficial to humans but toxic to plants.

The spent coffee must be detoxified by composting for a minimum of 98 days for plants to benefit from the potassium and nitrogen contained in the roasted beans. Without adequate composting, the benefits are scant (see below). So if you do take some coffee grounds home from your local cafe, make sure you compost them before sprinkling them on the veggie patch.

Parsley plants after 70 days in soil containing a) 21 days composted spent coffee; b) fresh spent coffee grounds; c) newspaper; d) soil only; and e) fertiliser.
Brendan Janissen, unpublished experimental results., Author provided

The good news is that properly composted coffee grounds offer a cheap alternative to agro-industrial fertilisers, potentially helping urban communities become greener and more sustainable. Savvy businesses have begun processing coffee grounds on a commercial scale, turning them into nutrient-rich fertilisers or soil conditioners in convenient pellets for use in the garden.

The coffee berries before harvest.
Author provided

But why stop there? A potentially even more valuable ingredient is the chlorogenic acid. Although toxic to plants, as mentioned above, chlorogenic acid has potential as a natural health supplement for humans, because of its antioxidant, anticancer and neuroprotective properties.




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The whole coffee production process is abundant in chlorogenic acid, particularly in raw coffee beans. Chlorogenic acid conversion efficiency is even better from green coffee pulp, with a 50% recovery rate, compared with 19% for spent coffee grounds.

As undersized and imperfect beans are discarded at this raw stage, many businesses have seized the opportunity to market green coffee extracts as a weight loss product, although more research is needed to confirm this potential.

Roasted coffee beans ready for grinding.
Author provided

The list doesn’t end there. Coffee waste can be used to create a diverse list of chemicals, including enzymes and hormones for digestion of common biological compounds and to improve plant growth; and feedstocks for high-end crops such as mushrooms. Coffee oil has even been trialled as a fuel for London buses.

The ConversationWith abundant waste supplies due to the popularity of coffee consumption, by recycling the byproducts, perhaps we can enjoy one of our favourite beverages without too much guilt.

Tien Huynh, Senior Lecturer in the School of Sciences, RMIT University

This article was originally published on The Conversation. Read the original article.