Basketball fans around the world were recently sickened by the footage of NBA star Kevin Durant’s Achilles tendon rupturing during a game.
But while many think it’s only elite athletes who suffer from Achilles tendon issues, a fifth of the over-50 population actually suffers from Achilles tendinopathy (pain). And while very few of these will be ruptures, the pain can be frustratingly persistent and limit our ability to exercise and enjoy life.
What is Achilles tendinopathy?
The Achilles tendon is one of the strongest tendons in the human body. It attaches the calf muscles to the heel bone of the foot, helping you to run fast, jump high, and change direction quickly. During these types of exercises the tendon acts like a spring that propels you forward more efficiently.
Many labels are used to describe what’s going on when the tendon is injured. People are often told their tendon is torn and may think of it as a rope hanging on by a thread. These descriptions are unhelpful and inaccurate, often leading to expensive and unnecessary treatments.
We know words are extremely powerful and influence what treatment you think you need. For example, would you do the exercises your physiotherapist gave you if you believed your tendon was hanging on by a thread? Probably not.
Our work has found a painful tendon is not like a torn rope at all. It’s more like doughnuts stacked on top of each other. Even though changes in tendon structure are seen as a “hole” in the middle of the tendon, there is still a lot of delicious doughnut (in other words healthy tendon) surrounding the damaged area. The tendon adapts by getting thicker, making it stronger and allowing you to exercise.
Critically, pain poorly reflects damage. Tendon pain is not present because the tendon is damaged, weak or hanging on by a thread. More than 30% of AFL players have a “hole” in their tendon when we scan them but are able to play at the highest level with no pain.
Who gets it?
Achilles tendinopathy can affect athletes who participate in sports that involve running or explosive movements (Australian football, track and field). Most players do not miss competition as a result of Achilles tendon pain.
But our research found more than 20% of AFL players report that pain in their Achilles tendon significantly affects their training and performance. That’s four or five of your favourite 22 athletes playing this weekend.
But most people who experience this type of pain are aged 40-64 years.
That’s because the Achilles tendon bears the brunt of activities like running, playing golf, walking the dog, and stepping off the kerb throughout life. Being overweight, having diabetes, and high cholesterol all increase the risk of developing Achilles tendon pain. Tendon pain can lead to further weight gain and a greater impact on someone’s health beyond just their ability to run and exercise.
Overcoming tendon pain
The good news is that painful Achilles tendons rarely rupture. Some 80-90% of people who rupture their tendon have never had Achilles tendon pain. Your brain is clever as it uses pain to protect your Achilles tendon by changing your behaviour. But it’s easy to become overprotective.
Completely resting the tendon, either by using crutches or a walking boot, is one thing that should be avoided. This is because of the “use it or lose it” principle. With even two weeks’ rest, your tendon and calf muscles become weaker, meaning a longer recovery time.
Just like muscles, tendons get stronger with exercise. Starting exercise that produces no or minimal pain and progressively increasing the intensity of exercise is by far the best option, based on research.
In consultation with an experienced physiotherapist, this program should include strength training to help strengthen the tendon and the calf muscles. If you want to get back to running, slowly introduce exercise that requires the tendon to act like a spring, such as skipping and jumping.
These approaches should be a last resort, and actually all still require exercise to strengthen the tendon. Unfortunately, there are no shortcuts when recovering from a tendon injury.
Unlike Achilles in Greek mythology, your Achilles tendon does not have to be a point of weakness. Consulting with an experienced physiotherapist to develop a progressive exercise program is the best protection you can have against further injury.
Researchers from the University of Nottingham in the UK recently published a study in the journal Scientific Reports suggesting caffeine increases brown fat.
This caught people’s attention because brown fat activity burns energy, which may help with weight loss. Headlines claimed drinking coffee can help you lose weight, and that coffee is possibly even the “secret to fighting obesity”.
Unfortunately, it’s a little more complicated than that. The researchers did find caffeine stimulated brown fat, but this was mainly in cells in a lab.
For a human to reap the benefits seen in the cells, we estimate they’d need to drink at least 100 cups of coffee.
Although part of this research did look at people, the methods used don’t support coffee or caffeine as weight-loss options.
What is brown fat?
Brown adipose (fat) tissue is found deep within the torso and neck. It contains fat cell types which differ from the “white” fat we find around our waistlines.
Brown fat cells adapt to our environment by increasing or decreasing the amount of energy they can burn when “activated”, to produce heat to warm us up.
When people are cold for days or weeks, their brown fat gets better at burning energy.
We understand caffeine may be able to indirectly accentuate and prolong some of these processes, mimicking the effects of cold exposure in stimulating brown fat.
Brown fat – and anything thought to increase its activity – has generated significant research interest, in the hope it might assist in the treatment of obesity.
What did the researchers do in this latest study?
The research team first conducted experiments where cells taken from mice were grown into fat cells in petri dishes. They added caffeine to some samples, but not others, to see whether the caffeinated cells acquired more brown fat attributes (we call this “browning”).
The dose of caffeine (one millimolar) was determined based on what would be the highest concentration that browned the cells but didn’t kill them.
The fat cell culture experiment showed adding caffeine did “brown” the cells.
The researchers then recruited a group of nine people who drank a cup of instant coffee, or water as a control.
Before and after the participants drank coffee, the researchers measured their brown fat activity by assessing the temperature of the skin near the neck, under which a major region of brown fat is known to lie.
Skin temperature increased over the shoulder area after drinking coffee, whereas it didn’t after drinking only water.
How should we interpret the results?
Some people will criticise the low number of human participants (nine). We shouldn’t make broad recommendations on human behaviour or medicine based on small studies like this, but we can use them to identify new and interesting aspects of how our bodies work – and that’s what these researchers sought to do.
But whether the increased skin temperature after drinking coffee is significant cannot be determined for a few important reasons.
Firstly, although the study showed an increase in skin temperature after drinking coffee, the statistical analysis for the human experiment doesn’t include enough data to accurately compare the coffee and water groups, which prevents meaningful conclusions. That is, it doesn’t use appropriate methods we apply in science to decide if something really changed or only happened by chance.
Second, measuring skin temperature is not necessarily the most accurate indicator for brown fat in this context. Skin temperature has been validated as a way to measure brown fat after cold exposure, but not after taking drugs which mimic the effects of cold exposure – which caffeine is in the context of this study.
Myself and other researchers have shown the effects of these “mimic” drugs result in diverse effects including increased blood flow to the skin. Where we don’t know if changes in the skin temperature are due to brown fat or unrelated factors, relying on this measure may be problematic.
Although also suffering its own limitations, PET (poistron emission tomography) imaging is currently our best option for directly measuring active brown fat.
It’s the dose that matters most
The instant coffee used in the study contained 65mg of caffeine, which is standard for a regular cup of instant coffee. Brewed coffees vary and might be double this.
Regardless, it’s difficult to imagine this dose could increase brown fat energy burning when studies using large doses of more potent “cold-mimicking” drugs (such as ephedrine) cause no, or at best modest, increases in brown fat activity.
But let’s look at the caffeine dose used in the cell experiments. The one millimolar concentration of caffeine is a 20-fold larger dose than 300-600mg of caffeine dose used by elite athletes as a performance-boosting strategy. And this dose is five to ten times higher than the amount of caffeine you’d get from drinking an instant coffee.
Rough calculations therefore suggest we’d need to drink 100 or 200 cups of coffee to engage the “browning” effects of caffeine.
So people should continue to drink and enjoy their coffee. But current evidence suggests we shouldn’t start thinking about it as a weight loss tool, nor that it has anything meaningful to do with brown fat in humans. – Andrew Carey
Blind peer review
This Research Check is a fair and balanced discussion of the study. The limitations identified by this Research Check apply equally to diabetes, which the study encompassed, but didn’t get picked up as much in the headlines.
Coffee contains more than caffeine, and while there is some evidence that modest coffee consumption may reduce diabetes risk, decaffeinated coffee seems to be as effective as caffeinated coffee. This is consistent with the point made by the Research Check that you would need to drink an implausible number of cups of coffee to produce the effect seen with caffeine in the cultured fat cells. – Ian Musgrave
Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.
Nike’s London store recently introduced a plus-sized mannequin to display its active clothing range which goes up to a size 32.
The mannequin triggered a cascade of responses ranging from outrage to celebration. One side argues that the mannequin normalises obesity and leads obese people to feel that they are healthy when in fact they are not.
The other side argues the representations are inclusive, combat fat stigma and encourage fat women to exercise.
Both arguments have some merit.
The representations of bodies we see around us — including shop mannequins – affect the way we calibrate our sense of what is normal and acceptable. And obesity is indeed associated with a greater risk of heart disease, stroke, type 2 diabetes and early death.
It is possible to be metabolically healthy and fat. But even metabolically healthy obese people may still have a shorter life expectancy than their lean peers.
On the other hand, exercise is almost universally beneficial, and people of all shapes and sizes should be encouraged to participate.
Overweight and obesity have become the new normal
Based on body mass index (BMI), about two-thirds of Australian adults and one-quarter of kids are overweight or obese. While this proportion has flattened out for children in the last 20 years, it continues to rise for adults.
There is strong evidence parents consistently misjudge the weight status of their children because they see more and more fat kids.
The same is true for adults: a recent study from the United Kingdom found 55% of overweight men and 31% of overweight women considered their weight to be in the healthy range.
I would guess the Nike mannequin is close to 100 kg, with a BMI maybe in the low 30s, well into the obese category.
But given the average female shop mannequin has a BMI of about 17, there are probably at least ten times as many Australian women like the plus-size mannequins than like the usual minus-size variety.
Obesity is not a lifestyle choice like smoking
Obesity is necessarily the result of behaviours — eating too much, exercising too little — albeit heavily constrained by genetic predispositions, and social and economic pressures.
But unlike, say, smoking, being fat is also part of what a person is: most people who are fat have usually been fat for a long time. It’s not something a person has complete control over.
Divergent paths into fat and lean start very young, and once you’re on the obesity train it’s hard to get off.
While it is possible to “give up obesity”, for many it can be a very hard road, involving a lifelong struggle with hunger and recidivism.
Empowering vs shaming
Anti-obesity campaigns that are built on disgust, fear or shame – such as Measure Up – have been criticised as being stigmatising, ethically problematic and ineffective.
There has, to my knowledge, been no high-quality research comparing the actual effectiveness of shaming versus empowering anti-obesity, or pro-physical activity, campaigns.
However a number of studies show, unsurprisingly, that obese and inactive people prefer empowering campaigns, find them more motivating and less stigmatising.
Health risks of obesity
It has been argued one can be “fit and healthy at any size”: that an obese person can be as fit and healthy as a lean person.
Depending on definitions, about 25-50% of obese people have “metabolically healthy obesity” – normal levels of inflammation, blood sugar, insulin, blood fats, and blood pressure. Other than being obese, these people appear healthy.
But obese people — fit or unfit, active or not — remain on average at greater risk of heart disease, diabetes and early death than lean people with similar behaviours.
Similarly, the claim that people can be both fit and fat, and that fit, fat people are at less risk than unfit, lean people depends on how we define fitness and fatness.
One study, for example, might compare overweight people in the top 20% of fitness with lean people in the bottom 20%. Because there are modest differences in fatness and big differences in fitness, fat people are much more likely to have a similar risk to lean people.
But if another study compares obese people in the top 50% of fitness to lean people in the bottom 50%, the fatter people will be much less healthy.
What is certain is that whoever you are, exercise will almost certainly improve your health.
The Nike mannequin controversy is a morality tale of how we navigate between the devil of normalising obesity and the deep blue sea of excluding obese people from the world of exercise.
Obesity has been called both a disability and a disease, and just another way of being in the world. The reality is that for most people, it’s something in between.
In the 12 years to 2015, life expectancy in Australia increased by 2.3 years for men (to 80.4) and 1.6 years for women (to 84.6). Our health-adjusted life expectancy increased along with it – by two years for men (to 71.5) and 1.3 years for women (to 74.4).
Health-adjusted life expectancy estimates the number of full health years people can expect to experience over the course of their lives. By comparing this measure to life expectancy, we can see whether longer life expectancy is accompanied by more years lived in full health.
Pleasingly, these trends show we’re not just living for longer – but we’re staying healthy for longer, too.
In the Australian Burden of Disease study, released today, the Australian Institute of Health and Welfare has mapped the impact and causes of illness and death in Australia between 2003 and 2015.
The improvement in health-adjusted life expectancy alongside life expectancy in the last 12 years builds on continual improvements in life expectancy seen in Australia over several decades.
These improvements in our health can be accorded to advancements in science and medicine, and certain changes we’ve made in our lifestyles. But there’s still plenty of room to do better.
How have we achieved this?
Some 89% of the health improvement between 2003 and 2015 was due to improvements in heart health, reductions in cancer, and improved infant health.
Health improvement refers to reductions in the burden of disease, measured in disability adjusted life years (DALYs). DALYs take into account premature death as well as the burden of illness and disability caused by disease and injury.
Heart disease and stroke
In the period from 2003 to 2015, there was a 36% reduction in the age-standardised burden of disease due to heart disease and stroke. Improvements in heart health accounted for 56% of the overall improvement in health.
The vast majority of the reduction in the cardiovascular disease burden has been due to reductions in smoking, high blood pressure and high cholesterol. Some of the improvement is due to better treatment (for example, surgical interventions like stent insertions).
We’ve been seeing strong progress in this area over many years. The chance of dying from heart disease or stroke is now one sixth of what it was in 1970.
Cancer and infant health
The reduction in the burden of disease from cancer, which accounted for 25% of the improvement in health, has been partly due to the reduction in risk factors such as smoking. Prevention through screening has also played an important role.
But improved treatment, in the form of drugs, radiation and surgery, has been the most important factor. Five year survival rates for cancer increased from 50% in 1986-1990 to 69% in 2011-2015.
Reductions in the burden of disease due to infant and congenital conditions accounted for 8% of the improvement in health between 2003 and 2015. This was due to improved treatment of infants with congenital conditions and better prevention of problems such as sudden infant death syndrome (SIDS).
Managing our risk factors is key
Overall, reductions in risk factors has been responsible for 51% of the health improvement we’ve seen between 2003 and 2015.
Although some risk factors like overweight and obesity have worsened, the decline in smoking, high blood pressure, high cholesterol and alcohol use has more than compensated for those risk factors which have worsened or those risk factors, like physical inactivity, which have not improved.
We’re by no means reaching the end of the line in terms of opportunities to improve our health.
Some 38% of the burden of disease in 2015 was due to risk factors like smoking (still accounting for 9.3% of the burden), overweight and obesity (8.4% of the burden), poor diet (7.3%), high blood pressure (5.8%), excessive alcohol intake (4.5%), high cholesterol (3%), insufficient physical activity (2.5%) and child abuse and neglect (2.2%).
Health isn’t equal
The report reveals significant inequalities in health, with those living in the poorest areas having a health-adjusted life expectancy at least five years lower than those living in the richest areas.
The burden of disease in the poorest areas is 50% higher than in the richest areas. For some diseases like heart disease, the burden of disease is 70% higher in the lowest socioeconomic areas, whereas for cancer the burden of disease is 40% higher.
So the news isn’t all good. While there’s opportunity for us to manage our risk factors on an individual level, these health disparities warrant urgent attention on a broader health policy level.
It’s normal to feel stressed at work from time to time. But for some people, the stress becomes all-consuming, leading to exhaustion, cynicism and hatred towards your job. This is known as burnout.
Burnout used to be classified as a problem related to life management, but last week the World Health Organisation re-labelled the syndrome as an “occupational phenomenon” to better reflect that burnout is a work-based syndrome caused by chronic stress.
The newly listed dimensions of burnout are:
- feelings of energy depletion or exhaustion
- increased mental distance from one’s job, or feelings of negativism or cynicism related to one’s job
- reduced professional efficacy (work performance).
In the era of smartphones and 24-7 emails, it’s becoming increasingly difficult to switch off from the workplace and from those who have power over us.
The new definition of burnout should be a wake-up call for employers to treat chronic stress that has not been successfully managed as a work health and safety issue.
How do you know if you’re burnt out?
If you think you might be suffering burnout, ask yourself the following questions:
has anyone close to you asked you to cut down on your work?
in recent months have you become angry or resentful about your work or about colleagues, clients or patients?
do you feel guilty that you are not spending enough time with your friends, family or even yourself?
do you find yourself becoming increasingly emotional, for example crying, getting angry, shouting, or feeling tense for no obvious reason?
If you answered yes to any of these questions, it might be time for change.
These questions were devised for the United Kingdom Practitioner Health Programme and are a good starting point for all workers to identify if you are at risk of burning out.
(You can also complete the British Medical Association’s online burnout questionnaire, although it’s tailored for doctors so the drop-down menu will ask you to select a medical specialty).
If you think you’re suffering burnout, the first step is to talk to your line manager or workplace counsellor. Many workplaces now also have confidential external psychologists as part of their employee assistance programme.
What causes burnout?
We all have different levels of capacity to cope with emotional and physical strains.
When we exceed our ability to cope, something has to give; the body becomes stressed if you push yourself either mentally or physically beyond your capacity.
People who burn out often feel a sense of emotional exhaustion or indifference, and may treat colleagues, clients or patients in a detached or dehumanised way. They become distant from their job and lose the zeal for their chosen career.
They might become cynical, less effective at work, and lack the desire for personal achievement. In the long term, this is not helpful for the person or the organisation.
Who is most at risk?
Any worker who deals with people has the potential to suffer from burnout. This might include teachers, care workers, prison officers or retail staff.
Emergency service workers – such as police, paramedics, nurses and doctors – are at even higher risk because they continually work in high-stress conditions.
A recent survey of 15,000 US doctors found 44% were experiencing symptoms of burnout. As one neurologist explained:
I dread coming to work. I find myself being short when dealing with staff and patients.
French research on hospital emergency department staff found one in three (34%) were burnt out because of excessive workloads and high demands for care.
Lawyers are another profession vulnerable to burnout. In a survey of 1,000 employees of a renowned London law firm, 73% of lawyers expressed feelings of burnout and 58% put this down to the need for a better work-life balance.
No matter what job you do, if you are pushed beyond your ability to cope for long periods of time, you’re likely to suffer burnout.
It’s OK to say no to more work
Employers have an organisational obligation to promote staff well-being and ensure staff aren’t overworked, overstressed, and headed towards burnout.
There are things we can all do to reduce our own risk of burnout. One is to boost our levels of resilience. This means we’re able to respond to stress in a healthy way and can bounce back after challenges and grow stronger in the process.
You can build your resilience by learning to switch off, setting boundaries for your work, and thinking more about play. As much as you can, inoculate yourself against job interference and prevent it from ebbing into your personal life.
No matter what your profession, don’t let your job become the only way you define yourself as a person.
And if your job is making you miserable, consider moving jobs or at least have a look at what else is out there. You may surprise yourself.
If you or anyone you know needs help or support, you can call Lifeline on 13 11 14.
Michael Musker, Senior Research Fellow, South Australian Health & Medical Research Institute
The story of Yumiko Kadota, whose gruelling schedule as a Sydney hospital registrar included clocking up more than 100 hours of overtime in her first month, has highlighted the punishing work schedules required in the medical profession.
Research indicates working more than 48 hours a week is associated with significant declines in productivity, more mistakes and more mental health problems. Yet the Royal Australasian College of Surgeons reckons working up to 65 hours a week “is appropriate for trainees to gain the knowledge and experience required”.
It’s an attitude that explains why a 2017 audit found more than 70% of surgeons in public hospitals were working unsafe hours. And it’s symptomatic of many areas where pushing the hours envelope is seen as part of the job.
Last month, for example, a study by the Australian Transport Safety Bureau found almost one in four long-haul pilots reported working on less than five hours of sleep in the previous 24 hours – putting them in the risk zone where fatigue leads to impaired performance.
Meanwhile, two of Australia’s largest law firms are being investigated for overworking staff. At King & Wood Mallesons in Melbourne, lawyers working on the banking royal commission were reportedly sleeping in their offices overnight, too tired to go home. At Gilbert + Tobin Lawyers in Sydney, it is alleged lawyers were resorting to drugs and other supplements to cope with fatigue.
Other areas in which long hours are common are in mining, farming and construction. All up about 13% of the workforce – 19% of men and 6% of women – are working 50 hours or more, putting themselves, and others, at risk.
What’s the damage
After a century of “scientific management” you might think that more attention would be paid to the scientific studies on working long hours.
The relationship between work hours and productivity follows the economic law of diminishing returns. Productivity peaks at a certain point and then declines. Work too long and you get to the point where you’re achieving nothing; or are even doing damage.
This is what the research literature tells us:
- After working 39 hours a week, mental health tends to decline.
- After 48 hours, job performance begins to rapidly decrease. There are more signs of depression and anxiety, and worse sleep quality associated with long-term health risks such as cardiovascular disease, type 2 diabetes and cancer.
- Working more than 10 hours a day increases the risk of workplace injury by 40%, and more than 12 hours a day doubles it.
- Longer working hours harm relationships, erode job satisfaction and contribute to depression, including increased suicidal thoughts.
A rule made to be broken
All of this research shows there’s good sense in Australia’s federal Fair Work Act (s. 62) capping the standard work week at a maximum of 38 hours.
But that maximum is easy to flout. The act also says an employer can require an employee to work “reasonable” extra hours. Determining whether they are unreasonable depends on 10 factors, including a risk to health and safety, family circumstances, the needs of the business, compensation, the usual patterns of work in the industry and “any other relevant matter”.
The law says an employee can refuse to work more than 38 hours a week, but in practice that rarely happens.
You may be happy to put in more hours because you are compensated. You may even do it “voluntarily”, because you see it as a path to promotion, or the way to keep your job. You may be enmeshed in a “first in, last out” culture, where it’s a competition to show your devotion to your job through the number of hours you work.
As a result, Australians work an average six hours of unpaid overtime a week.
Gaming the system
Management practices can promote an overtime culture without explicitly flouting the law.
One way is to scrutinise an employee’s working hours, such as using a billable hours system. This is common in law firms and other professional services. Clients are charged by the hour (or six-minute increments, as is the case in law firms) for the time an employee spends working on a matter. It puts pressure on a conscientious employee to do any work not related to a client in their own time. An employee may also under-report hours so as not look slow or unproductive to a manager.
Another way is through using casual or contract workers. Such employment can result in workers doing more hours than what they are paid for, either because they have underquoted to get the job, or are working on a fixed contract where the employer has defined how long it should take, or they feel the need to prove their worth to ensure they get more work.
But for those powers to make a difference, these agencies need more resources to actually do investigations and greater powers to issue fines and corrective measures to companies where overtime is endemic. There’s no reason hours auditing couldn’t be a more routine procedure, much like food health and safety regulators inspect restaurants.
But more than that we need a change in the cultural attitudes that promote long hours as necessary, acceptable or heroic – even when someone doing their job while overtired and fatigued, such as a surgeon or pilot, is downright scary.
Best of all, it’s free, we can do it anywhere and, for most of us, it’s relatively easy to fit into our daily routines.
We often hear 10,000 as the golden number of steps to strive for in a day. But do we really need to take 10,000 steps a day?
Not necessarily. This figure was originally popularised as part of a marketing campaign, and has been subject to some criticism. But if it gets you walking more, it might be a good goal to work towards.
Where did 10,000 come from?
The 10,000 steps concept was initially formulated in Japan in the lead-up to the 1964 Tokyo Olympics. There was no real evidence to support this target. Rather, it was a marketing strategy to sell step counters.
There was very little interest in the idea until the turn of the century, when the concept was revisited by Australian health promotion researchers in 2001 to encourage people to be more active.
Based on accumulated evidence, many physical activity guidelines around the world – including the Australian guidelines – recommend a minimum of 150 minutes of moderate intensity physical activity a week. This equates to 30 minutes on most days. A half hour of activity corresponds to about 3,000 to 4,000 dedicated steps at a moderate pace.
Are you walking your dog enough?
One size doesn’t fit all
Of course, some people accumulate a lot fewer steps per day – for example, older people, those with a chronic disease, and office workers. And others do a lot more: children, runners, and some blue-collar workers. So the 10,000 goal is not suitable for everyone.
Setting a lower individual step goal is fine as long as you try to add about 3,000 to 4,000 steps to your day. This means you will have done your 30 minutes of activity.
Studies that examine how the number of daily steps relates to health benefits have mainly been cross-sectional. This means they present a snapshot, and don’t look at how changes in steps affect people’s health over time. Therefore, what we call “reverse causality” may occur. So rather than more steps leading to increased health benefits, being healthier may in fact lead to taking more steps.
Nonetheless, most studies do find taking more steps is associated with better health outcomes.
Several studies have shown improved health outcomes even in participants who take less than 10,000 steps. An Australian study, for example, found people who took more than 5,000 steps a day had a much lower risk of heart disease and stroke than those who took less than 5,000 steps.
Another study found that women who did 5,000 steps a day had a significantly lower risk of being overweight or having high blood pressure than those who did not.
The more the better
Many studies do, however, show a greater number of steps leads to increased health benefits.
An American study from 2010 found a 10% reduction in the occurrence of metabolic syndrome (a collection of conditions that increase your risk of diabetes, heart disease and stroke) for each 1,000-step increase per day.
An Australian study from 2015 demonstrated that each 1,000-step increase per day reduced the risk of dying prematurely of any cause by 6%, with those taking 10,000 or more steps having a 46% lower risk of early death.
Another Australian study from 2017 showed people with increasingly higher step counts spent less time in hospital.
So the bottom line is the more steps, the better.
Step it up
It’s important to recognise that no public health guideline is entirely appropriate for every person; public health messages are aimed at the population at large.
That being said, we shouldn’t underestimate the power of a simple public health message: 10,000 steps is an easily remembered goal and you can readily measure and assess your progress. You can use an activity tracker, or follow your progress through a program such as 10,000 Steps Australia.
Increasing your activity levels, through increasing your daily step count, is worthwhile; even if 10,000 steps is not the right goal for you. The most important thing is being as active as you can. Striving for 10,000 steps is just one way of doing this.
Corneel Vandelanotte, Professorial Research Fellow: Physical Activity and Health, CQUniversity Australia; Kerry Mummery, Dean, Faculty of Kinesiology, Sport and Recreation, University of Alberta; Mitch Duncan, , University of Newcastle, and Wendy Brown, Professor of Human Movement Studies, The University of Queensland
This article is part of our occasional long read series Zoom Out, where authors explore key ideas in science and technology in the broader context of society and humanity.
Scientists love analogies. We use them continually to communicate our scientific approaches and discoveries.
As an immunologist, it strikes me that many of our recurring analogies for a healthy, functioning immune system promote excellent behaviour traits. In this regard, we should all aim to be a little more like the cells of our immune system and emulate these characteristics in our lives and workplaces.
Here are five life lessons from your immune system.
1. Build diverse and collaborative teams
Our adaptive immune system works in a very specific way to detect and eradicate infections and cancer. To function, it relies on effective team work.
At the centre of this immune system team sits dendritic cells. These are the sentinels and leaders of the immune system – akin to coaches, CEOs and directors.
They have usually travelled widely and have a lot of “life experience”. For a dendritic cell, this means they have detected a pathogen in the organs of the body. Perhaps they’ve come into contact with influenza virus in the lung, or encountered dengue fever virus in the skin following a mosquito bite.
After such an experience, dendritic cells make their way to their local lymph nodes – organs structured to facilitate immune cell collaboration and teamwork.
Here, like the best leaders, dendritic cells share their life experiences and provide vision and direction for their team (multiple other cell types). This gets the immune cell team activated and working together towards a shared goal – the eradication of the pathogen in question.
The most important aspect of the dendritic cell strategy is knowing the strength of combined diverse expertise. It is essential that immune team members come from diverse backgrounds to get the best results.
To do this, dendritic cells secrete small molecules known as chemokines. Chemokines facilitate good conversations between different types of immune cells, helping dendritic cells discuss their plans with the team. In immunology, we call this “recruitment”.
Much like our workplaces, diversity is key here. It’s fair to say, if dendritic cells only recruited more dendritic cells, our immune system would completely fail its job. Dendritic cells instead hire T cells (among others) and share the critical knowledge and strategy to steer effective action of immune cells.
T cells can then pass these plans down the line – either preparing themselves to act directly on the pathogen, or working alongside other cell types, such as B cells that make protective antibodies.
In this way, dendritic cells establish a rich and diverse team that works together to clear infections or cancer.
2. Learn through positive and negative feedback
Immune cells are excellent students.
During development, T cells mature in a way that depends on both positive and negative feedback. This occurs in the thymus, an organ found in the front of your chest and whose function was first discovered by Australian scientist Jacques Miller (awarded the 2018 Japan Prize for his discoveries).
As they mature, T cells are exposed to a process of trial and error, and take on board criticism and advice in equal measure, to ensure they are “trained” to respond appropriately to what they “see” (for example, molecules from your own body, or from a foreign pathogen) when they leave the thymus.
Importantly, this process is balanced, and T cells must receive both positive and negative feedback to mature appropriately – too much of either on its own is not enough.
In the diverse team of the immune system, cells can be both the student and the teacher. This occurs during immune responses with intense cross-talk between dendritic cells, T cells and B cells.
In this supportive environment, multiple rounds of feedback allow B cells to gain a tighter grip on infections, tailoring antibodies specifically towards each pathogen.
The result of this feedback is so powerful, it can divert cells away from acting against your own body, instead converting them into active participants of the immune system team.
Developing avenues that promote constructive feedback offers potential to correct autoimmune disorders.
3. A unique response for each situation
Our immune system knows that context is important – it doesn’t rely on a “one-size–fits-all” approach to resolve all infections.
This allows the cells of our immune system to perfectly respond to different types of pathogens: such as viruses, fungi, bacteria and helminths (worms).
In these different scenarios, even though the team members contributing to the response are the same (or similar), our immune system displays emotional intelligence and utilises different tools and strategies depending on the different situations, or pathogens, it encounters.
Importantly, our immune system needs to carefully control attack responses to get rid of danger. Being too heavy handed leaves us with collateral tissue damage, such as is seen allergy and asthma. Conversely, weak responses lead to immunodeficiencies, chronic infection or cancer.
A major research aim for people working in immunology is to learn how to harness balanced and tailored immune responses for therapeutic benefit.
Can I prevent food allergies in my kids?
4. Focus on work/life balance
When we are overworked and poorly rested, we don’t function at our peak. The same is true for our immune cells.
An overworked immune cell is commonly referred to as being “chronically exhausted”. In this state, T cells are no longer effective at attacking tumour or virus-infected cells. They are lethargic and inefficient, much like us when we overdo it.
For T cells, this switch to exhaustion helps ensure a balanced response and avoids collateral damage. However, viruses and cancers exploit this weakness in immune responses by deliberately promoting exhaustion.
The rapidly advancing field of immunotherapy has tackled this limitation in our immune system head-on to create new cancer therapeutics. These therapies release cells of their exhaustion, refresh them, so they become effective once more.
This therapeutic avenue (called “immune checkpoint inhibition”) is like a self-care day spa for your T cells. It revives them, renewing their determination and efficiency.
This has revolutionised the way cancer is treated, leading to the award of the 2018 Nobel prize in Medicine to two of its pioneers, James P. Allison and Tasuku Honjo.
5. Learn from life experiences
The cornerstone of our adaptive immune system is the ability to remember our past infections. In doing so, it can respond faster and in a more targeted manner when we encounter the same pathogen multiple times.
Quite literally, if it doesn’t kill you, it makes your immune system stronger.
Vaccines exploit this modus operandi, providing immune cells with the memories without the risk of infection.
Work still remains to identify the pathways that optimise formation of memory cells that drive this response. Researchers aim to discover which memories are the most efficient, and how to make them target particularly recalcitrant infections, such as malaria, HIV-AIDS and seasonal influenza.
While life might not have the shortcuts provided by vaccines, certainly taking time to reflect and learn after challenges can allow us to find better, faster solutions to future problems.
It’s a message that’s been drummed into us since childhood. Drink water, especially when it’s hot, otherwise you’ll get dehydrated.
But how do you know if you’re dehydrated? Who’s more at risk? And what can you do about it?
What’s dehydration and why does it matter?
When people use the term dehydration, they usually refer to what doctors call “volume depletion” or hypovolaemia.
Volume depletion is a reduction in the volume of water in the blood vessels. But dehydration is quite different and is less common. It’s the loss of water from both blood vessels and the body’s cells.
Doctors are concerned about volume depletion and dehydration because adequate hydration is required for the body to function normally. Water maintains our body temperature and lubricates our joints. Our body’s cells rely on water as does our circulatory, respiratory, gastrointestinal and neurological systems.
Severe cases of volume depletion can lead to shock and collapse. Without resuscitation with fluid, the consequences may be devastating.
Water, water everywhere
A 70kg person is made up of 40L (40kg) is water. Two-thirds of that water is in the cells (intracellular), one-third outside the cells (extracellular).
Outside the cells, 20% of body water is in plasma (around 3L), which together with red bloods cells (2L) gives a total 5L of blood. It’s the movement of water between compartments that maintains each one’s biochemical composition, allowing your cells and body to work normally.
The total body water volume (water in both the blood vessels and the body’s cells) is remarkably constant given the large variation in how much an individual might take in and lose each day.
Water intake is accounted for mostly by how much and what you drink and eat, and the daily variation is regulated by the kidney, which alters your urine output.
The main function of the kidney is to regulate the volume and composition of body fluids within narrow limits by altering output.
When you drink large volumes of fluid, your body can afford to get rid of increased amounts of dilute urine. But when you drink a minimal amount of fluid, your urine is concentrated and you pass only a small volume.
If you’re urinating less often than normal, or urinating small volumes of darker coloured urine, it may be time to drink more water.
Other small losses of water include through stool, sweat and lungs.
So if you have diarrhoea or are exercising in the heat, for instance, you will need to drink more fluids.
As fluid is lost from the extracellular compartment such as in cases of diarrhoea and vomiting or bleeding, you can develop symptoms of volume depletion including:
- thirst, including a dry mouth
- dizziness, particularly when standing due to the low blood pressure (a consequence of volume loss)
- and when very severe, confusion (a consequence of inadequate oxygenation of the brain).
Doctors might also note:
- that it takes longer for your skin to bounce back when pinched (known as reduced skin turgor)
- low blood pressure as a reduction in volume directly affects blood pressure
- an increased heart rate, in an attempt by the body to maintain blood pressure
- reduced weight as fluid makes up two-thirds of body weight. A loss of 1L of fluid will read as a drop in 1kg on the scales.
Blood testing will often reveal a degree of kidney impairment. That’s because the kidneys require a large blood flow to work normally.
In cases of volume depletion and reduction in blood pressure, blood flow to the kidneys is compromised and they go into a state of “shock”. Mostly this is reversible when volume and blood pressure is restored.
As there’s no single test for volume depletion, doctors will make a diagnosis after taking a note of your history, examining you and a combination of blood and urine tests.
Here’s what happened to Tom
I was on call at the hospital recently when, at 9.45pm on a Sunday, I received a call from the emergency department.
Tom, a 78 year old man, had come in by ambulance after neighbours had found him on his bedroom floor. Tom’s cognition was not great at the best of times, and that night he couldn’t tell us how long he had been on the floor.
There were no obvious injuries, his blood pressure was low (100/60mmHg), pulse rate high (98 beats per minute) and his temperature was normal. Blood tests showed he had low sodium salt levels and kidney impairment.
Tom had been in the emergency department for six hours by the time the call came to me; in that time he had not passed urine. It all pointed to volume depletion.
We treated Tom with intravenous fluid. He needed 5L over 48 hours, after which he was passing urine again. His blood pressure was back to normal 140/70mmHg, his kidney function had normalised and his weight was up from 46kg on admission to 50kg.
Tom told us he had fallen while getting up at night. He had been on the floor for most of the next day and had not eaten or drunk anything for hours.
Who’s most at risk and why?
Some groups are more susceptible to volume depletion, including:
- elderly people like Tom, as our total body water reduces with age and the elderly often have a reduced sensation of thirst. Many older people also have other health problems including chronic kidney disease, which may impact the ability to concentrate urine when the volume is depleted
- babies, because they aren’t able to articulate when they’re thirsty. They have a higher metabolic rate than adults meaning they require more fluid
- people with impaired thirst mechanisms such as the elderly or people with certain brain injuries
- people losing large volumes of fluid via the bowel (from diarrhoea or through a colostomy)
- people taking medications that promote water loss, in particular diuretics, often referred to as water tablets.
These vulnerable groups need to be aware of the increased risk of volume depletion, minimise their risk by maintaining fluid levels, recognise the symptoms of volume depletion early, and seek prompt treatment, including going to hospital if necessary.
If you experience the symptoms of volume depletion it’s important to take heed. At home, start with water if you’re thirsty. Once dizziness is present, significant volume loss has ensued and a trip to the doctor is in order. Confusion mandates emergency treatment.
How about physiological dehydration?
Physiological dehydration, which occurs when water is lost from both the blood vessels and from the body’s cells compartment, is distinct from volume depletion. But there are many overlapping symptoms, such as thirst, a drop in blood pressure and when severe, confusion.
Dehydration can happen with prolonged and sustained high blood sugar levels as can occur in someone with diabetes. This is because the high sugar levels in the blood pull water out of the cells in an attempt to lower the levels. High sugar levels also make you pass more urine. So in this instance there is loss of fluid from both the intracellular and extracellular compartments.
Explainer: what is diabetes?
So for those with diabetes, monitoring blood sugar levels is important. If the blood sugar is persistently high it’s important to seek medical advice to reduce the level safely and prevent dehydration.
In a nutshell
Water is vitally important to the normal function of the body. Volume depletion can occur during anytime of the year, but people are particularly prone over the summer months. The key is prevention and knowing what the signs and symptoms are. So in summer keep your fluids up; talk to your doctor about any medications that may need adjusting (such as diuretics) and keep an eye out for friends, family and neighbours.