The Experts

Ross Walker
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The common cold - could there soon be a cure?

Thursday, May 17, 2018


It has often been said that man can put a space rocket on the moon but cannot cure the common cold. It appears that we may be closer to ridding the planet of this annoying scourge.

Although the common cold is not life-threatening, it certainly disrupts your life, makes you feel dreadful for a few days and also is an extremely common cause of workplace absence. The common cold is significantly contagious and typically causes a sore throat, a blocked or runny nose, moderate fevers and a few days of feeling unwell. 

Researchers from the Imperial College in London have discovered a key protein in normal body cells. This protein known as N-Methyl tryptamine (NMT) basically allows the cold virus to attach to a normal cell, replicate and spread throughout the body. The UK scientists have developed a drug that targets NMT, blocking the cold virus’s ability to cause infection. In further studies, the scientists are developing an inhaled form of the drug which will work rapidly and because of lack of significant systemic absorption, should have less side effects. 

The test drug was used on several strains of the common cold virus, otherwise known as rhinovirus and blocks the effects on human cells in the laboratory without appearing to cause any harm.

There are no current treatments for the common cold and there are a number of common misconceptions that need to be stressed at this time of year as we in Australia are entering into winter. Although you can develop cold symptoms at any time of the year, they are clearly much more common in the cold months thus the term, the common cold. 

  1. When a person says they have the flu, this is typically not the case and in fact they have the common cold. The flu actually refers to influenza which is a different type of virus that causes a much more severe, serious and prolonged infection
  2. The flu vaccine is specifically for influenza and does not prevent you developing the common cold
  3. You cannot develop influenza from the vaccine but you may have a flulike reaction (which is much milder than influenza itself) for a few days after the vaccination
  4. Antibiotics are completely unnecessary and actually harmful for people suffering the common cold or influenza. They are only useful if there is a proven bacterial infection following a throat swab or sputum culture.

Unfortunately, this potential cure for the common cold may not be available clinically for a few years to come, until it’s safety in actual humans (not cultured human cells in laboratory) has been proven.

In the meantime, there is a reasonable evidence base around the following treatments if you feel a cold starting to occur:

  1. A study from Finland using high dose vitamin C 6-8 grams daily for a few days has been shown to significantly reduce the severity and length of a cold
  2. High dose echinacea
  3. High dose garlic
  4. Zinc lozenges.

In my opinion and experience, one or a combination of all of the above are safe and should be used for a few days at the onset of symptoms, until relief. Regardless, the common cold is an imposition rather than a serious illness and it’s probably not that bad to challenge your immune system with minor viruses every now and then, purely to keep it on its toes.


Male Menopause - does it exist?

Thursday, May 10, 2018


All women will experience menopause at some stage in midlife. For around 95%, this will occur at sometime between age 45 to 55. But, over the past few decades, scientific evidence has emerged that a similar process occurs in most males. This has led to the term, andropause. 

Basically, the peak of anyone’s life is age 30, and from that point on there is a slow but steady decline in all the body’s metabolic processes including our hormonal systems. This is also true for our reproductive hormones. For women, this is obvious through the loss of the normal menstrual cycle, along with many of the other symptoms that are common during this period of their life. Hot flushing, mood swings, irritability, depression and generalised aches and pains are very common during this time, with most women experiencing at least one of these symptoms during the course of menopause. But, many of the symptoms also occur in men. 

The additional symptom that also occurs in men is a degree of erectile dysfunction. Thus, andropause may certainly be a difficult time for men, just as menopause is for women. But, apart from the obvious discomfort and annoyance of symptoms, are there any health consequences in the reduction in the male hormone testosterone? 

A new study of 2,161 men 20 years & older examined the relationship between age, testosterone levels and a number of chronic conditions. The study particularly focused on nine chronic conditions including, cardiovascular disease, depression, hypertension, high cholesterol, high triglycerides, lung disease, stroke and type 2 diabetes. 

The study divided men into three groups:

  • Young men-20 to 40 years old
  • Middle-aged men-40-60 years old
  • Older men-age greater than 60

The study found that in young men and in the older men those with low testosterone levels had a much stronger link to two or more chronic illnesses. The obvious question here is whether the chronic illnesses lead to low testosterone or whether the low testosterone actually contributed to the illnesses. 

Over the past decade there has been a significant increase in various forms of testosterone therapy for males in this category. There are concerns that testosterone therapy may accelerate the growth of prostate cancer and some researchers have even linked higher testosterone levels to atherosclerosis (the progressive build-up of fat, inflammatory tissue and calcification in the walls of arteries leading to heart attack and stroke). But, other evidence points to the fact that testosterone therapy may improve metabolic syndrome (tendency to diabetes, high blood pressure, cholesterol abnormalities and abdominal fat) and thus possibly reduce the risk for a variety of conditions that can be linked to increased risk for cardiovascular disease and possibly even cancer. 

As with most subjects in medicine there are often varying and opposing views and most conservative experts in the area would suggest caution in using therapies that do not have robust long-term data. But, many men suffer, typically in silence, from the symptoms of andropause and with the variety of testosterone therapies which typically involve weekly injections or testosterone implants or the more user friendly testosterone creams, many of the symptoms of andropause are well managed and markedly improve the person’s quality of life. My strong advice in this area is to have a proper and extensive medical workup before commencing any of these therapies.

Regardless, it certainly appears that reducing levels of testosterone as we age are of no benefit and with proper monitoring and appropriate therapy this may be managed with a very good end result.



Are Omega-3 supplements a waste of money?

Friday, May 04, 2018


A recent piece published in the Australian newspaper reviewed a scientific article recently published on this issue. This particular article was a meta-analysis of 10 randomised controlled trials involving just under 78,000 people average age 64, all at significant risk for heart disease. As these were different trials in somewhat different populations there were varying doses of omega three fatty acids ranging from 226 mg per day up to 1800 mg per day.

The average length of these 10 trials was only 4.4 years with only one of the 10 trials going beyond five years. This meta-analysis showed no benefits whatsoever, as far as statistics are concerned, from supplementing with omega three fatty acids. Thus, should we clear out our cupboards and ignore all of the very good evidence accumulated over the years purely because one particular study tells us that there is no benefit?

Firstly, without wishing to sound too pedantic, the journalist writing this article couldn’t even quote the correct journal where the article was published. The journalist said it came from the Journal of the American College of Cardiology when, in fact, it was published in the Journal of the American Medical Association-Cardiology Journal. A minor point, but still important when you review the overall results and their implications.

Here now is the major issue. The Mayo Clinic in the January 2017 Mayo Clinic proceedings published a large meta-analysis showing the short-term randomised controlled trials i.e. shorter than five years, showed no benefits from fish oil supplementation. But the longer trials (which admittedly were not randomised i.e. there were no placebo groups, purely the comparison of people who did or did not take fish oil) showed that the ingestion of omega three fatty acids beyond five years led to a statistically significant 18% reduction in cardiovascular disease risk. 

The very long term studies of fish consumption which in some cases have been followed for over 30 years have shown on average around a 30% reduction in cardiovascular disease in the people who had 2 to 3 fish meals per week. A large meta-analysis published by Hooper et al in 2004 again suggested no benefit from either the intake of fish or omega-3 supplementation.

Again, the longer term trials were ignored because the short term trials negated the benefits purely by more numbers in the short-term trials. Also, over the past decade or so there has been increasing concern around fish consumption because of the heavily polluted shipping corridors in the northern hemisphere leading to significant levels of dioxins and methylmercury found in fish from these areas. 

As I have stated on numerous occasions, short-term supplementation whether it be omega 3 supplementation, multivitamin or the vast majority of supplements available is of no great value because the supplements do not have the strong effects of pharmaceutical agents and should be considered supplements to a healthy lifestyle. Again, the benefits of dietary interventions, exercise, high quality sleep or the cessation of smoking, to name a few healthy lifestyle practices showed benefits over a number of years but minimal benefits in terms of cardiovascular death and morbidity over a short period of time. 

I see supplementation somewhat like paying insurance. You may not be benefiting right now from doing so but if you have a problem in the future that’s when you will see the benefits from having paid your regular insurance bill. With supplements, you won’t feel better, you won’t prevent a heart attack in the short-term but anything beyond five years have shown benefits, proven in a variety of different studies.

To quote “the Donald”, I believe studies such as the one reported in the Australian are just another example of fake news that should be ignored.



Is a personalised cancer vaccine the answer?

Thursday, May 03, 2018

Over the past decade we have seen enormous strides in the management of cancer. There have been a number of different approaches, including immunotherapy, which has seen some previously unmanageable diseases demonstrate prolonged remission, and in some cases, a cure.

One of the major problems with treating cancers is that the genetic make-up of an individual cancer is completely different between individuals. It has been suggested by some scientists, for example, that breast cancer is over 200 different diseases all bundled into the one diagnosis. Therefore, it is more logical to target each individual with therapy directed at their own particular cancer and its individualised personalised genetic makeup.

A recent small but very powerful study published in Science Translational Medicine treated 25 women with advanced ovarian cancer. These woman had been through standard chemotherapy and surgery. Stage IV ovarian cancer has a 17%, five-year survival, making it one of the worst forms of cancer in the world.

This treatment regimen involved particular cells in the body known as dendritic cells which are basically the messengers that take up the antigen, which are the spikes on a tumour that give the personalised signature for that particular cancer. These dendritic cells are removed from the blood of the patient, are exposed to tumour extracts and then a chemical known as interferon gamma, which activates the immune response is then injected into the patient’s lymph nodes. These 25 women had the harvested dendritic cells injected every 3 weeks and most treatments continued for up to 2 years.

Around half the patients experienced a significant T-cell response to the individualised tumour and these responders survive longer with no tumour progression compared with the non-responders. In fact, the two-year overall survival rate in the responder group was 100% whereas it was only 25% in the non-responders.

One case study of a 46-year-old woman who had undergone 5 courses of chemotherapy for advanced ovarian cancer and was considered stage IV at the start of the trial had 28 doses of personalised vaccine over 2 years and has remained cancer free for 5 years.

Another approach used this time for lymphoma is known as CAR-T cell cancer treatment. This involves collecting the patient’s own T cells and genetically modifying them in the laboratory including a gene to instruct the cells to target and kill the specific cancer involved. These T cells are then infused back into the patients. A study published in the December 10, 2017 New England Journal of Medicine treated patients who had already failed standard therapy for lymphoma. 111 patients were given CAR-T treatment. 42% of the patients were in complete remission after a follow up of around 15 months. They were, however, quite significant side effects from this therapy but the results are very promising.

Regardless, it appears that medical science is edging closer to a cure for cancer which was once typically a death sentence.


Vitamins - are they a load of hype?

Thursday, April 26, 2018


For many years there has been a raging debate between conservative medical researchers and the complementary medical world around vitamin supplementation. The argument presented by conservative medicine is that we obtain all of the vitamins we need from a modern diet and we no longer see deficiency diseases to any great extent.

The second component of the argument is that the vast majority of randomised controlled clinical trials using vitamin supplementation have not demonstrated any clinical benefit, and in some cases, have even trended towards some degree of harm.

But, there is a strong argument against this position for the following reasons: 


  1. Less than 10% of modern society ingests 2-3 pieces of fruit per day and 3-5 servings of vegetables per day which is the recommended dosage of our major source of micro nutrients. Thus, the majority of people living in the modern world do not get an adequate amount of vitamins, minerals and trace metals from their diet.
  2.  Most of the randomised controlled clinical trials have a follow up period of 5 years or less. This may be adequate for strong synthetic drugs but for lifestyle interventions or natural supplements is not really long enough to show a significant clinical benefit. I make the analogy between a high performance motor car and a bicycle. A high performance motor car will get you from A to B very quickly but with the potential for an accident causing harm and possibly death and thus the need for seat belts, safety mechanisms within the car and very strong road rules to minimise harm. Lifestyle interventions and natural supplements are like a bicycle. It takes much longer to get from A to B but you also get some exercise along the way and the rules and safety precautions for the bicycle do not need to be anywhere near as rigid as for the high performance motor car. As we know too well in this society, the only issues arise when we combine the motorcar and the bicycle on the same road. Thus the concern about interactions between pharmaceuticals and some supplements. Randomised control trials are thus very important for drugs and medical procedures because of the stronger effects and stronger potential for harm but trends in clinical benefits and also improvements in surrogate markers are all that is necessary for natural supplements for all of the above reasons.
  3. All vitamins are not created equal. In Australia, natural supplements are made to pharmaceutical standards and thus what it says on the bottle is actually in the bottle and there are no contaminants. American supplements are made to food standards and thus there is a stronger potential for contaminants and for inaccurate dosing. This, of course, is not always the case but it is always better to source of vitamins that have been made to pharmaceutical grade.
  4. Vitamin supplements are just that i.e. supplements. Supplements are not strong enough to work against poor lifestyle habits. This has been shown clearly when comparing two major supplement studies performed in the United States. The first study, the Iowa women’s study showed no benefit and possibly a mild detriment from taking a multivitamin daily for a follow-up of 19 years. Iowa is typically a working class area with many people practising poor dietary habits. The nurses’ health study & the male physician’s trial from the more affluent Boston area has shown significant benefits from the long-term ingestion of a daily Multivitamins. Up to 10 years of taking a Multivitamin on a daily basis showed no actual benefit. In the physicians who took a Multivitamin for 10 years or more there was an 8% reduction in common cancers and cataracts and then when the data was analysed at 20 years there was a 44% reduction in cardiovascular disease. The observational data in the nurses at 15 years showed a 75% reduction in bowel cancer, 25% reduction in breast cancer and a 23% reduction in cardiovascular disease. A recent meta-analysis published in Mayo Clinic proceedings in January 2017 looking at Omega 3 supplementation showed no benefit in the trials up to 5 years but in the trials beyond 5 years an 18% reduction in cardiovascular disease.
  5. Many other supplements have been studied with significant benefits in surrogate markers. For example, taking natural vitamin E (D-alpha tocopherol) with vitamin C in 2 trials-IVUS, ASAP showed a 25% reduction in atherosclerosis seen using carotid Dopplers. There is also excellent work assessing a variety of surrogate markers with Bergamot polyphenolic fraction, ubiquinol, vitamin K 2 and kyolic age garlic.
  6. Any studies that have suggested no significant benefit or possibly harm have used poor quality, synthetic supplements or had too short a trial length or attempted to correct abnormalities in people with advanced disease i.e. too little too late.

 The problem with this entire debate is the difference of opinion between reductionist scientists and those who take a more global, open-minded view. I am reminded of the analogy of the 3 blind men at an elephant.

One man describes the tusks, another the trunk and another the tail but is it not better to look at the entire elephant. When you examine the long-term benefits for supplementation, in my view, these are very clear but do require a long-term commitment to swallowing pills or potions not recommended by mainstream medicine. At the worst, you are blowing your money but at the best you are gaining extra benefits to living a healthy lifestyle.

Fortunately, at this stage, it is your choice and does not require a regular prescription from a member of the medical profession.



Alcohol - how much should we drink?

Wednesday, April 18, 2018


For many years there has been this ongoing debate in society regarding the potential health detriments, along with the possible health benefits, of consuming alcohol. Much of the evidence points to a J shaped curve suggesting 1-2 standard drinks per day may even confer some health benefit compared with those people who are teetotallers. 

The argument given by those people opposed to any alcohol consumption is that often the non-drinkers in society were previous heavy drinkers, or even alcoholics, and the prior damage caused to their body from alcohol made the non-drinking group look sicker than they otherwise would have been because of the prior drinkers being included.

There is no dispute that consuming consistently more than 3 standard alcoholic drinks on a daily basis is associated with a number of health detriments, and in particular alcohol-related liver disease, varying forms of cerebral degeneration, along with atrial fibrillation and even dilated cardiomyopathy. There is also a strong link to peripheral neuropathy and many cancers. 

A recent extensive trial published in the Lancet looked at just under 600,000 people from 19 developed countries around the world with records often dating back to 1964. There were 11,000 Australians in this trial.

The key findings here related to the consumption of standard drinks over a week. So we can be clear about what is a standard drink, 375 mls of full strength beer (4.8% alcohol) is equivalent to 1.4 standard drinks. 150 mls of wine (13.5% alcohol) is equivalent to 1.5 standard drinks. 30 mls of spirits (40% alcohol) is the equivalent of 0.95% standard drinks.

The lowest death rates in the study were in people who consumed less than 10 standard drinks per week. Those that consumed 10-20 standard drinks per week reduced life expectancy by 6 months. Greater than 35 standard drinks per week reduced life expectancy by 4-5 years. It was found that having 2 cans of beer per day increased death risk by around 5%, whereas greater than 21 cans of beer per day increased death risk by 20%.

Although I believe it is highly irresponsible for any doctor to encourage people to drink, I also believe it is important to have a more global view of the science. The vast majority of studies looking at alcohol consumption come from non-Mediterranean Europe, America and Australia. The problem here is that there is no separation between alcohol consumption and, often, poor dietary habits. For example, if you examine the standard American diet and add alcohol there are certainly no benefits. And now, with this new information, probably significant detriments. But, studies performed in the more affluent Boston area known as the Male Physicians trial showed that one standard glass of red wine per day reduced sudden cardiac death by 80%. Probably even more compelling is all of the data from Mediterranean countries showing the low-dose consumption of alcohol (on average 2 standard drinks typically of red wine per day) is associated with a 50% reduction in heart disease and cancer.

Data, again from Boston, this time from the Nurses Health study, a 30-year study from Harvard University has shown that women who consume one to two glasses of wine per day may increase their breast cancer risk but taking a daily Multivitamin negates this risk if the vitamin is consumed for 15 years or more.

Thus, although I am not suggesting alcohol is a health tonic, low-dose consumption may offer some health benefits only if combined with healthy eating. This new data, although compelling and should not be ignored, should be put into perspective. As with most suggestions, moderation in all things.



Viagra - some more hard evidence for its benefits

Thursday, April 05, 2018


Around 20 years ago, Viagra and two other erectile dysfunction agents hit the medical market, becoming one of the most widely used pharmaceutical drug agents across the globe. These drugs, known as phosphodiesterase inhibitors (PDE-5 inhibitors) were initially trialled as cardiac drugs because they open up arteries. 

When middle-aged males with heart disease in the initial trials asked the researchers for more of these wonder drugs, it was clear they were more than just a tonic for the heart. Once the researchers discovered the increase in sexual performance for middle-aged and older men, where erectile dysfunction is commonplace, a blockbuster drug for Pfizer hit the public and the rest is history. 

The PDE-5 inhibitors work by opening up the arteries to what many males consider the most important organ and thus give (for many men), much stronger erections. But, soon after their release around 20 years ago, with the widespread use of these agents, there were a few deaths reported, raising the concern that there may be some hitherto unknown side-effects from these drugs which could be lethal. 

But, with further research, it was concluded that the handful of reported deaths were the result of the excess physical activity that Viagra, Cialis and Levitra encourage and not the drug itself. There is no doubt that people with serious heart disease should not be engaging in sexual activity unless they have been given full clearance by their cardiologist. Men with heart disease also suffer erectile dysfunction, which in some cases may be the presenting symptom of a heart problem. That is precisely why any person over the age of 50 who wants to engage in vigorous activity of any kind, whether it be sexual or standard exercise, should have some form of cardiovascular assessment. I would suggest a coronary calcium score and stress echocardiogram. 

But, now for the good news. A study released in 2017 reviewed the records 43,000 men, 80 years and younger following a hospital admission for heart attack. They were followed for just over three years after their hospital admission. Those patients who were prescribed one of the three PDE-5 inhibitors, Viagra, Cialis and Levitra, were a third less likely to die and 40% less likely to be hospitalised with heart failure. The study clearly showed that these drugs are not only beneficial for enhancing erectile function but are also good for the heart. There has also been some work showing benefits in a less common condition known as primary pulmonary hypertension. 

The most recent trial, released by Augusta University in Georgia in America has suggested that Viagra reduces colorectal cancer in a mouse model of colon cancer. This study suggested a 50% reduction in the formation of colonic tumours. Whilst the study was only performed in mice, it adds to the body of evidence that whilst enhancing male sexual performance, PDE-5 inhibitors may also be beneficial in a number of other conditions. 

So, the next time you swallow your Viagra, don’t see it as a naughty indulgence, see it as therapy.



A chocolate a day...

Tuesday, April 03, 2018

by Ross Walker

Did you consume too much chocolate over the weekend? If so, don't fret!

Not all chocolate is created equal. The real benefit comes from dark chocolate and,in particular, a set of chemicals called flavonoids from the polyphenol set of compounds. These flavonoids come from the seed of the cacao plant, the basic source of chocolate. The more processed the chocolate, i.e. milk chocolate, the less the health benefits.

Recent studies involving various forms of cocoa related products show a reduction in:

1. Stroke – recently at the conference of the American Academy of Neurology, a paper was presented following 44,000 people for a number of years. Those who had a weekly serving of dark chocolate had a 22% reduction in stroke.

A paper from 2008 showed that a small amount of a dark chocolate on a daily basis reduces inflammatory markers in the bloodstream which are commonly associated with the risk for heart disease and cancer but also they showed a reduction in blood pressure, coronary plaque formation and improved blood flow. An added benefit was also a minor degree of thinning of the blood.

But, these effects were only demonstrated with chocolate based products that were high in cocoa solids, (preferably 70% or greater and only in low doses). Also, it is important to state that the benefits were only small. The best cocoa solid is natural, unsweetened cocoa powder and second is the bittersweet or semi sweet dark chocolate (preferably with the 70% mark on the packet).

The Walker suggested dose is one small square on a daily basis, which equates to a half a 100gram bar per week.

But, don’t forget the fat and sugar content of chocolate. Chocolate is around one third fat and 50% sugar. So, your average 50 gram chocolate bar is 15 grams of fat and 25 grams of sugar which adds up to 264 calories.

That is almost a brisk half an hour walk to burn off that amount of calories.

So, the next time you hear that chocolate is a health food, remember that not all chocolate is created equal.


Are low calorie sweeteners safe for you?

Thursday, March 22, 2018

The commonest syndrome in the world is metabolic syndrome. The metabolic syndrome is directly related to a genetic condition known as insulin resistance. Insulin resistance occurs in 30% of Caucasians, 50% of Asians and close to 100% of people with darker skin. Insulin resistance is associated with tendency to, or frank diabetes, hypertension, cholesterol abnormalities characterise by high triglycerides levels and low HDL (the so-called good cholesterol), abdominal obesity and increased risk for cardiovascular disease. 


Two or more of these insulin resistance associated conditions being defined as metabolic syndrome. The reality is that well over 1 billion people on the planet have this condition. Being insulin resistant is a survival advantage if you are a hunter gatherer. Why? Because you are a more efficient fat storer for the times when food is not freely available. Also, as a hunter gatherer you are constantly moving, searching for food. Bring in the modern world where we typically are sitting on our backsides all day in sedentary jobs, spending far too much time watching television, along with breakfast lunch and dinner with often snacks in between. 

Being insulin resistant in the modern environment makes it very easy to gain weight. Insulin basically assists the entry of nutrients into healthy cells and when you are insulin resistant, the pancreas has to make more insulin to push the nutrients into your cells. After years of doing so in a modern environment, the pancreas starts to fail, thus pre-diabetes and diabetes. This also leads to high blood pressure and the cholesterol issues I have mentioned and it is also very easy to put on fat around the belly. Abdominal fat is not only an ugly lump of lard but also a toxic reservoir holding on to synthetic chemicals through lifetime exposure. This also creates the vicious circle of more insulin resistance and therefore more metabolic syndrome. 


A study just released from George Washington University in Washington DC studied the effects of low calorie sweeteners and metabolic syndrome. They specifically looked at the low-calorie sweetener, Sucralose and found that when human fat cells are exposed to relatively high quantities of low-calorie sweetener, simulating the human experience, this stimulates abdominal fat stem cells to express genes that are linked directly with the production of fat and inflammation. They followed up this component of the study with biopsies of abdominal fat from people who were regular consumers of low-calorie sweeteners. 

Interestingly, those people who were healthy weight and consumed low-calorie sweeteners did not have an increased gene expression in the stem cells but the overweight and obese people had a marked increase in gene expression therefore leading to excessive fat production and inflammation. 

I’m not suggesting that healthy weight people should be consuming any form of soft drink purely stating that those people who already achieved overweight and/or obesity are further along the spectrum and have now entered the vicious cycle of insulin resistance begetting insulin resistance and metabolic syndrome making metabolic syndrome worse. 

There is no doubt that metabolic syndrome is the major epidemic of the 21st-century and until we start learning to treat our bodies better we will continue to see rampaging cardiovascular disease, diabetes and cancer, all consequences of metabolic syndrome.


Exercise - Is more really better?

Thursday, March 15, 2018

Since the recent death of Steve Folkes at the age of 59, still incredibly fit and a regular exerciser, along with the sudden death of the 31-year-old Italian soccer player, Davide Astori, many questions have been raised about the role of exercise and its ability to prevent cardiovascular disease.

In my professional talks, I have a slide with the picture of Jim Fixx next to a picture of Winston Churchill. Jim Fixx wrote the complete book of running, didn’t have an ounce of body fat and had completed multiple marathons. He died in a race at of the age 53. Winston Churchill, smoked,  drank, was overweight and depressed and died at the age of 91. I have recently completed a lecture series titled “Cardiovascular disease - it’s your genes that loads the gun and your environment that pulls the trigger”.

The reality is that all cardiovascular disease has an element of genetics, and those with the more severe genetic abnormalities may still die earlier despite exquisite lifestyle principles.

I have repeatedly suggested that the ideal amount of exercise every week is somewhere between three to five hours. So, is this just my gut feeling or is there any good evidence for these comments?


A recent, long term study of 25 years followed just over 5,100 people aged between 18 to 30 years old at the entry of the study. For various reasons, the final analysis reviewed 3,175 participants who had undergone eight examinations over the 25 year period and answered at least three questionnaires regarding the amount of exercise they performed along with other lifestyle factors as well.

A coronary calcium score was performed at some stage between age 43 to 55 and the participants were divided into three groups

  1. Those who exercised less than 2 ½ hours per week
  2. Those who exercised between 3 to 5 hours per week
  3. Those who exercised more than 7 1/2 hours per week.

The results were quite surprising and in many ways, somewhat disturbing. When the group who exercised more than 7 1/2 hours were compared to the other groups there was a 27% increase in coronary artery calcification, suggesting lack of protection from heavy exercise for heart disease risk.

Interestingly, and somewhat difficult to explain, is the fact that white males in the third group had an 86% increased risk for coronary artery calcification. The higher level exercise group, for some reason, did not appear to affect cardiac risk in black men or all women. Although there is no clear explanation for this difference, I propose the following explanations.


Atherosclerosis, which is the progressive build-up of fat, inflammatory tissue and calcium in the walls of arteries, tends to occur later in women (on average 10 years) and a coronary calcium score performed between age 43 to 55 is too early to detect significant atherosclerosis in a female population.

People who exercise for more than 7 1/2 hours per week are typically (although not always) joggers or cyclists, or professional athletes. There is no doubt that African Americans do make up a significant proportion of the high-level athletes in America, not to mention the Africans who tend to win most of the marathons. It could be that people with darker skin are more physiologically adapted to exercise for longer periods and thus have less evidence of cardiovascular disease.

Regardless, it does appear for those of us who are not professional athletes (i.e. sport being their major source of income), that if you are exercising for good health, the 3-5 hour dose per week appears to be the healthiest level.


The second study was fascinating in that it looked at the type of exercise which may be important for specific disease prevention. There are two basic types of exercise, aerobic - cardio, or anaerobic - strength and resistance training. This study of 80,000 people, older than 30 years, commenced in 1994 and continued until 2008 with an average follow-up of around nine years. It looked at strength and resistance training for 50 to 60 minutes per week as opposed to moderate intensity exercise 50 minutes per week e.g. walking, as opposed to high-intensity exercise such as running or cycling for 75 minutes per week.

In all these groups, compared with people who were inactive, there was around an 18% lower risk of early death purely by performing the various types of exercise. But, with resistance & strength training there was a 31% reduced cancer risk, whereas with aerobic exercise there was a 21% reduction in cardiovascular risk. The reduction in cancer death has been repeated in a number of studies in people who regularly perform some form of resistance training.

My suggested reason for this is that cardio exercise improves cardiovascular efficiency through more efficient pumping of the heart and better blood flow to muscles. Because of the more efficient cardiovascular system there is logically a reduction in cardiovascular death. Interestingly, strength and resistance training increases the fitness and size of muscles, thus improving muscle metabolism and requiring a much higher level of blood flow to the muscles. Logically, this would redirect blood flow away from tumours and thus help prevent cancer death.


A study in the American Journal of Preventive Medicine reviewed 140,000 people participating in the Cancer Prevention Study II Nutrition cohort. It found that as little as two hours per week of walking, compared with those who did no exercise, reduced overall death risk from all causes. Those who performed the recommended 150 minutes of walking demonstrated a 20% reduction in all-cause death. Interestingly, those who walked for more than six hours per week had a 35% reduction in death related to respiratory causes, a 20% reduction in cardiovascular death and a 9% reduction in cancer death.


A study from the Journal, Circulation reviewed one hundred and 52 middle-aged endurance athletes with an average age of 55 and compare these people with normal activity age matched controls. All participants in the study had no prior history of coronary heart disease or any other significant risk factors. A CT coronary angiogram was performed and in both groups 60% demonstrated no significant coronary artery disease. But, in the athletes there was double the amount of coronary plaque compared with those who performed normal activity. Those in the highest risk group had a direct relationship to the amount of years of training i.e. the more exercise the higher the risk.

Another study looked at males older than 45 again with an average age of 55 and show that 53% of these athletes had coronary artery calcification. Again, the more activity performed, the higher the coronary artery calcification and thus, an higher atherosclerotic burden.

Studies performed on marathon runners have shown that a third had elevated levels of troponin, a marker of heart damage, along with echocardiographyic changes in the right ventricle at the end of the marathon.

Possible explanations for this are that:

  1. Many high-level exercisers have the delusion that because they perform so much exercise they can eat what they like which can still lead to significant cardiac issues
  2. A study from many years ago published in the New England Journal of Medicine review the psychological profile of Marathon on runners and found this was very similar to people with anorexia nervosa. This is a condition which is also associated with sudden cardiac death
  3. Possibly, the reason many people take up endurance running is because of a poor family history, a game with the delusion that they can out run their genetics
  4. Another minor explanation is that many high-level athletes suffer recurrence musculoskeletal issues often requiring anti-inflammatory medications which have been associated with a higher risk for cardiac disease.


Probably the most disturbing statistic from all the studies is that 27% of people are inactive and only 50% of people meet the guidelines for recommended exercise.

I have stated on numerous occasions that exercise is the second best drug on the planet after happiness but it also appears that the correct dose of exercise is important along with the type of exercise to reduce specific conditions. This is why I constantly say that the suggested dose is 3-5 hours per week which should be divided into two thirds cardio and one third resistance training. Just as the real estate agents say the most important principle is “location, location and location”, those of us involved in preventative medicine state “movement, movement and movement”.



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