Friday, January 18, 2013
Yes, you CAN be too fit for your own good: Why exercise may be harmful to the heart
A study just published in the journal PLoS One analysed data from six exercise studies involving 1,687 regular exercisers to find out the effects of —regular workouts on the heart.
The results shocked and confused the scientists: in almost one in ten people tested, exercise seemed adversely to affect blood pressure, insulin levels or ‘good’ HDL cholesterol levels.
And in seven per cent of people, not just one but two of these risk factors for heart disease were worse as a result of exercise.
There is no clear explanation for this effect on a small portion of the population, but ‘it’s not a good sign,’ says Claude Bouchard, the study’s lead author and a professor of genetics and nutrition at Louisiana State University.
He suspects it is down to genetics and advises exercisers to have their blood pressure, cholesterol and glucose checked regularly.
Regular amounts of aerobic exercise, such as running, are known to slow the unhealthy changes to the cardiovascular system that occur with age.
However, intense and prolonged endurance training for many years — for instance, for marathons or triathlons — could be damaging to the heart, an editorial review published last year in the British Journal of Sports Medicine suggested.
The author, Greg Whyte, professor of sports science at Liverpool John Moores University, explains: ‘Our research found that 50 per cent of long-term endurance and ultra-endurance runners, some of whom had been training for 43 years, showed signs of heart damage.
‘It is well documented that among veteran athletes there is a higher incidence of early symptoms of cardiac disease, which might increase the risk of a heart attack.
'There is a build-up of collagen in place of heart muscle, and compounds of blood markers that can make someone more susceptible to unusual heart rhythms.
‘It does not occur in people who just do a few marathons during their lifetime, but is a risk in people who have been training long and hard for years.’
So, should you be worried about doing exercise? No, says Professor Whyte, pointing to overwhelming evidence that ‘exercise is wholly beneficial’, not just for the heart but for the whole body.
Even in Bouchard’s study, it was not all bad news. For 10 per cent of people there were enormous gains in at least one measure of heart disease risk, with some improving by up to 50 per cent.
And among those who did have adverse outcomes, there was no evidence that these led to heart attacks or other health problems.
Professor Whyte says: ‘There will always be a few cases of people with underlying health problems and heart issues for whom physical activity can be problematic, but most people should be doing more of it, not less.’
Even ageing long-distance racers should not necessarily hang up their trainers. ‘They may need to be monitored, but the benefits for the heart still outweigh any risks.,’ says Professor Whyte
As for the risk of stroke, most studies say exercise is beneficial for stroke prevention in healthy people, says John Brewer, professor of sport at the University of Bedfordshire.
‘It’s wise to get a check-up if you haven’t exercised for a while or have a family history of heart attacks and strokes, but in general, the evidence suggests that everything from moderate activity to higher-intensity and longer-duration exercise are beneficial.’
Will 50 cloves of garlic kill your cold — or just your love life? Pungent foodstuff may hold key to beating winter illness
In my younger days, I used to chew cloves of garlic if I had a cold. It does help clear the head -- and makes your tongue swell up! -- JR
According to folklore, it keeps vampires at bay. And it will definitely keep your loved ones at arm’s length.
But could a soup made with more than 50 cloves of garlic protect you from colds, flu and even norovirus?
As Britain sneezes and coughs its way through these dark months of contagious nasties, garlic is being hailed for its powers to halt viruses in their tracks.
It has gained its reputation as a virus buster thanks to one of its chemical constituents, allicin.
‘This chemical has been known for a long time for its anti-bacterial and anti-fungal powers,’ says Helen Bond, a Derbyshire-based consultant dietitian and spokeswoman for the British Dietetic Association.
‘Because of this, people assume it is going to boost their immune systems. Lots of people I know are simply mashing up garlic, mixing it with olive oil and spreading it on bread.
‘But how or whether it may actually work has still not been proven categorically.’
Indeed, scientists remain divided on garlic’s ability to combat colds and flu. Last March, a major investigation by the respected global research organisation, the Cochrane Database, found that increasing your garlic intake during winter can cut the duration of cold symptoms — from five-and-a-half days to four-and-a-half.
But the report, which amalgamated all previous scientific studies on garlic, said it could not draw solid conclusions because there is a lack of large-scale, authoritative research.
The problem is that pharmaceutical companies are not interested in running huge, expensive trials — as they would with promising new drug compounds — because there is nothing in garlic that they can patent, package and sell at a profit.
If garlic were found to be a wonder drug, consumers could simply buy it in the supermarket for 30p a bulb or grow their own in the garden.
Nevertheless, garlic has a long and proud tradition as a medicine. The Ancient Egyptians recommended it for 22 ailments. In a papyrus dated 1500 BC, the labourers who built the pyramids ate it to increase their stamina and keep them healthy.
The Ancient Greeks advocated garlic for everything from curing infections, and lung and blood disorders to healing insect bites and even treating leprosy.
The Romans fed it to soldiers and sailors to improve their endurance. Dioscorides, the personal physician to Emperor Nero, wrote a five-volume treatise extolling its virtues.
But it wasn’t until 1858 that the French scientist Louis Pasteur discovered garlic kills bacteria. After placing it in a petri dish full of bacteria, Pasteur noted that within a few days a bacteria-free area had formed around each clove.
More recently, researchers have unearthed evidence to show garlic may help us to stay hale and hearty in a number of ways.
Last June, nutrition scientists at the University of Florida found eating garlic can boost the number of T-cells in the bloodstream. These play a vital role in strengthening our immune systems and fighting viruses.
And pharmacologists at the University of California found that allicin — the active ingredient in garlic that contributes to bad breath — is an infection-killer.
Allicin also makes our blood vessels dilate, improving blood flow and helping to tackle cardiovascular problems such as high cholesterol.
An Australian study of 80 patients published last week in the European Journal of Clinical Nutrition reported that diets high in garlic may reduce high blood pressure.
Posted by jonjayray at 12:26 AM