RSS Feeds

Email a Friend Printer Friendly

Research Reveals Exercise Before Fatty Christmas Meal Helps Curb Bad Effects

December 16, 2004

Research by the British Heart Foundation (BHF) and the University of Glasgow suggests a long walk before your fatty Christmas dinner could help reduce the damage done by the inevitable festive over-indulgence.

Researchers at the University of Glasgow have found that a 90-minute walk lowers fat levels in the blood and improves the function of the blood vessels, even after the walker eats a high-fat, high-carbohydrate meal.

A study led by researcher Dr Jason Gill and funded by the BHF has shown that middle-aged men gain significant benefit from such exercise, and the benefits continue well into the following day. Furthermore, the result is the same whether the man is lean or obese.

The study - which will be published in the Journal of the American College of Cardiology (JACC) on Tuesday 21 December - gives new insight into how exercise works in reducing the build up of fatty deposits in the blood vessels, thereby reducing the risk of coronary heart disease, the UK's biggest killer.

And it might provide valuable advice for those who know they won't be able to resist the temptation of an extra serving of Christmas pudding.

Dr Gill, from the University of Glasgow, said: "Just one brisk walk substantially improved blood vessel function both before and during the hours after eating a fatty meal and the exercise improved the body's handling of dietary fat to the same extent irrespective of whether someone was lean or obese.

"The differences observed in blood fat levels and in blood vessel function after just one workout are remarkable, particularly as these were evident for at least 24 hours after the exercise."

The researchers studied 10 lean and 10 obese middle-aged men. Each man was tested twice for his response to a fatty meal, with the tests performed a week or two apart. On the afternoon before one of the tests, each man walked on a treadmill for 90 minutes. In the control test, no exercise was done.

For both lean and obese men, the exercise was shown to:
·Reduce triglyceride levels (blood fats) by 25% both before and after the fatty meal.
·Improve the function of the endothelium - the inner wall of the blood vessels - by 25% (measured before the meal using laser Doppler imaging)

The endothelium provides an important defence against the build-up of fatty deposits inside the blood vessels, which can disrupt blood flow and lead to a heart attack.

While the benefits of regular physical activity are well established, this study suggests some possible explanations for the protective effects: that exercise can both improve the way the body metabolizes food and help blood vessels resist the harmful effects of fatty foods. This trial also demonstrated that a single exercise session can provide immediate benefits that last at least a day.

"Ninety minutes of exercise is a long time," added Dr Gill. "But it is important to note that the exercise was not strenuous and even obese men, who were unused to exercise, completed the walk without difficulty.

"We appreciate that many people may struggle to fit this much exercise into their busy lives. But 30 minutes of exercise or several smaller bursts of activity are still beneficial. The size of the benefit is related to the number of calories burned during exercise - it is just that if you do twice as much, you will get twice the benefit."

Professor Peter Weissberg, Medical Director of the BHF, said: "Although larger studies are needed to confirm these findings, this study provides clues about the possible mechanisms behind the well-established fact that regular exercise is good for your heart.

"There are no surprises in the fact that eating fatty food increases the amount of fat in your bloodstream - and we would discourage consuming such diets with any regularity. But if you are going to over-eat at Christmas, it would be worth considering going for a good long walk first - as this at least can undo some of the damage the over-indulgence is about to cause."

Glasgow, University of