December 27, 2011 Leave a comment
by Jeff Horowitz – Smart Training (excerpts also from Wall Street Journal’s Personal Journal)
In case you missed it, an article in the Wall Street Journal’s Personal Journal section of Novemebr 22, “Countdown To a Food Coma”, gave some unexpected support for running and other exercise. The WSJ reported that researchers had found that your body’s reaction to big meals can be an indicater of future heart problems. And interesting for runners, exercise immediately before a big meal — and a regular habit of exercising — can help insulate your body from this harm. Says the WSJ: “Th[e] post-meal recovery period is being studied by scientists who are increasingly finding that what happens in the body after eating a big meal doesn’t just bring on sleepiness, commonly known as food coma. It can also increase the risk of later health problems. “Everybody absorbs fats, sugars and other nutrients differently. These variations can provide clues about a person’s risk for common medical conditions, including heart disease, stroke and diabetes, research shows. Even in healthy people, cells that line the blood vessels temporarily function less efficiently after a person eats a high-fat meal.
“Researchers also are studying strategies for reducing risks in the period immediately after a meal, known as the postprandial phase. While going for a walk after eating might help digestion, for example, recent studies suggest that exercising 12 or more hours before the meal can prevent one of the most damaging effects—a post-meal spike in a type of fat called triglycerides.
One of the biggest tasks for the body after eating is to deal with fats in the blood. Cholesterol, particularly LDL, or “bad” cholesterol, infiltrates the walls of the arteries and forms plaques, which can block blood flow or eventually rupture, leading to heart attack and stroke. The condition is known as atherosclerosis.
“Triglycerides, which typically peak after a big meal, are present in food and are also converted by the body from other nutrients, like carbohydrates. Triglycerides are particularly problematic because they are so good at penetrating the arterial wall.
”In a follow-up study, also published in JAMA, the research team found that testing for elevated triglycerides after eating was a better predictor of future heart attack than measurements taken while a person was fasting, which is the typical method during a checkup. Triglyceride counts after eating also were a more accurate predictor of stroke in women than were cholesterol measurements, according to a study published this year in Annals of Neurology.
Light exercise like a slow walk, done continuously for 30 minutes or more, appears to reduce the peak in triglycerides that occurs after eating a meal some 12 to 16 hours later.
It’s unclear exactly why there is a delay, but exercise induces a number of cellular responses that require different amounts of time before taking effect…Other research has suggested that the benefits of exercise on fat processing can last as long as 48 hours.
The ideal is to be consistently active. But if people are more sedentary and want to time their exercise, it is best to take that long walk half a day before a big meal.