There is a period of time in which adequate physical activity can help mediate some of the damage caused by eating an unhealthy meal.
I have discussed related studies before demonstration A single meal high in saturated fat can damage artery function in men, as measured in the arm, but what’s more concerning is blood flow to the heart wall. Researchers randomized men to eat either a high-fat meal that was more than 60% fat, half saturated, with more cholesterol than an egg, or a low-fat meal that was mostly carbohydrates, less than 10% fat, and had 50 times less cholesterol.
Below and at 0:47 in my video Exercise to protect your arteries from junk foodyou can see a Doppler recording of the left anterior descending coronary artery, known as the widow, before the high-fat meal (top). His nice strong signal was compressed within a few hours after eating. the picture (below) was are taken five hours after a high-fat meal.
Coronary flow reserve was reduced after a single high-fat meal, but not after a low-fat meal of the same number of calories.
What does “coronary reserve” means? When part of a coronary artery becomes blocked for any reason, the surrounding vessels dilate. This extra expansion capability is called coronary flow reserveand decreases within hours of eating a fatty meal, undermining the heart’s ability to compensate for clogged arteries. This is how a high-fat meal affects blood flow to the heart.
In extreme cases, you can even witness it’s in the back of one’s eye. Below are before and after images of a retina, which you can also see at 1:34 in my video.
The first image shows milky colored blood vessels and the second shows what happens after a low-fat diet and drugs help remove fat from the bloodstream. Can you see the difference? In the first photo the blood looked like milkshake.
What if you exercise right after eating that high-fat meal? Postprandial inflammation following the extensive rise in blood fat after high-fat meals is a possible explanation for the increased risk of CVD, but substantial evidence suggests that acute exercise is an effective way to clear some of that fat after a meal. However, the beneficial effects of acute exercise on postprandial lipemia (after-meal fatty blood) appear to be relatively short-lived. Going a few days without exercise can completely negate any benefit, no matter how fit you are. The time window appears to be between 18 hours before a meal and about 90 minutes after a meal. And how much exercise do we need? About an hour of moderate-intensity exercise should do it.
In another study, only took 20 minutes of stair climbing, broken up into five minute intervals every hour for four hours after a McDonald’s breakfast of hash browns, eggs, pancakes, an English muffin, sausage and a milkshake. After such a meal, arterial function decreased significantly when the subjects sat down after eating, but not when they did the hour-long stair-climbing exercise. Thus, hourly exercise may moderate the negative effects not only of prolonged sitting but also of eating a high-fat meal, “suggesting that stair climbing should be incorporated as an easily accessible lifestyle strategy for vascular protection. [artery] operation.” Of course, it is understood that the other The way you can protect the function of your arteries is to not eat breakfast at McDonald’s in the first place.
Such a meal would also be have more than 2,000 mg of sodium. That’s more than the 1,500 mg the American Heart Association recommends we stay down for an entire day. Give someone a meal with less salt, even a third less, and this alone can affect the functioning of the arteries within an hour of consumption, even without an increase in blood pressure.
When it comes to blood pressure, some people hectare ‘salt sensitive’, meaning they suffer a big hit in blood pressure when they eat salt, but others are said to be ‘salt tolerant’. Their blood pressure doesn’t really depend much on their salt intake. So, is salt okay for these people? No. High dietary sodium intake reduces arterial function regardless of whether your blood pressure is salt-sensitive or salt-resistant. Your arterial function is impaired either way, going from a low-salt diet to a high-salt diet, which you can see below and at 3:53 in video.
There it is effect of dietary salt beyond blood pressure. Despite the “seemingly unanimous consensus”, some researchers (very often funded by the salt industry) claim that it’s actually not good to cut back on salt, but the evidence is against these naysayers. Like the saturated fat in meat, dairy, and junk, science shows that sodium — not sodium reduction — is “the real bad guy.”
Doctor’s note
This is the second of a three-part series on saturated fat and artery health. The first was How a single meal can cripple your arteries and lungs. It’s next Protect your arteries from saturated fat with these foods.
Still not sold on the dangers of salt? See the evidence that salt raises blood pressure.
