A study from New Zealand shows that walking 10 minutes after meals lowers high blood sugar by more than 22 percent in diabetics, which is more effective than 30 minutes of exercise done once a day (Diabetologia, October 17, 2016). This agrees with other studies that show that exercising after meals helps to treat and prevent diabetes (Am Med Dir Assoc, July 2009;10(6):394-397). Another study shows that walking up and down stairs for just three minutes after a meal dramatically lowers blood sugar in diabetics (BMJ Open Diab Res Care, July 25, 2016;4(1):e000232).
A review of 28 published studies covering more than 1.2 million people, of which 82,000 developed type 2 diabetes, showed that the more people exercise, the lower their risk of developing diabetes (Diabetologia, October 17, 2016).
Exercise lowers high blood sugar by making the cells respond more effectively to insulin to drive sugar from the bloodstream into muscles. People who doubled their exercise time, from 150 to 300 minutes per week, reduced their risk of developing diabetes by 36 percent. More than 40 percent of North Americans have high blood sugar levels, to a large degree because fewer than 50 percent exercise at least 30 minutes a day, five days a week.
Intense Exercise Is More Effective and Takes Less Time
Intense interval exercise reduces high blood sugar levels more effectively than more casual exercise and takes less time. In one study, diabetics exercised a total of just six sessions of 10 intervals (60 seconds of hard pedaling followed by a short rest between each interval) on a stationary bike. The workouts took only 20 minutes per session, three times a week for two weeks, for a total of just two hours of exercise.
After two weeks, they had reduced their average 24-hour blood sugar and 3-hours-after-eating blood sugar levels, and increased muscle mitochondrial capacity that controls blood sugar levels (Journal of Applied Physiology, December 1, 2011;111(6):1554-1560). Warning: Diabetics are at increased risk for having blocked arteries leading to the heart, so they need to check with their doctor before increasing the amount and intensity of their exercise program.
Why Resting After Eating Raises Blood Sugar
After eating, always try to move about and do not lie down (Diabetes Research and Clinical Practice, September 2007;77(3):S87–S91)). Your blood sugar virtually always rises after you eat anything. If it rises too high, sugar can stick irreversibly to the outer membranes of cells throughout your body to destroy them. This cell destruction causes virtually all of the miserable consequences of diabetes: blindness, dementia, loss of feeling and so forth. Resting muscles draw almost no sugar from your bloodstream, and to draw any sugar, they need insulin.
However, contracting muscles draw large amounts of sugar from the bloodstream and don’t even need insulin to do so. Any muscle contraction changes a muscle from needing insulin to pull sugar from your bloodstream to not needing insulin, and therefore removes large amounts of sugar from your bloodstream.
High rises in blood sugar after meals markedly increase your chances of gaining weight, developing diabetes and certain cancers, and suffering a heart attack. More than 40 percent of North American adults already have metabolic syndrome or diabetes and already have cell damage from high rises in blood sugar after meals. The older you are, the more likely you are to already have cell damage. The later you eat at night, the more likely you are to lie down after eating to increase your risk for cell damage.
My Recommendations
- Eat early in the day so you are still active after meals; avoid eating just before you go to bed.
- Try to move your body for at least 20 minutes after you eat.
- Exercise removes more sugar from your bloodstream than just moving around.
- Exercising intensely removes more sugar than exercising at a casual pace.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.
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