By Gabe Mirkin, M.D.
Everyone should try to exercise every day because exercise helps to prevent diabetes and heart attacks by lowering high blood sugar and stabilizing plaques. A review of 12 studies shows that exercising within three hours after eating lowers blood sugar levels significantly because contracting muscles remove sugar from the bloodstream at a very high rate and don’t even need insulin to do so (Sports Medicine, Feb 2, 2018;1-13). You should never eat just before you go to bed at night, because resting muscles draw almost no sugar from your bloodstream and what little they can draw requires insulin, so the most important time to exercise or just move about is after you eat (Diabetes Research and Clinical Practice, September 2007;77(3):S87–S91).
High Rises in Blood Sugar Damage Cells
Almost 50 percent of North American adults will become diabetic and nearly 30 percent of sudden heart attacks occur in people who have never been told that they are diabetic. A normal fasting blood sugar of less than 100 mg/dl does not rule out diabetes because you can get cell damage if your blood sugar levels rise too high after you eat. Blood sugar levels always rise when you eat, but they should not rise above 140 mg/dl one hour after you eat.
When blood sugar rises too high, it can cause sugar to stick to the outside membranes of every type of cell in your body. Once attached, the sugar can never get off and it is eventually converted to sorbitol that destroys that cell to cause every known side effect of diabetes: blindness, deafness, osteoporosis, dementia, impotence, heart attacks, strokes, certain cancers and so forth (J Biol Chem, Sep 10, 1978;253(17):5985-9). If your blood sugar is above 140 mg/dl one hour after a meal, you are probably suffering cell damage and therefore should be following all the rules for lowering high blood sugar levels (Diabetes Care, 2001;24 (8):1448-1453). See The Hidden Epidemic of Early Diabetes
Exercise Lowers Blood Sugar to Help Prevent and Treat Diabetes
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. You should try to exercise every day, since the ability of contracting muscles to lower blood sugar without needing insulin lasts less than 24 hours (Am J Clin Nutr. 2008(July);88(1):51-57; J Appl Physiol, 2005;99: 338-343 and 2005;8750-7587).
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 repeats of ten 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-hour-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.
Exercise, Gut Bacteria and Inflammation
Recent research shows that both diabetes and heart attacks are caused in part by inflammation, an overactive immunity. See Inflammation Can Help or Harm Your immunity is partially regulated by the 13 trillion bacteria in your colon. The good types of bacteria are happy digesting the food that you eat, but the bad types of bacteria look for other food by trying to invade and puncture the cells lining your colon. Your immunity responds by trying to kill these invading bad bacteria and if your immunity stays on all the time, the same cells and cytokines that kill invading germs attack you to cause inflammation. Studies in humans (Med & Sci Sprts & Exer, Nov 11, 2017 & Gut 2018;67:179–193) and mice (Gut Microbes, Sep 1, 2017; BMC Genomics, 2014 Jun 21;15:511) show that exercise increases the number of good bacteria and decreases the number of bad bacteria in your colon.
Exercise increases the number of mitochondria in your cells that convert food to energy (Ageing Res. Rev, 2008;7:34B42), which increases the available energy for your body. The extra sources of energy increase the number of good colon bacteria that do not need to invade your cells. The increase in good bacteria suppresses the number of bad bacteria, and the good bacteria have enzymes that convert soluble fiber in plants to short chain fatty acids that dampen inflammation (Front. Physiol, May 19, 2017). Just 20 minutes a day of regular exercise can reduce all of the markers of inflammation (Brain, Behavior, and Immunity, Mar 2017;61:60-68; PLOS One, Jan 17, 2018).
Exercise Helps to Stabilize Plaques
The same mechanisms of inflammation that punch holes in the membranes of invading bacteria also punch holes in the inner linings of your arteries to start plaques forming there. Then these same cells and proteins break off a plaque from the inner linings of the arteries leading to your heart to cause bleeding and clotting that can completely obstruct the flow of blood to your heart muscle to cause a heart attack. A pro-inflammatory diet can cause plaques to form, and no amount of exercise prevents plaques from forming. However, many studies show that exercise stabilizes plaques and prevents them from breaking off to cause heart attacks (Circulation, April 27, 2017;136:138-148). Highly-fit older men and woman can have increased numbers of plaques in their arteries, but the plaques are more stable and are the kind that are far less likely to break off to cause heart attacks (Circulation, April 27, 2017;136:138-148; May 2, 2017;136:126-137). Your doctor can find out if the plaques in your arteries are stable by ordering a CT scan of your arteries (Am J of Roentgenology, March 2015;204(3):W249-W260).
• Exercise helps to prevent both diabetes and heart attacks
• Try to exercise every day, since the ability of muscles to draw sugar from your bloodstream without needing insulin lasts less than 24 hours.
• A regular exercise program helps to stabilize plaques so that they are less likely to break off and cause a heart attack. You should also follow an anti-inflammatory diet to limit formation of new plaques in arteries.
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.