Recent news in the prevention of diabetes is that weight training and yoga help decrease the risk of diabetes in women who have already been diagnosed with pre-diabetes. Although it does not appear to be as effective as cardio exercise, such as biking, jogging or swimming in that regard,it’s good to know it provides additional benefit. This was culled from the Nurses Health Study, that massive collection of data that pointed to potentially harmful effects of post-menopausal hormones. We can now add this information about prevention of diabetes to the large body of evidence we have that shows that both cardio and resistance exercises help control the blood sugar once diabetes is full-blown.
Remarkably, 35% of the US population has ‘pre-diabetes’, which we’ll define in a minute. From this stage, over the next 10 years or so, up to 70% will eventually be diagnosed with diabetes. But why wait for diabetes to occur, when the progression from diabetes can be stopped in 40% of people with
150 minutes of cardio (aerobic exercise) weekly, or in 67% when 150 minutes of cardio is combined with one hour per week of muscle strengthening
and conditioning. Exercise is more effective than any medication available. So pre-diabetics shouldn’t just follow the road to diabetes – start making that U-turn now!
Pre-diabetes is present if any one of the following lab results is found. The risk of going from pre diabetes to diabetes is especially high when someone
has more than one of these prediabetes- defining factors:
- a high fasting glucose of 100-125 (also known as Impaired Fasting Glucose, IFG);
- a high blood sugar 2 hours after a 75 gm glucose load of 140-199 (also known as Impaired Glucose Tolerance, IGT); and/or
- an elevated average sugar over the past 4-6 weeks as measured by a hemoglobic A1C (HbA1c) of 5.7 – 6.4.
The blood sugar is normally controlled by insulin, a hormone released by the beta cells of the pancreas. In diabetes, there is poor sugar control
because the liver breaks down glycogen stores to create too much glucose, even when the body doesn’t need it. So sugar is high even after an
overnight fast. Also, the fat and muscle cells that need to take up glucose and remove it from the bloodstream become more resistant to the action of
insulin. The pancreas works harder and harder to keep up with the excess need for insulin, but eventually can’t release enough insulin to keep up and
the blood sugar rises. Exercise helps in several ways. It helps the muscle cells use more glucose and helps the active cells to take up glucose via different pathways that do not require insulin. Also, any weight loss associated with the exercise improves liver function and insulin sensitivity, so the body is better able to maintain a normal blood sugar.
In the past, several studies involving hundreds of thousands of individuals showed that cardio exercise greatly decreased the risk of diabetes, even in
people who already had pre-diabetes, and improved blood sugar control in those with diabetes. The reason that many patients are told to exercise 30
minutes a day at least 5 days a week, is that these studies showed that any amount of exercise is good, more is better, and that there is a steady significant improvement in blood sugars as one increases exercise from zero to 150 minutes per week. Even more exercise is beneficial, but the slope flattens out so that the added benefit of the extra minutes above 150 is not that great. The extra perk of doing cardio is that in addition to avoiding diabetes, the exercise also reduces the risk of heart disease, stroke, high cholesterol and cancer and decreases weight.
In the Nurses Health Study mentioned at the beginning of the article, about 100,000 women were classified as taking part in:
- muscle strengthening with weights
- lower intensity muscle conditioning (yoga or toning exercises) and/or
- aerobic moderate to vigorous physical activity.
They found that muscle strengthening and conditioning did decrease the risk of development of diabetes by as much as 25% if practiced 2.5 hours a
week. The same amount of time spent on cardio can reduce the risk of diabetes even more, but the most important factor in deciding on which exercise
to do is that you find it enjoyable, and are likely to keep with it. In addition to decreasing the risk of diabetes, the use of weights and yoga/ toning exercises help decrease the risk of osteoporosis and increase balance, thereby preventing falls and fractures.
Dietary changes that can help reduce diabetes include decreasing saturated fats and sweets, and increasing insoluble dietary fiber and whole grains. These changes may improve the sensitivity of the muscle to insulin – i.e. the muscles might respond better to the presence of insulin. In some cases, as little as 2% weight loss (e.g. 4 pounds in a 200 pound person) can improve the liver’s response to insulin.
Pre-diabetes is such a common problem and intervention with improved nutrition and exercise is so effective, that everyone with any risk factors for diabetes should be aware of their blood sugar. Risk factors include being overweight or inactive, having a family history of diabetes, high blood pressure or heart disease, being of high risk race/ethnicity (African American, Latino, Native American or Asian American), having had diabetes during pregnancy, or having delivered a large baby. Sadly, we are seeing more type 2 diabetes diagnosed in teens and young adults because of the obesity epidemic. In my practice, I routinely run a fasting blood sugar (FBS) at yearly physicals, and run a long-term blood sugar (HbA1c) when the FBS is elevated or I have a higher suspicion of diabetes. Be sure you know what your blood sugar is and that you are doing everything you can to avoid diabetes, or to treat it when it arises, to avoid the complications such as heart attack, stroke, impaired circulation and vision, and kidney failure.
With 1/3 of the US population having pre-diabetes, chances are that you or one of your friends or relatives carries this diagnosis. If you or they find yourselves promising yourself year after year that you will increase exercise, change your food intake, etc, but never seem to accomplish your goal, now make it a top priority. Preventing diabetes now can avoid major changes in the future. As Jody asked you to do regarding your New Years Resolutions, examine why you have been unsuccessful in the past, aim to make just one change in your activity and one change in your nutrition and re-assess in another few weeks. Your long term health depends on it!
http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1001587-referenced on NPR in January 2014 Muscle-Strengthening and Conditioning Activities and Risk of Type 2 Diabetes: A Prospective Study in Two Cohorts of US Women, Anders Grøntved et al. Jan 14, 2014
http://www.cdc.gov/physicalactivity/everyone/guidelines/index.html – how much physical activity do you need? on CDC website