Just Six Weeks of Exercise Is Enough to Change Both Brain Chemistry and Body Chemistry for the Better; Diets Alone Don’t Have the Same Effect
FOR the person with type 2 diabetes, or the high-risk individual who is trying to prevent the development of diabetes, there is an enormous body of research literature documenting the benefits of exercise.
Unfortunately, there is little data on how to motivate patients to maintain a long term healthy regimen.
Research currently being carried out by scientists at the University of Colorado’s School of Medicine is investigating why exercise feels more difficult for people suffering from type 2 diabetes than it does for people without the disease.
With a recent study showing that under half of all American (and also in other parts of the world, according to anecdotal evidence) with type 2 diabetes take any regular exercise, and that people who do not have diabetes are actually more likely to take exercise, the team hope to pinpoint the reasons why this is.
If this study is able to confirm findings from previous research that revealed that exercise felt harder for those people with diabetes, then it is hoped it will be possible to design specific exercise programs for people with type 2 diabetes.
Indeed, when you can’t move much without discomfort, do-ability is the key to enjoying a workout. Body size is a major factor that is often overlooked. Big-made people can’t do ‘normal’ fitness activities like biking and rowing and weight machines because they’re too uncomfortable. Their bodies get in the way. They can’t bend over, they don’t fit, they can’t run, either — the impact hurts their joints. So they give up on exercise before even trying.
Finding a doable exercise is crucial for obese people because movement is often the key that locks in weight loss. Diets come and go, but exercise sticks, and it prompts the lifestyle changes necessary to shed pound and keep them off, according to Dr. James A. Levine, a Mayo Clinic expert on nutrition and endocrinology.
“There are psychological and chemical advantages of moving over eating,” Levine says. “A diet is a restriction — by definition unpleasant, to be avoided. But when you move it is something you have done and achieved. Every time you do it, you are winning, and feel good about yourself and want to do it again. You not only burn lots of calories, but may be motivated to make better food decisions.”
Research is finding that just six weeks of exercise is enough to change both brain chemistry and body chemistry for the better, he adds. Diets alone don’t have the same effect.
Exercise feeds on itself — once you get moving you might not want to stop. It is essential that all people hoping to slim down find some kind of exercise they can look forward to every day. Options that fit the largest bodies can be surprisingly fun, including walking, water running, swimming, and elliptical training (on wheels or in a gym).
Obese or not, physical exercise is important for all of us. Physical conditioning is one of the most important quality of life factors that we can actually improve, thus contributing to a longer and healthier life. Even better, exercise is empowering since each person can control the amount of activity they do to achieve the maximum benefit.
What are the benefits of exercise in people with type 2 diabetes?
A major benefit of exercise is its effect on the heart and the associated reduction in death from heart disease. In addition to lowering the risk of heart disease in type 2 diabetes, exercise helps to decrease the chances of developing diabetes. This can be especially important for those with pre-diabetes.
In one study, the risk of developing diabetes was reduced by 24% (based on an energy expenditure of 2000 calories per week through exercise). This protective effect of exercise was seen the most in the group at highest risk for developing type 2 diabetes.
The mechanism for this benefit is that exercising muscles are more sensitive to circulating insulin. They thus take up blood sugar more easily and use sugar more effectively. Research has shown that even short term aerobic exercise improves the sensitivity of muscles to insulin.
There is a strong association between diabetes and the location of fat in the body. It has been known for a long time that people with increased internal belly fat (the classic apple-shaped person with a round belly versus the pear-shaped person with a heavier deposit of fat around the hips and thighs) have a higher risk for insulin resistance, high cholesterol, and high blood pressure.
This triad of diseases is part of a disorder called ‘Syndrome X’. Interestingly, in some patients who are not overweight by definition, internal belly fat may still be high, as visualized with special imaging tests of the abdomen.
For example, a classic apple-shaped obese person is a Sumo wrestler. However, Sumo wrestlers are physically active and actually have low internal belly fat stores. Therefore, they are rarely afflicted with blood sugar or cholesterol problems!
In addition to its benefits on muscle insulin sensitivity, aerobic exercise also improves blood cholesterol levels and blood pressure control. This benefit occurs regardless of weight loss. In one study, patients with type 2 diabetes on a 3-month exercise program reduced their triglyceride levels by 20%, increased their good cholesterol (HDL) by 23%, and decreased their blood pressure to better levels too!
The benefits of exercise in patients with diabetes, and in those at high-risk for developing type 2 diabetes (and those with Syndrome X), may include the following:
• Reduced heart disease
• Prevention of diabetes in those at high risk
• Improved muscle sensitivity to insulin
• Better blood sugar control
• Better blood cholesterol profiles
• Better blood pressure control
• Potential weight loss
• Improved general sense of well being
Though exercise is an important part of managing diabetes in general, like everything else it’s not quite black and white. In certain situations, patients with diabetes should approach any exercise regimen with caution.
Additionally, exercise may need to be avoided, at least temporarily, in some patients. And there are a few specific concerns regarding diabetes and exercise that every diabetic trying to maintain a healthy lifestyle should be aware.
Hypoglycemia is a condition that occurs when blood sugars fall to excessively low ranges (usually less than 60mg/dl). With hypoglycemia, patients experience confusion, sweating, shakiness, and in severe cases, coma and seizure.
Note: Exercise can induce hypoglycemia, particularly in patients who are taking insulin, although patients on oral agents are also at risk. In part, this decrease in blood sugar results from an increase in the muscles’ use of glucose and because the liver’s production of glucose is impaired.
Studies have shown that patients taking insulin who reduced the dose of their short-acting insulin by 33-50% before exercising were able to prevent the onset of exercise-related hypoglycemia. While hypoglycemia can occur during or directly after activity, it can also occur 6-12 hours after exercise. Caution is therefore recommended during this period as well.
For patients who exercise regularly and need insulin therapy, an insulin pump is a great option for delivery. The pump provides a constant infusion of insulin that can be adjusted and allows for an extra amount to cover meals. With the aid of a doctor or nurse trained in pump therapy, the dosing can be adjusted to fit exercise regimens.
The only activities for which the pump may not be well suited are swimming and sports involving vigorous movements. These activities can dislodge the cannula, the tube through which the insulin is infused into the body.
Some strategies to avoid hypoglycemia are listed below:
• Measure blood sugars before, during, and after exercise.
• For planned exercise, if you are on insulin, reduce the short-acting insulin by 33 to 50%.
• For unplanned exercise, take 30 to 20g of carbohydrates extra for each 30 minutes of exercise.
• Avoid injecting insulin into the arms and legs and use the abdomen because the insulin will be absorbed more evenly.
• If you exercise in the evening, you may need to add a snack before bedtime to make certain your sugars don’t go too low at night.
Diabetes, Exercise, and Small Blood Vessel Disease
Patients with diabetes often have eye disease, whether they have symptoms or not. The eye disease associated with diabetes results from the formation of small, fragile, easily breakable blood vessels in the retina at the back of the eye. When these vessels break, bleeding in the back of the eye occurs. Continued damage can result in loss of vision.
In patients with extensive eye disease related to diabetes (diabetic retinopathy), the intensity and type of exercise may need to be limited. Activities that should be avoided include excessive straining (as in weightlifting), excessively jarring activities (such as boxing), and exercise that involves severe pressure changes (like diving). If there is early eye disease and no new vessel formation, no limitations are necessary. If kidney disease is present, the only precaution is avoiding exercise that can raise blood pressure.
Diabetes, Exercise, and Large Blood Vessel Disease
Large blood vessels, such as those that normally supply blood and oxygen to the heart, can also be affected by diabetes. A careful medical history and examination are needed in all diabetic patients who have heart disease before they commit to an exercise program. From a recent Consensus Development Conference on the diagnosis of Coronary Heart Disease in people with Diabetes, the American Diabetes Association has published recommendations for exercise stress testing in diabetes patients. Stress testing should be done before embarking on an exercise program.
The recommendations of the American Diabetes Association for testing are listed below:
• Any patient with cardiac symptoms.
• Abnormal resting EKG.
• Peripheral or carotid artery disease.
• Sedentary lifestyle, age > (greater than) 35 years, and plans to begin a vigorous exercise program.
• Two or more of the following risk factors in addition to diabetes:
• Total cholesterol > 240mg/dl, LDL.160mg/dl, or HDL <35mg/dl;
• Blood pressure > 140/90;
• Family history of premature heart disease; and
• Kidney involvement from diabetes.
What does this mean for you?
Before starting on any exercise program, a thorough examination and medical history should be performed by your doctor. Patients who have diabetes should pay particular attention to blood vessel complications.
Another important area to discuss is the estimated calorie expenditure and strategies to lessen the risk of hypoglycemia. Food intake ‒ both before and after exercise ‒ should be reviewed.
Approximately 50% of the calories burned during exercise come from a carbohydrate source (with the remainder coming from fat). You can thus calculate that in a 30 minute exercise session, wherein an activity like cycling at 13 kmph burns about 10 cal/min, a person would need to consume about 38g of carbohydrates (50% of 300kcal =150 kcal or 37.5 g of carbohydrate).
We know this because each gram of carbohydrate is 4 kcal, and 150 divided by 4 is 37.5. These calculations, while a little confusing at first, can be a really valuable tool with some practice and guidance.
Regarding aerobic activity, training sessions should begin slowly. Allow 8 to 12 weeks to reach a desired training level. At a minimum, three to four 20 to 30 min sessions are needed to see a benefit. To estimate your predicted maximal heart rate: take 220 and subtract your age in years. You should be working at about 60 to 70% of this maximum rate to ensure a safe, effective workout.
For example, if you are 40 years old, calculate as follows: 220 – 40 =180 and 70% of 180 = 126. This means your heart rate should be up to 126 beats per minute. It is also important to remember to add a warm up and cool down period to your workout to help prevent injury.
In addition to the above information, the American Diabetes Association has made the following recommendations for exercising:
• Carry an ID card and wear a bracelet that identifies you as having diabetes.
• Be alert for signs of hypoglycemia during and after exercise.
• Drink plenty of fluids before, during, and after exercise.
• Measure blood sugar levels and act if the reading is less than 80mg/dl or greater than 240mg/dl.
If you need more specific information, the American Diabetes Association website is a great resource and the International Diabetic Athletes Association has additional information.
Once again, discuss any question or concerns you may have with your physician before starting any activity program. When done safely, there is no doubt that the benefits of exercise in patients with diabetes far outweigh the risks.