The study discussed here considers how that technology can help give type 1 diabetics the freedom that non-diabetics take for granted.

Exercise poses unique risks for people with type 1 diabetes.

Blood Sugar Complications

In type 1 diabetes, the patient’s pancreas produces little or no insulin. Without a natural supply of the hormone responsible for mediating blood sugar concentrations, a type 1 diabetic depends on regular insulin injections instead.

“Diabetes management involves carefully balancing insulin injections and carbohydrate consumption to maintain a blood sugar level in between these two extremes.”

Excessive blood sugar increases the risk of diabetic complications, including retinal and peripheral nerve damage, which can lead to blindness and the loss of digits, respectively. Low blood sugar is equally dangerous, potentially causing dizziness, confusion, and unconsciousness. Diabetes management involves carefully balancing insulin injections and carbohydrate consumption to maintain a blood sugar level in between these two extremes.

Exercise and Glucose

Exercise can play an important role in maintaining this balance. It burns glucose and improves insulin sensitivity. Moreover, diabetics derive the same exercise-related improvements in mental wellbeing and cardiovascular health that non-diabetics do.

Unfortunately, exercise also poses unique risks for diabetics. The glucose burned during exercise may not be replenished quickly enough, leading to hypoglycemia and its associated risks. The longer the exercise duration, the greater the risk.

“[A]ny adjustment to a diabetic’s insulin regime requires advance planning. For this reason, fear of hypoglycemia is a significant barrier to exercise among type 1 diabetics.”

While, in theory, it is possible to increase carbohydrate consumption or reduce insulin levels to compensate, doing so runs into practical challenges. There is no scientific consensus on exactly what adjustments are recommended, with estimates ranging from an additional thirty grams of carbohydrate per hour to almost double that amount.

Moreover, any adjustment to a diabetic’s insulin regime requires advance planning. For this reason, fear of hypoglycemia is a significant barrier to exercise among type 1 diabetics. It can be especially problematic when considering spontaneous activities: a hike in the woods or a bike ride with family members, for example.

Any adjustment to a diabetic’s insulin regime requires advance planning.

The ECRES Solution

The ECRES algorithm (Exercise Carbohydrates Requirement Estimating Software) seeks to remedy this problem. Given the patient’s normal diet, insulin regimen, and activity level, it estimates the insulin profile and required carbohydrate intake over the course of a day. When exercise is contemplated, the algorithm can estimate carbohydrate requirements based on the expected exercise intensity and duration, given the patient’s measured blood sugar level at the time. Thus, it allows patients to determine how to adjust their carbohydrate intake to accommodate spontaneous activity.

“The ECRES algorithm seeks to remedy this problem. Given the patient’s normal diet, insulin regimen, and activity level, it estimates the insulin profile and required carbohydrate intake over the course of a day.”

Because it depends only on information readily available to the patient – blood sugar level, insulin and carbohydrate intake, and estimated heart rate – ECRES is suitable for implementation by smartphones, fitness monitors, and other portable electronic devices and can be readily incorporated into the patient’s daily life.

What the Research Says

Previous research has validated the ECRES algorithm for short-duration exercise of an hour or less. In the study discussed here, researchers at the University of Udine, Italy applied it to long-duration, low- to moderate-intensity exercise.¹

Nine participants – five male and four female – walked on a treadmill for three hours at a “brisk” pace, estimated at 50-60% of maximum heart rate. Heart rate was monitored continuously and blood sugar at thirty-minute intervals. The participants, all of them type 1 diabetics with well-established metabolic control regimes, were given either candy or direct glucose injections as needed to maintain blood sugar at a safe level. Participants followed their normal diet and insulin regimens before the test, simulating spontaneous activity under “free living” conditions.

After the test, actual glucose consumption was compared to the glucose requirement predicted by the ECRES algorithm. The two were found to be in close agreement. Moreover, the ECRES estimate was closer to the actual requirement than other methods found in the literature. The thirty grams of carbohydrate per hour estimate would have led to excessive blood sugar levels, so higher intakes would have been even worse.

The ECRES algorithm can help predict carbohydrate intake that will maintain blood sugar in a healthy range.

Conclusion

While the researchers conceded that the small sample size and precise exercise protocol limited the applicability of their work, they concluded that the ECRES algorithm can remove a major barrier to exercise among type 1 diabetics. Rather than evaluating the metabolic consequences of exercise for themselves, they can depend on the algorithm to suggest carbohydrate intake that will maintain their blood sugar in a healthy range.

Further Reading:

• Working With Special Populations, Part 3: Diabetes Mellitus
• Weight Training Can Help Diabetics Manage Blood Sugar
• Prevent Type 2 Diabetics With Resistance Exercise
• New on Breaking Muscle Today

References:
1. Maria Pia Francescato, et. al. (2015) “Prolonged Exercise in Type 1 Diabetes: Performance of a Customizable Algorithm to Estimate the Carbohydrate Supplements to Minimize Glycemic Imbalances.” PLoS ONE 10(4): e0125220. doi:10.1371/journal.pone.0125220

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Background

Since carbohydrates are important for energy production in each cell, the energy levels experienced by people with metabolic disorders that impact glucose levels, such as diabetes, tend to be quite low. For athletes, this might negatively impact strength.

Insulin is also an anabolic hormone, meaning it promotes muscle growth. If an athlete’s response to insulin is abnormal, their ability to develop muscle could be reduced. This would make for a double whammy when it comes to strength. Both reduced energy and reduced muscle mass are performance killers.

Since those with a family history of diabetes are at risk for developing metabolic disorders, the researchers wondered if higher-risk individuals might also respond differently to exercise.

Study Design

38 healthy men and women participated in this study. Eighteen of them had a family history of diabetes, while the remaining twenty did not.

They engaged in a resistance exercise program five days per week for seven weeks. The program included full body resistance circuits, core training, and plyometrics. The resistance and core workouts were brief, lasting ten to fifteen minutes, with the plyometric workout lasting forty minutes. Strength, body mass index (BMI), resting heart rate, and other markers were measured before and after the program.

The researchers estimated the function of insulin in the body by measuring the fasting blood glucose, a standard metabolic disorder test. High blood glucose would indicate a malfunction in insulin sensitivity, meaning that glucose could get into the cells. Since exercise increases the demand of glucose in the muscles, a well-functioning insulin system will yield a healthy drop in blood sugar post-exercise. The researchers thought those participants with a family history of diabetes would demonstrate a reduced drop in blood sugar.

Results

Fasting glucose was affected similarly between the two groups, regardless of the family history of diabetes. This is great news for people concerned about metabolic disorders impacting their strength and energy levels, as it means insulin production was able to respond appropriately to the workout.

Furthermore, there was also an inverse relationship between fasting glucose after exercise and strength improvement over the course of the seven-week program. As postulated above, this indicates that a robust and well-functioning metabolic system is good for athletic advancement. The results also suggest that a person with a history of diabetes in their family but no present metabolic disorder will not be limited by their genetics.

If you have a family history of diabetes, you will be at greater risk for impaired metabolic function. However, it seems that this history alone is not as great a stimulus to the body as exercise is. Exercise regularly and maintain healthy eating habits and a good bodyweight to mitigate the risk.

References:

1. Ryan D. Russell, et. al., “Short bouts of high-intensity resistance-style training produce similar reductions in fasting blood glucose of diabetic offspring and controls,” Journal of Strength and Conditioning Research, DOI: 10.1519/JSC.0000000000000624

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The post Strength Training and Diabetes: Do Genes Make a Difference? appeared first on Breaking Muscle.

Researchers examined data from a long-term study of nurses in the United States. The study followed almost 100,000 female nurses for eight years. The women recorded their daily activities in great detail, including any exercise they did. The results show that any type of resistance exercise decreased the likelihood of developing diabetes.

The researchers defined resistance exercise very loosely. The way this study was conducted, any type of muscle-strengthening routine that wasn’t aerobic exercise was counted as resistance exercise. That means yoga, pilates, bodybuilding, strength training, weightlifting, and CrossFit were all classified under the same category. That’s great news, because it means the resistance exercise necessary to prevent diabetes can come from almost any activity.

Before you get out the pitchforks, remember that we’re talking about exercise as a goal to prevent disease. Nobody is saying that all those activities will achieve the same physical results. But it appears they could all be equally effective in simply preventing diabetes.

The study also revealed that more resistance exercise resulted in less risk of diabetes, but the big drop in risk came after just 1.5 hours per week. So a person who performs weight training for seven hours per week is more protected than someone training for only 1.5 hours per week, but not by much. The person who exercises just for disease prevention gets much more bang for her buck from about ninety minutes of resistance training.

The study also showed that the ultimate protection came from both aerobic exercise and resistance training combined. So programs that involve both types of training might be most effective. Interestingly, the most risk reduction from aerobic exercise alone came after 2.5 hours per week.

So what do we learn from this study? First, resistance training in any form helps prevent diabetes. Second, the best protection comes from combining resistance training with aerobic exercise. So when someone asks you about the best way to exercise for general health, don’t make them believe there is only one way that works, to the exclusion of all others. This study shows that general health and disease prevention can be achieved with a variety of different programs. The best program appears to be the one that will stick.

References

1. Anders Grontved, et al. Muscle-Strengthening and Conditioning Activities and Risk of Type 2 Diabetes: A Prospective Study in Two Cohorts of US Women. PLOS Medicine. Published: January 14, 2014. DOI: 10.1371/journal.pmed.1001587

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Pathophysiology of Type 1 Diabetes Mellitus

Those with type 1 diabetes have an absolute deficiency of insulin cause by marked reduction in insulin-secreting beta cells of the pancreas. Insulin from an outside source must be supplied via injection or an insulin pump. Those with type 1 diabetes are prone to developing ketoacidosis (high levels of ketones) when low insulin levels result in hyperglycemia.

The cause of type 1 diabetes is thought to involve an autoimmune response in genetically susceptible individuals that affects the beta cells that leads to their destruction. The nature of the genetic influence in the pathogenesis of type 1 diabetes is unclear, but the human lymphocyte antigen types DR3 and DR4 are associated with an increased risk for type 1 diabetes.

It’s important to note that this type of diabetes usually appears before the age of thirty, but it can occur at any age. Of the 20.8 million people with diabetes in the United States only 5-10% have type 1 diabetes.

Pathophysiology of Type 2 Diabetes Mellitus

Those with type 2 diabetes are considered to have a relative insulin deficiency, because they can have elevated, reduced, or normal insulin levels. People with type 2 diabetes present with hyperglycemia regardless of their insulin status.

The pathophysiology of type 2 diabetes is still relatively unclear, but contributing factors include genetics, environment, insulin abnormalities, increased glucose production in the liver, increased fat breakdown, and defective hormonal secretions in the intestine. In type 2 diabetes, peripheral tissue insulin resistance and defective insulin secretion are common features. With insulin resistance, glucose does not readily enter the insulin sensitive tissues (think muscle and adipose tissue) and blood glucose rises. When blood glucose rises, the beta cells of the pancreas being to secrete more insulin to try to maintain normal blood glucose concentrations. Unfortunately, this is usually not effective for lowering blood glucose and may further contribute to insulin resistance.

The mechanisms underlying insulin resistance also remain unclear, although they likely involve defects in the binding of insulin to its receptor and postreceptor events, such as glucose transport. Since the majority of people with type 2 diabetes are overweight or obese at the time of onset, obesity is considered a significant contributor to insulin resistance. Most people with type 2 diabetes have lost the first or acute phase of insulin release. Insulin therapy may or may not be required, depending on the degree of functional insulin, or insulin sensitive or responsiveness (or both), remaining. Those with type 2 diabetes do not develop ketoacidosis unless under conditions of unusual stress, such as some sort of trauma.

Of the 20.6 million people diagnosed with diabetes, 90-95% are diagnosed with type 2 diabetes.

Coach’s Corner: Working with Type 1 Diabetes

Type 1 diabetes care will differ from someone with type 2 diabetes. It’s not that someone with type 1 diabetes can’t exercise, but there are specific things to look out for when working with them and the severity of the disease will differ by person (especially if someone has an insulin pump). Some information from the Canadian Journal of Diabetes is that moderate-intensity aerobic exercise increases the risk of hypoglycemia because of more rapid circulation.

Exercise enhances the absorption of exogenous insulin, so it’s important that a doctor be involved with any exercise for a type 1 diabetes patient. Since type 1 diabetes patients are on insulin therapy, either by syringe or an insulin pump, adjustments in dosage, careful blood glucose monitoring, and attention to diet at the time of exercise are needed to prevent hypoglycemia. For these reasons, a doctor should be well aware of what types of exercise the patient is doing in case any adjustments need to be made. In some cases, patients on pump therapy may need to decrease bolus doses by 20-50%, and may choose to discontinue basal insulin during exercise.

In regards to brief high-intensity or anaerobic activity, it can cause post-exercise hyperglycemia. For this reason, some patients may decrease their basal insulin by 25% after exercise. Now, I can’t stress this enough: you should not make these adjustments unless you are the physician to the afflicted individual. You must keep in contact with the patient’s physician for them to make these insulin changes. These numbers are simply here to give the exercise professional an idea of insulin fluctuations.

According to the Canadian Journal of Diabetes, small amounts of anaerobic activity in the form of sprints or basic resistance exercises during aerobic exercise sessions may decrease the drop in blood glucose levels associated with moderate-intensity aerobic exercise. But it’s important to mention these theories are still being tested, so as a trainer, always err on the side of caution.

Practical exercise programs should be given for those with type 1 diabetes, but there are a lot of risks in working with those with type 1 diabetes and the priority should always be keeping them safe. It’s best for exercise professionals to work alongside the patient’s physician so you do not cause any extraneous stress or ketoacidosis (which can be potentially fatal). There are many professionals who work with patients with well-controlled type 1 diabetes who wish to exercise for a better quality of life.

Exercise and Type 2 Diabetes

It’s important for exercise professionals to understand that diet and exercise go hand in hand for those with type 2 diabetes. A six-year clinical trial evaluated the effects of diet and exercise lifestyle interventions on the occurrence of type 2 diabetes in individuals with impaired glucose tolerance. In the study, 577 men and women were assigned to one of four groups: control, diet only, exercise only, or both diet and exercise. It was proven that exercise combined with diet decreased the incidence of diabetes after the six-year intervention.

Now, you may be wondering about the effectiveness of resistance training versus aerobic training, in that now we have many forms of exercise, be they CrossFit, endurance, powerlifting, or yoga. The Journal of Sports Medicine did a study on resistance training versus aerobic training. In the study, both aerobic exercises and resistance exercise were recommended treatments for those with type 2 diabetes, but researchers wanted to find the optimum type of exercise for those with the disease.

The study used a randomized control group with people with type 2 diabetes, with an age range of eighteen years or older. The duration of the trial was eight weeks with a predetermined frequency, intensity, and duration of the exercise. The conclusion of the study found that even though there were some physical fitness differences between the aerobic and resistance groups, the differences were of no clinical importance. So there is really no evidence that resistance training greatly differs from aerobic exercise in regards to the impact on cardiovascular risks or safety.

The important part of this study concluded that for type 2 diabetic patients using one or the other training method is less important than doing some form of physical activity. It’s important that whatever exercise program someone with type 2 diabetes chooses, it will be the one that is right for them. For exercise professionals, it’s important for you to understand how to modify movements for type 2 diabetes patients new to exercise and how to make the best nutrition plan for them in order to improve their quality of life.

References:

1. Hornsby Guyton W and Albright, Ann L., “ACSM’s Exercise Management for Persons With Chronic Diseases and Disabilities” (Illinois: Human Kinetics, 2009), Kindle Edition, Chapter 24.

2. Katch, Frank I, Katch Victor L, and McArdle William D., “Exercise Physiology: Energy, Nutrition, and Human Performance“ (Baltimore: Lippincott Williams and Wilkins, 2007), 452-53.

3. Yardley, Jane E, et. al., “Resistance Exercise in Type 1 Diabetes.” Canadian Journal of Diabetes 37 (2013): 420-26, accessed December 18, 2013, doi:10.1016/j.jcjd.2013.07.020.

4. Yang, Z. et al. “Resistance Exercise Versus Aerobic Exercise for Type 2 Diabetes: A Systematic Review and Meta-Analysis.” Journal of Sports Medicine (2013): ePub, accessed December 18, 2013, doi: 10.1007/s40279-013-0128-8.

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