November 14, 2013

What We All Need to Know About Exercise & Diabetes. ~ Salaheddin Sharif & Wendy Keslick

Exercise can be a great tool for empowerment for those with a diabetes diagnosis.

Diabetes mellitus is a group of metabolic diseases characterized by high blood sugar (hyperglycemia) resulting from defects in insulin secretion, insulin resistance or both. It is one of the leading causes of death and disability in the United States, where there are about 24 million diagnosed cases of diabetes with an estimated 6 million additional undiagnosed cases in the general population.

The chronic high blood glucose of diabetes is associated with long-term damage, dysfunction, and failure of various organs, particularly the eyes, kidneys, nerves, heart and blood vessels.

Symptoms of diabetes

Symptoms of marked hyperglycemia can include frequent urination, persistent feeling of being thirsty and hungry, extreme fatigue, blurred vision and cuts and bruises that are slow to heal. In addition, those with type 1 diabetes often experience weight loss, while those with type 2 diabetes might feel numbness, tingling or pain in the hands and feet.

Diagnosis of Diabetes

The diagnostic criteria of diabetes is a fasting plasma glucose ≥126 mg/l. Symptoms of diabetes such as polyuria, polydipsia and unexplained weight loss plus a casual plasma glucose of ≥ 200 mg/dL and two hour plasma glucose more than 200 mg/dL during an oral glucose tolerance test using 75 g of glucose. Currently, diabetes has a new classification system which depends on etiology and pathogenesis rather than modalities of treatment.

Diabetes is divided into four major categories depending on etiology: Type 1, Type 2, gestational and other types. For the purpose of this article we will explore type 2 diabetes.

Type 2 diabetes

Type 2 diabetes accounts for 90-95% of all cases of diabetes. It is insulin resistance with relative insulin deficiency. Previously, it was called non-insulin dependent diabetes, or adult-onset diabetes, or patients who have insulin resistance.

Both genetic and environmental factors have correlation with the cause of type 2 diabetes. Risk factors for the disease include older age, obesity, minority ethnicity, family history, lower socioeconomic status, fat distribution (specifically, intra-abdominal fat distribution) and lifestyle factors that include physical inactivity, overall sedentary life style and a high fat diet. Although there is a strong genetic predisposition for this type of diabetes, the exact genetic defects are not yet well known.

There are various treatment options for type 2 diabetes depending on the patients age, duration of disease and complications.

Generally, the first line of treatment for type 2 diabetes is through diet and physical exercise. The second is drug therapy using oral hypoglycemic agent (Metformin) or insulin injections. Both treatment options have the common goal of maintaining near-normal blood glucose levels and optimal lipid levels, in order to prevent or delay any microvascular, macrovascular and neural complications.

Regular exercise training plays a major role as prevention and control of insulin resistance in pre-diabetes and diabetes. The American College of Sport Medicine (ACSM) recommends a combination of exercise modalities as treatment of diabetes, including endurance training and resistance training for developing and maintaining cardiorespiratory fitness, healthy body composition, muscular strength and endurance.

It is recommended that patients with type 2 diabetes expend approximately 1000 Kcal/week through exercise to achieve weight loss, decrease fat body mass, maintain lean body mass and obtain the other basic exercise-related health benefits. Type 2 diabetes patients can generally meet these goals of improved functional capacity, cardiorespiratory fitness and caloric expenditure by exercising three to four days per week.

The U.S. Surgeon General recommends that physical activity should be performed most, if not all days of the week, to effect favorable health-related benefits such as weight loss, blood pressure reduction and favorable lipid and lipoprotein changes.

Effects of exercise on type 2 diabetes

Diabetic type 2 patients have higher cardiovascular risk factors, including hypertension and dyslipidemia. Therefore, treatment to control glucose levels and reduce long-term complications should focus on plans that include a physically active lifestyle. Essential hypertension (HTN) is a common cardiovascular risk factor occurring in over 60% of type 2 diabetes patients, and it is established that regular exercise training reduces blood pressure in those with hypertension.

The inclusion of nutrition advice, counseling or behavioral intervention helping to reduce fat and body weight can also influence the amount of lipid changes in type 2 diabetes patients participating in physical exercise training. Exercise and diet control are very important for the early treatment type 2 diabetes and to support pharmacological therapy.

The combination of diet control and regular exercise training is more effective than either individually to achieving weight loss and thus improving metabolic control.

Weight loss improves insulin sensitivity and decreases resistance and may be very useful in the early stage of type 2 diabetes when insulin secretion is still sufficient.

Exercise training also leads to preferential mobilization of upper body fat, which is important because visceral adipose tissue is associated with high blood insulin hyperinsulinemia and is negatively associated with insulin sensitivity. Visceral fat is the main source of free fatty acids (FFAs) which oxidize to glucose, leading to high blood glucose level (hyperglycemia).

Exercise training is very effective in long-term weight loss and has constantly been one of the strongest predictors of long term weight control. Therefore, exercise is an important adjunct to diet control in the long-term management of weight. An additional benefit of exercise is that subjects who exercise may stick better to their prescribed diet.

Monitoring of blood glucose during exercise

Self monitoring of blood glucose level is recommended for people with type 2 diabetes who engage in an exercise training physical program, especially during the first few activity sessions. It is advisable for glucose level monitoring to be done before and after an exercise session.

Given the knowledge and understanding of glucose levels, persons with type 2 diabetes, in consultation with their physician and health care professional, can take appropriate action by reducing medications before exercise or increasing carbohydrate consumption before or after exercise to reduce the likelihood of hypoglycemia. Adjustment to medications is preferable over increasing caloric intake to prevent hypoglycemia in those trying to reduce body weight.

Effects of exercise on blood glucose levels

It is important for type 2 diabetes patients to exercise regularly to decrease blood glucose levels, because the acute effect of one exercise session on blood glucose level lasts less than 72 hours. Patients with type 2 diabetes who are taking insulin should exercise every day to decrease the difficulty of balancing caloric needs with insulin dosage.

Resistance strength exercise leads to increase muscle mass and hypertrophy, which increase muscle glucose uptake, whereas aerobic exercise improves insulin sensitivity and glucose uptake. Both aerobic and resistance exercise improve insulin action, blood glucose levels, and fat storage and oxidation in muscle tissues

Cardiovascular Training

ACSM recommends that the total time of the physical activity session be at least 30 minutes to achieve the desired energy expenditure. If necessary, this goal can be reached by dividing the exercise training into three 10 minute sessions, whereby 30 minute of exercise training is accumulated in a single day to ensure the needed energy expenditure. As the patients increase their level of fitness, the duration workout should be increased gradually to approximately 60 minutes.

The best types of exercise training for type 2 diabetes patients are those that give more control over intensity, have less variation in energy expenditure, are easily maintained and require little skill. Personal interests and goals should also be considered, as these factors are important in motivating the patients with type 2 diabetes to start and maintain their exercise program.

One benefit of maintaining low to moderate exercise training activities is that it helps to minimize the risks of injury and maximizes the health benefits in those patients. Also, the lower intensity activity affords easy level of exertion and enhances adherence to exercise training programs. In addition, it decreases musculoskeletal injury and foot trauma, mainly when weight-bearing activity is recommended.

Monitoring the intensity of exercise in patients can be done through measuring heart rates or the ratings of perceived exertion (RPE). The duration of exercise training is directly associated with the caloric expenditure requirements and inversely associated with the intensity.

It is important to choose types of exercise training that can safely and efficiently maximize caloric expenditure. Walking is the most commonly and most convenient type of exercise training for diabetes patients. However, stationary cycling, aquatic activities and other alternates are viable and safe choices for those patients with diabetes complications (peripheral neuropathy) who need types of exercise other than weight bearing activities.

Resistance Training

Resistance training has the potential to improve muscular strength, muscular endurance, flexibility and body composition while decreasing risk factors for cardiovascular disease. In addition, resistance training also improves glucose tolerance and insulin sensitivity. Type 2 diabetes patients should participate in resistance training at least two days per week, combining 8-10 exercises that involve the major muscle groups. Each particular exercise should be done for a minimum of one set of 10–15 repetitions to near fatigue, with slow progression.


Yoga has been shown to be effective in the treatment diabetes. The asanas (yoga postures) and breath work have been shown to help control blood glucose levels, improve overall circulation, provide therapeutic effects to the organs and the glands, strengthen and improve the functioning of the pancreas. In addition, a study published in the Nepal Medical College Journal showed that yoga can decrease the waist-hip ratio, indicating its effectiveness in the redistribution of fat.

Developing a fitness protocol

When first embarking on a fitness program, it is recommended that people with type II diabetes engage in physical activity at a comfortable level (RPE 10–12) for about 10–15 minutes at a very low intensity at least three times per week and preferably five times per week.

The duration of exercise training should be gradually increased to accommodate the functional capacity and clinical status of the patients. Given that older age and obesity are common factors associated with type 2 diabetes, a longer period of time may be necessary for the older and/or obese person to adapt to a recommended physical activity program.

After the desired duration of activity is achieved, any increase in intensity should be small and approached with caution to minimize the risk of undue fatigue, musculoskeletal injuries, and relapse.

Initially, progression in exercise training should be in frequency and duration rather than intensity, as this offers a safe activity level that can be performed without undue effort and increases the likelihood of sustaining the activity habits.

Beyond the physical effects of exercise, there is also an improvement in overall mood and self-esteem.

There are physiological and psychological benefits of regular exercise for those with type 2 diabetes, including decreased stress response to psychosocial stimuli, decreased sympathetic nervous system activation to cognitive stress, reductions in depression, heightened self-esteem and reduced emotional perturbations associated with life’s stressful events. Regular physical activity can play a role in reducing this stress, enhancing psychological well-being and improving the quality of life for type 2 diabetes patients.

This is extremely important because of the effect of diabetes on lifestyle and health. For example, the psychosocial adjustments to diabetes required by those with type 2 diabetes in later life often have important consequences on perceived stress, glucose control and psychological health. The benefits of exercise are of importance relative to augmenting perceived health and sense of self, and lessening the negative impact of stress and depression on disease management. In addition, treatment for those with type 2 diabetes should include social or family support systems that help in increasing adherence to treatment plan.


All patients with type 2 diabetes should be screened before beginning any type of training and receive proper supervision and monitoring. The progressive increase in exercise training for type 2 diabetes patients is specific for every patient and dependent upon many factors including age, functional capacity, medical and clinical status, and personal preferences and goals.

Published by permission from WendyKeslick.com

References for article

Salaheddin Sharif, MD, MS, RCEP, is a sport medicine physician and registered clinical exercise physiologist at ACSM. He is a lecturer at Physiology Department, School of Medicine, Benghazi University in Libya, where he teaches theory and practical classes for medical, as well as dental, pharmacy and public health students within the university and various affiliated centers. He includes sports as essential part of his life and has earned a Black Belt of International Karate Organization Kyokushin Kaikan – I.K.O. Matsushima. He is determined to obtain his PhD in the United States. He also founded a nonprofit called Libyan American Friendship Association.

Wendy Keslick is a massage therapist, yoga instructor, writer and humanitarian. She is passionate about being part of the conversation of our evolving humanity.  Borderline obsessions include organic and natural living, vegetarianism and veganism, social justice issues, documentaries and current events.  She is determined to learn Arabic in this lifetime. Her daughter, international travel, exploring other cultures and green smoothies are her passions.

She also founded a nonprofit called Galen International Health (formerly Children Creating Bridges). Volunteering for this organization has taken her to Syria to be part of three medical delegations to help with the Iraqi refugee crisis.  Follow her on Facebook and Twitter.

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Editor: Bryonie Wise


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