Exercise/diabetes

Recommending Exercise for Patients With Diabetes:

Diabetes mellitus affects an estimated 150 million people worldwide, including 16 million Americans; according to estimates, by the year 2025, the number of patients suffering from the condition will exceed 300 million.

Type 1 diabetes, which afflicts 10% of sufferers, is characterized by insulinopenia, requiring that patients take insulin for survival.
This overview of type I diabetes provides the clinician with an introduction to its etiology and how it is diagnosed, then explores the influence of exercise on patients with the condition, including the many general effects of a consistent exercise regimen:

* improving glucose tolerance by augmenting insulin sensitivity;
* decreasing muscle capillary basement membrane thickening and arterial pulse volume recordings;
* increasing lean body mass and work capacity;
* improving overall weight management;
* reducing serum total cholesterol, low-density lipoprotein (LDL) and very low-density lipoprotein levels (VLDL), while raising high-density lipoprotein (LDL) levels; and
* increasing cardiac function.

Numerous management strategies and guidelines for exercise are included and can be obtained from the Internet, along with steps clinicians should take in evaluating patients with type I diabetes (prior to recommending any exercise regimen); specific considerations in terms of diet, exercise intensity and duration, and energy requirements; and potential risks and complications.

The authors emphasize that caring for diabetes patients requires that all clinicians be responsible for education about blood glucose self-monitoring; proper exercise prescription; appropriate dietary and insulin management plans; pre-participation clearance; and ongoing education. With respect to exercise, they note: "Exercise has risks and benefits that must be understood so that participation yields a safe, enjoyable outcome. ..."

Recommending Exercise for Hypertensive Patients

Hypertension, defined as blood pressure (BP) of 140/90 mm Hg or greater, affects approximately 50 million Americans. Mild-to-moderate increases in BP can dramatically amplify risk for stroke, renal disease, and left ventricular hypertrophy; extreme elevations in BP can raise risk for these conditions even more.

Nonpharmacologic interventions, such as exercise programs, can serve as comprehensive therapy for some patients and adjunctive therapy for others.

All current hypertension treatment guidelines recommend exercise as an adjunctive therapy for mild hypertension, although drug treatment is recommended in addition to exercise in severe cases. Exercise reduces BP; low-density lipoprotein (LDL) cholesterol levels; insulin resistance/ glucose intolerance; and body weight. This paper states that aerobic exercise and diet-induced weight loss are the most effective and physiologically desirable means to achieve a decrease in atherosclerosis, which leads to coronary artery disease.

Since the authors propose that all patients with controlled hypertension should participate in exercise, this review offers tips on how to prescribe exercise to patients of various ages, weights, and hypertension levels. Some of the key points of the review:

* Patients should have a thorough physical and cardiac evaluation before beginning an exercise program.
* Extreme hypertension patients (BP of 180/105 mm Hg or more) should only begin exercise training after medication controls their BP.
* Sudden cardiac death is the most dangerous complication related to exercise therapy in hypertension patients, but the risk is "very minimal."
* Graded exercise stress tests (GXTs) are useful for measuring the magnitude of BP response to exercise, rate of recovery, and arrhythmias.
* Aerobic exercises, including walking and running, are the preferred endurance exercises for hypertension patients. Swimming is a good alternative for obese, injured, asthmatic, or otherwise impaired individuals. Tai chi chuan has been shown to safely reduce BP, but no large, randomized trials have validated its effects.
* Vigorous, rhythmic exercises - such as sprinting, rowing, and downhill skiing - should be discouraged in hypertensive patients. High-altitude sports in general should be discouraged because of additional risk for elevated BP from cold and reduced air pressure.
* Low-to-moderate exercise training intensity may be more effective than intense regimens for hypertensive patients; heart rate should fall within 50-70% of predicted maximum during exercise. Regimens will likely take one to three months to significantly reduce BP, but must be maintained thereafter for indefinite results.

Note: This paper is excellent for clinicians seeking to incorporate more active health promotion strategies for their patients. Available for free on the Internet at the address below; several links to helpful articles and exercise tables also are provided.

Chintanadilok J, Lowenthal DT. Exercise in treating hypertension: Tailoring therapies for active patients. The Physician and Sportsmedicine 2002:30(3). Available free atwww.physsportsmed.com.

 Recommending Exercise May Benefit Patients with Knee Osteoarthritis

Reducing pain and disability are the predominant goals of exercise therapy for patients with osteoarthritis (OA). Exercise programs in this regard focus on improving muscle strength, joint stability, range of motion and aerobic fitness, and making corrections of the walking pattern when necessary.

The authors of this study note that previous treatment guidelines and published studies on exercise therapy for OA fail to "satisfy the current methodologic requirements for literature reviews." The authors addressed this perceived shortcoming by including recently published randomized, controlled clinical trials and by applying updated review methodologies to their analysis.

A comprehensive literature search of the Medline (Jan. 1966 to Sept. 1997), Embase (Jan. 1988 to Sept. 1997), Cinahl (Jan. 1982 to Sept. 1997) and the Cochrane Controlled Trial Register databases revealed 11 trials, six of which met at least 50% of the authors� validity criteria: randomized studies of treatment of OA of the hip or knee in which exercise therapy was utilized in one or more treatments.

Analysis of the available literature showed beneficial short-term effects from exercise therapy in patients with OA of the knee, but less so in OA of the hip. These benefits were small to moderate when assessing self-reported disability, including observed disability in walking, and moderate to great in terms of patient's global assessment of the effect of exercise. The authors caution that the small number of quality studies "restricts drawing firm conclusions," and call for further research to support their recommendation.

Van Baar ME, Assendelft WJJ, Dekker J, et al. Effectiveness of exercise therapy in patients with osteoarthritis of the knee. Arthritis & Rheumatism, July 1999:42(7), pp1361-69.

Recommending Exercise

Lifelong Exercise Might Prevent Heart Failure in Aging Hearts

Heart failure associated with aging generally occurs when there is a stiffening of the heart muscle, which causes pressure that in turn resists blood flow into the heart. As a result, the heart�s main pumping chamber, the left ventricle, cannot pump blood throughout the body in a normal capacity; this can eventually lead to complete diastolic heart failure.

Researchers from the University of Texas Southwestern Medical Center in Dallas compared the function of the left ventricle in 12 healthy but sedentary senior citizens, 12 senior Masters athletes, and 12 young, sedentary adults (average age 29) to determine if aging was the primary cause of left ventricle failure, or if physical inactivity was also partly to blame.

Results: Researchers found that sedentary hearts were stiffer than those of the Masters athletes; moreover, the function of the athletes' hearts was virtually the same as that of the younger study participants - something that came as a surprise to the researchers. "We found that older, sedentary individuals' hearts were 50 percent stiffer than the Masters athletes, which we expected," said researcher Benjamin Levin, MD, professor of internal medicine at the university. "What we didn't expect was that the hearts of these senior athletes were indistinguishable from those of the healthy younger participants."

"A sedentary lifestyle during healthy aging is associated with decreased left ventricle compliance, leading to diminished diastolic performance. Prolonged, sustained endurance training preserves ventricular compliance with aging and may help to prevent heart failure in the elderly," the researchers concluded.

Zadeh AA, Dijk E, Prasad A, et al. Effect of aging and physical activity on left ventricle compliance. Circulation, 2004; 110:1799-1805.

Exercise Lessens Prostate Trouble?

Most older men suffer lower urinary tract symptoms resulting from prostatic enlargement caused by benign prostatic hyperplasia (BPH).

Because sympathetic nervous system activity, which is decreased by physical activity, is associated with increased smooth-muscle tone and prostatic symptoms, the researchers conducting this study assessed whether exercise leads to a reduction in lower urinary tract symptoms.

The subjects were nearly 4,000 men 40 to 75 who were free of diagnosed cancer, including prostate cancer both at baseline (1986) and during follow-up.

The subjects were observed for incidence of

surgery for BPH between 1986 and 1994, during which time more than half the subjects did undergo BPH surgery.

The results of the study showed that physical activity was inversely related to total BPH risk. Men who walked two to three hours per week had a 25 percent lower risk of total BPH and the lower urinary tract symptoms associated with BPH.

Chiropractors who advise their patients regarding exercise and nutrition may wish to suggest that, based on the results of this study, exercise is a safe and easy method for decreasing the frequency of lower urinary tract symptoms.

Platz EA, Kawachi I, Rimm EB, et al. Physical activity and benign prostatic hyperplasia. Archives of Internal Medicine, Nov. 23, 1998;158(21), pp2349-56.

[See also the summary of the Wilt et al. study of Saw Palmetto for Benign Prostatic Hyperplasia, on page 7 of this issue of CRR.]

Exercise: Optimal Options for Heart Patients

Regular physical activity under a doctor's direction is a key element of heart patients' efforts to manage their disease. Individuals who have had heart attacks, balloon angioplasty or bypass surgery, or who are affected by heart disease in other ways, must take many steps to improve their health.

Exercise, in addition to the other changes they make in the behavior and nutrition, can make them more confident, less depressed and less stressed. It can even lower their risk of dying and improve their overall sense of well-being.

This article recommends an optimal program of aerobic exercise of at least 30 minutes three times a week. It is written to and for patients and carefully explains how they can gradually build to higher levels of activity and tells them how to monitor the impact of their exercise. It also outlines how strength and flexibility exercises can contribute to improved heart health. Throughout, it provides guidelines and discusses cardiac warning signs that can indicate that the patient is overdoing it. The article includes a "Complete Heart-Care Package" of healthy steps patients can take to reduce their risk of further heart problems.

Note: Doctors of chiropractic will find the information in this article of use to them and their patients with heart problems. It is an easy-to-follow regimen in the spirit of the practical approach to wellness, prevention and rehabilitation. This is an excellent lay person's 2-page handout.

Exercise Reduces Stroke Risk?

It is plausible, physiologically, for physical activity to decrease stroke risk. However, epidemiological studies have produced mixed findings. Furthermore, few studies have examined specific kinds and intensities of activities.

The purpose of this study was to examine the association between walking, climbing stairs, participation in sports and recreational activities and stroke risk.

The purpose of this study was to examine the association between walking, climbing stairs, participation in sports and recreational activities and stroke risk.

This study of 11,130 men was drawn from individuals tracked in the Harvard Alumni Health Study, an ongoing study of the predictors of chronic diseases among men matriculating as undergraduates at Harvard University between 1910 and 1950. 

The current study included men 43 to 88, with a mean age of 58 who were free of cardiovascular disease or cancer.

Physical activity was found to be associated with decreased risk of stroke in men, including older men. With levels of energy expenditure up to 3000 kcal/wk, risk declined steadily. Beyond this, the association weakened. The data indicated that walking ≤ 20km/wk was associated with significantly lower risk, independent of any other physical activity components. Climbing stairs and activities of at least moderate intensity were related to lower risk. But light-intensity activities were unrelated to stroke risk. Furthermore, men who participated in recreational activities experienced lower stroke rates than those who only walked or climbed stairs but did not engage in recreational activities. 

Recommend Exercise to Fight Osteoarthritis

Arthritis is the most common disability in the United states, and osteoarthritis the most common form of arthritis, affecting an estimated 33% of the population age 60 and older. Declines in muscle strength, aerobic fitness and functional capacity may be important risk factors in the acceleration of the disease process.

A sensible, moderate exercise program can indirectly protect osteoarthritic joints in a number of ways:

* Stretching and range-of-motion exercises can improve mobility and reduce joint fatigue and mechanical stress.

* Resistance training can strengthen muscle around the affected joints, which improves shock absorption, stabilizes the joints, and reduces stresses that tend to accelerate cartilage degeneration.

* Any exercises promoting healthy weight loss will also reduce stress on weight-bearing joints (especially the knees).

Included is a discussion of potential exercise variations/methods which may be most appropriate for combating the effects of osteoarthritis. Many patients can achieve substantial benefits from a well-designed, sensible exercise regimen. Chiropractors can play a key role by educating patients on the value of exercise in pain management and providing training suggestions and encouragement.

Exercise Each Day Keeps Gallstones Away

Gallstone formation has been linked to blood-sugar intolerance and excess insulin levels. A study of 45,813 men (aged 40 to 75) assessed physical activity; incidence of gallstone disease; dietary, alcohol and smoking habits; medication use; and occurrence of diagnosed medical conditions other than gallstone disease, over an eight-year period.

Vigorous physical activity showed a distinct inverse relationship with the risk of gallstone disease. After adjustment for possible confounding factors, each increase in physical activity of 25 metabolic equivalents (METs) per week was associated with a distinct reduction in risk. One MET was defined as the energy expended by sitting quietly, equivalent to an oxygen uptake of 3.5 ml/kg of body weight per minute. Activities that required six or more METs per hour were classified as vigorous; those that required less than six METs per hour were considered nonvigorous.

Conclusions: Physical activity, especially rapid walking, jogging or hiking, may decrease risk for symptomatic gallstone disease by improving blood-sugar utilization. The overall level of activity, rather than the particular form of exercise, may be the main determinant of risk. 

Moderate-Intensity Exercise Reduces Diabetes Risk

Vigorous exercise is known to improve insulin sensitivity, and is also associated with a lower risk of non-insulin-dependent diabetes mellitus. A survey of Caucasian, African American and Hispanic men and women (aged 40 to 69) found that energy expended by both vigorous and nonvigorous exercise (i.e., brisk walking) was associated with significantly higher levels of insulin sensitivity.

In 1,467 subjects with glucose tolerance ranging from normal to mild non-insulin-dependent diabetes, an intravenous glucose tolerance test assessed insulin sensitivity.

Mean insulin-sensitivity levels showed a positive improvement from both vigorous and nonvigorous physical activity after adjustments for potential mediators, body-mass index, and waist-to-hips ratio. Results were similar for subgroups of sex, ethnicity and diabetes. These findings lend further support to current public health recommendations for increased nonvigorous exercise (i.e., 30 minutes per day of moderate-intensity physical activity) which may decrease the risk of diabetes. 

Regular Exercise Shows Benefits -- Even After Sedentary Lifestyle

The benefits of exercise have been well-documented over the years. Numerous studies have shown that exercise can help reduce incidences of disease, promote weight loss, and improve mental health.

A recent study set out to examine if exercise during the senior years has benefits in people who were previously sedentary.

Canadian researchers investigated two groups of previously sedentary healthy adults, ages 55-75 years at baseline. One group remained sedentary during the study, while the other group initiated and engaged in regular exercise consisting of 30- to 45-minute aerobic sessions, three times a week, for a minimum of 46 weeks a year over the 10-year study period. Investigators evaluated the participants for fitness levels, metabolic risk factors for cardiovascular disease, and comorbid conditions.

At the conclusion of the study, researchers examined data for 161 participants in the active group and 136 participants in the sedentary group. According to the study, "The active group showed a significantly lower prevalence (11%) of the metabolic syndrome than the sedentary group (28%) at 10 years." The sedentary group also had a 13% decrease in fitness over the 10-year study period, while the exercise group showed a small increase in fitness levels. HDL, or "good" cholesterol, showed a 9% increase in the exercise group, compared to the sedentary group that showed an 18% decrease in HDL. The active group also had "fewer comorbid conditions, and fewer signs and symptoms of cardiovascular disease," than their sedentary counterparts.