Aerobic exercise has long been considered the "power house" when it comes to yielding health benefits, especially in terms of modifying risk factors for cardiovascular disease.  However, resistance (strength) training is quickly climbing the ranks, proving it has a role in a comprehensive exercise regimen to promote better health.  Its positive effects on muscle strength, endurance, and power in the general healthy population have been well established.

     In the past, its safety for those at risk for or who have established cardiovascular disease has been questioned.  This mindset has changed in recent years.  Resistance training is now accepted by health professionals to be part of a well-rounded exercise program for this population.  Benefits include: enhanced muscular endurance and strength, improved capability of performing daily activities, promotion of independence, and increased self-confidence.  

     The effects of resistance training on obesity and diabetes, two risk factors for cardiovascular disease, has been less well understood.  A study that reviewed this area of interest was published in the March/April 2009 issue of the Journal of Cardiopulmonary Rehabilitation and Prevention.  Researchers obtained literature that was published during 1950-2008 from the MEDLINE Plus/Ovid literature search system to determine the effects of resistance training on obesity and diabetes.  Findings of the review substantiate the positive role that resistance exericse plays in the management of blood sugar and obesity.

Effects of Resistance Exercise on Blood Sugar Control

• Enhances insulin sensitivity
• Improves glucose tolerance 
  
• Decreases levels of glycated hemoglobin concentrations (high levels of glycated hemoglobin are associated with high blood pressure, heart disease, and kidney failure in individuals with metabolic syndrome and diabetes)
• Effects of resistance exercise appear to be related to changes in the trained muscle as opposed to an increase in muscle size 

Effects of Resistance Exercise on Obesity

• Improves overall body composition in both men and women
• Increases resting metabolic rate
• Decreases body fat, including abdominal and visceral fat (excess levels of these in particular have been associated with an increased risk for developing the metabolic syndrome)
• Increases muscle size and strength which leads to a greater tolerance for longer durations of aerobic exercise, thereby increasing the caloric expenditure of the activity 

     The researchers of the review conclude that resistance training appears to aid in the management of diabetes and obesity and, therefore, should be part of a comprehensive exercise program.  Resistance exercises do not have to be limited to the use of machines and/or dumbbells but can include resistance bands/tubing, medicine balls, and even soup cans or milk jugs.  The federal government's 2008 Physical Activity Guidelines for Americans recommends that apparently healthy adults and older adults perform moderate- to high- intensity muscle strengthening exercises for the major muscle groups of the body at least twice a week. 

Note:  Before beginning an exercise program or increasing the intensity level of a current routine, a physician's approval should be obtained, especially for older adults and those at risk for or who currently have chronic health conditions.

Resources

Journal of Cardiopulmonary Rehabilitation, vol 29(2), March/April 2009, pp. 67-75; "Resistance Training in the Treatment of Diabetes and Obesity:  Mechanisms and Outcomes," Tresierras, M., Balady, G.

2008 Physical Activity Guidelines for Americans (www.health.gov/paguidelines)

ACSM's Guidelines for Exercise Testing and Prescription, Eighth Edition