For years, people with diabetes have been told that the key to controlling their blood-sugar levels is a combination of diet and aerobic exercise. Now, a new study by the All India Institute of Medical Sciences finds that muscle-building exercises through weight training also play a significant role in improving blood-glucose levels.
Increasing muscle strength “significantly improves insulin sensitivity, fasting glycaemia and decreases subcutaneous fat in type-2 diabetes in Asian Indians”, finds the study — the first of its kind in India.
Conducted on diabetics aged between 25 and 50, the study — by the departments of internal medicine, physiotherapy and radiodiagnosis at AIIMS — was accepted by the International Congress on Obesity held last week in Brisbane and will appear in the medical journal Diabetes.
“Since muscle is a major site for glucose metabolism, increasing muscle mass improves insulin sensitivity,” says lead author Dr Narendra Kumar from the department of medicine, AIIMS. Indians tend to have less lean muscle mass and a higher percentage of body fat, which is believed to predispose them to insulin sensitivity and diabetes. India has the largest number of diabetics — 35 million — in the world. The number is expected to double by 2020.
“Along with lowered blood-glucose levels, the study found that resistance training for 30 minutes a day for three months also lowered weight, levels of blood fats such as triglycerides, circumferences of the waist, arm and thigh, and most important, overall loss of subcutaneous fat, which is the biggest culprit for diabetes and heart disease in Indians,” says Dr Anoop Misra, who guided the AIIMS study but is now with the Fortis group of hospitals.
Resistance training includes free weights, weight machines and calisthenics such as chin-ups, push-ups, and sit-ups. Apart from boosting cardiovascular health, resistance training improves the metabolic rate and helps burn more calories.
For the AIIMS study, doctors tracked such biomedical parameters as fasting blood glucose, HbA1c (a three-month average glucose reading), lipid profile and insulin sensitivity. All parameters improved, although changes in cholesterol levels were not significant, says Dr Kumar.
"People with diabetes are usually prescribed aerobic exercises such as brisk walks to lose weight, but resistance exercises to improve impaired glucose tolerance is a subject that has been sparsely studied, even in the West," says Dr Misra. "Based on this study, we recommend 20 to 30 minutes of exercise including weight training for Indians for effective diabetes management."