Aerobic and resistance training effects compared to aerobic training alone in obese type 2 diabetic patients on diet treatment
Introduction
Aerobic exercise has shown many positive effects on insulin sensitivity and glucose homeostasis [1]. A chronic aerobic training (AT), even without changes in body composition, improves insulin sensitivity up to 30% both in impaired glucose tolerant (IGT) and type 2 diabetic patients [1]. Exercise intervention in adults with type 2 diabetes induces a mean fall in HbA1c percentage of 0.74 compared with control group, independently to body weight change [2]. In addition it promotes mobilization of visceral adipose tissue so reducing insulin resistance [3]. AT improves as well some cardiovascular risk factors such as hypertension, dyslipidemia and fibrinolytic activity [4]. According to these benefits daily AT was listed in guidelines for exercise in type 2 diabetes [5].
Resistance training (RT) shows potential benefits in rehabilitation, thanks to its ability in avoiding disease-related muscle wasting. Further, muscle contraction increases glucose uptake and improves insulin sensitivity in skeletal muscle thereby providing a rationale for its use in disease like type 2 diabetes [6], [7]. RT enhances muscular strength and changes in body composition by increasing lean body mass and decreasing visceral and total body fat [8]. In particular, light to moderate loads (40–60% of 1 RM) are recommended for local muscular endurance training performed at high repetition using short resting period (<90 s) [9]. In addition, 3 days per week (3 d w−1) training frequency has been recently shown to be superior to 1–2 days per week for improving muscular endurance, coordination, balance and cardiorespiratory fitness in older women [10], confirming meta-analytical data showing that strength gains in untrained individuals were highest with a frequency of 3 d w−1 [11]. In this light, recently published studies investigating the effect of aerobic and resistance training in patients with cardiovascular disease like chronic heart failure and stroke, adopted a 5 d w−1 training frequency in order to provide further evidence for the use of exercise as a clinical therapy in these patients [12], [13].
Actually, few studies investigated the effect of a short program (about 3 weeks) of combined high frequency AT plus RT on glucose homeostasis and insulin sensitivity. In particular, there is small evidence of additional benefit from combining RT and AT on some related risk factors for diabetes complications (endothelial function and sub-clinical inflammation) in obese type 2 diabetic patients [14].
Therefore, the present study was designed to evaluate the effects of a short high frequency (5 d w−1) RT and AT added to a program of hypocaloric diet compared with a high frequency AT with a similar program of hypocaloric diet, on fat and lean body mass distribution, glucose levels, insulin levels and sensitivity, endothelial factors, adipokines and pro-inflammatory markers releases in obese type 2 diabetic patients.
Section snippets
Informed consent
Fifty middle-aged patients (30 males, 20 females) were included in the experimental protocol. All patients gave informed consent to participate into the study that was approved by the local Ethics Committee.
Study population
Patients were severely obese (body mass index, 38.6 ± 5.6; waist circumference, 113.1 ± 12.7 cm), with type 2 diabetes mellitus and metabolic syndrome according to ATPIII [15]. Before hospitalization, all were treated by diet alone for type 2 diabetes and the 2 study groups had comparable
Diet program
Patients were hospitalized for 21 days and submitted to a hypocaloric diet regime that consisted of 1000 kcal/day with 55% carbohydrate, 25–30% fat (saturated fat 7%) and 15–20% protein (animal protein 54 g) subdivided as follows: 15% for breakfast, 50% for lunch and 35% for dinner, administered under a daily supervision of a dietician. Diet was controlled not only for carbohydrate but also for cholesterol and natural fiber content (176 mg and 25 mg, respectively).
The diet provided about 50% of
Results
Three patients of AT group withdrawn the study and all the results are related to 47 patients, i.e. 27 patients in AT group and 20 patients in ART group and in Table 1 are reported anthropometric parameters, systolic and diastolic blood pressure, lipids levels and glucose metabolism measurements for these patients. Before training period, no statistically significant differences in anthropometric and metabolic variables were observed between the two groups as shown by Student's t-test (Table 1
Discussion
The present study investigates the effects of high frequency resistance exercise added to an aerobic exercise intervention carried on in controlled conditions as add-on to a strict diet regime administered under a daily supervision of a dietician in a population of obese type 2 diabetic patients; results observed after 3 weeks of therapy show at least three major aspects that need to be discussed: (1) a combination of aerobic and resistance high frequency exercise training improves overall
Conflict of interest
There are no conflicts of interest.
Acknowledgment
The excellent technical support of Ms. Sabrina Costa and Barbara Fontana is gratefully acknowledged.
References (46)
- et al.
Effects of exercise frequency on functional fitness in older adult women
Arc Gerontol Geriatr
(2007) - et al.
The effect of aerobic versus resistance exercise training on peak cardiac power output and physical functional capacity in patients with chronic heart failure
Int J Cardiol
(2010) - et al.
Obesity in older adults: technical review and position statement of the American Society for Nutrition and NAASO, The Obesity Society
Am J Clin Nutr
(2005) - et al.
Age-predicted maximal heart rate revisited
J Am Coll Cardiol
(2001) - et al.
The adipose triglyceride lipase, adiponectin and visfatin are downregulated by tumor necrosis factor-alpha (TNF-alpha) in vivo
Cytokine
(2009) - et al.
Anti-inflammatory effect of exercise training in subjects with type 2 diabetes and the metabolic syndrome is dependent on exercise modalities and independent of weight loss
Nutr Metab Cardiovasc Dis
(2010) - et al.
Aerobic exercise, but not flexibility/resistance exercise, reduces serum IL-18, CRP, and IL-6 independent of beta-blockers, BMI, and psychosocial factors in older adults
Brain Behav Immun
(2006) - et al.
Improved endothelial function following a 14-month resistance exercise training program in adults with type 2 diabetes
Diab Res Clin Pract
(2008) - et al.
Influence of physical training on blood glucose control, glucose tolerance, insulin secretion, and insulin action in non-insulin-dependent diabetic patients
Diab Care
(1984) - et al.
Effects of exercise on glycemic control and body mass in type 2 diabetes mellitus: a meta-analysis of controlled clinical trials
JAMA
(2001)