Effects of resistance training on metabolic profile of adults with type 2 diabetes.
Type 2 diabetes
Weight training (Analysis)
|Publication:||Name: Indian Journal of Medical Research Publisher: Indian Council of Medical Research Audience: Academic Format: Magazine/Journal Subject: Biological sciences; Health Copyright: COPYRIGHT 2009 Indian Council of Medical Research ISSN: 0971-5916|
|Issue:||Date: May, 2009 Source Volume: 129 Source Issue: 5|
|Product:||Product Code: E121940 Adults|
Background & objectives: The number of diabetes in India is
increasing at an alarming rate. The effects of physical activity in the
form of resistance training or aerobic exercises on type 2 diabetes have
not been studied in Indian population. The objective of this study was
to analyse the effects of eight weeks of progressive resistance training
(PRT) compared with aerobic exercise (AE) on glycaemic control,
metabolic profile, cardiovascular fitness parameters and general well
being in adults with type 2 diabetes.
Methods: Thirty adults (14 females and 16 males mean; age 53.8 [+ or -] 8.8 yr) with type 2 diabetes were randomly assigned to 8 wk supervised PRT (n=10) or AE (n=10) or control group (n=10). Glycosylated haemoglobin (HbA1c), lipid profile, blood pressure, heart rate, body mass index (BMI) and general well being were measured before training (i.e. 0 wk) and after 8 wk of training period.
Results: Plasma glycosylated haemoglobin levels decreased significantly (P<0.05) both in the PRT group (7.57 [+ or -] 2.4% to 6.23 [+ or -] 0.8%) and in AE group (8.11 [+ or -] 0.9% to 6.66 [+ or -] 0.9%).Total cholesterol levels decreased significantly (P<0.05) by 13.3 per cent in PRT group and by 6.1 per cent in AE group. Both exercise groups showed significantly reduction in systolic blood pressure (P<0.05). General well being improvement was much more in PRT (8.6%) as compared to AE group (2.7%).
Interpretation & conclusions: Our findings showed that both PRT and AE were effective in improving metabolic profile of adults with type 2 diabetes but the percentage improvement in triglycerides, total cholesterol levels and general well being with PRT was more compared to AE. Further studies on a larger sample need to be done to confirm these findings.
Key words Aerobic exercise--diabetes--glycaemic control--metabolic profile--progressive resistance training
India leads the world with largest number of diabetic subjects earning the dubious distinction of being termed the "diabetes capital of the world." (1) The so called "Asian Indian Phenotype" refers to certain unique clinical and biochemical abnormalities in Indians which include increased insulin resistance, greater abdominal adiposity i.e., higher waist circumference despite lower body mass index, lower adiponectin and C-reactive protein levels. This phenotype makes Asian Indians more prone to diabetes and premature coronary artery disease (1). According to the Diabetes Atlas (2) published by the International Diabetes Federation, the number of people with diabetes in India is currently around 40.9 million and is expected to rise to 69.9 million by 2025 unless urgent preventive steps are taken. Proper management can offset many complications that can occur with diabetes. Regular physical exercise is an intervention that can improve the health of individuals with diabetes; particularly those with type 2 diabetes (T2D).
The American Diabetes Association (ADA) recommends that individual with type 2 diabetes perform at least 150 min of moderate intensity aerobic exercise or at least 90 min of vigorous aerobic exercise per week (19). Aerobic exercise has consistently been shown to improve glucose control, enhance insulin sensitivity and reduce cardiovascular risk factors such as visceral adiposity, lipid profile, arterial stiffness and endothelial function (4). However, for many older patients with type 2 diabetes, the presence of diabetic complications or coexisting conditions such as obesity, degenerative arthritis or cardiovascular disease may preclude participation in aerobic activities (5). Resistance training has recently been recognized as a therapeutic tool for the treatment of a number of chronic diseases and has been demonstrated to be safe and efficacious for the elderly and obese individuals. Similar to aerobic exercise, resistance training may enhance insulin sensitivity, daily energy expenditure and quality of life (4).
In spite of the benefits of the exercises on type 2 diabetics, no information is available on the effects of exercises in patients with diabetes in India. This study was therefore undertaken to observe the effects of both progressive resistance training (PRT) as well as aerobic exercise (AE) on glycaemic control, metabolic profile and cardiovascular fitness parameters in the Indian patients with type 2 diabetes.
Material & Methods
Thirty type 2 diabetic outpatients (14 females and 16 males) participated in this study. The study protocol was given approval by the Medical Ethics Committee of the Guru Nanak Dev University, Amritsar, Punjab. Subjects were recruited from University Health Centre, Guru Nanak Dev University, Amritsar during June and October 2007. Inclusion criteria were as follows: established type 2 diabetes (>6 months duration), an inactive lifestyle, no strength training in preceding 1 yr, not taking insulin, males or females aged between 40 to 70 yr. Eligible subjects went under a physical examination and medical screening to exclude individuals with subjective or objective evidence of coronary artery disease, uncontrolled hypertension, advanced retinopathy or neuropathy, severe orthopaedic/ cardiovascular/respiratory conditions restricting physical activity. Subjects were randomly assigned to one of the three groups: progressive resistance training (PRT) group (n=10), aerobic exercise (AE) group (n=10) or control group (n=10) (Table I). All subjects gave their written informed consent to participate in the study.
The subjects were tested on two occasions using identical protocols. Baseline measurements were taken before the intervention and post study all the measurements were taken again.
Glycemic and metabolic outcomes: Plasma glycosylated haemoglobin (HbA1c) concentration was the main outcome for glycaemic control. HbA1c was analyzed using NycoCard HbA1c test (NycoCard reader II).
Serum cholesterol, HDL (high density lipoprotein) cholesterol and triglyceride levels were measured by Bayer's semi automatic analyser using standard procedures.
Anthropometrics: Body weight was measured to the nearest 0.1 kg using weighing machine (Acto Inc., India) and height to the nearest 0.25 cm using anthropometric rod. Body mass index (BMI) was determined by body weight and height as kg/[m.sup.2].
Cardiovascular fitness parameters: Blood pressure was measured using Lifecare[TM] sphygmomanometer (N & B Medical Products Co., India) and heart rate (HR) was monitored using Polar $410[TM] heart rate monitor (CE0537, Finland).
Psychological profile: 22-items self administered well being questionnaire of Bradley and Lewis was used to assess the psychological well being among all subjects as general well being score (GWBS) (20).
PRT group: Subjects performed systematic supervised resistance training in line with the ADA (American Diabetes Association) (10) and ACSM (American College of Sports Medicine) (7) guidelines. Subjects exercised at the University Health Centre, two times per week. Each session started with a 5 min warm up (static cycling) followed by seven exercises for major muscle groups-biceps, triceps, upper back, abdominals, knee flexors and extensors; using dumbbells, pulleys, lateral pull down and quadriceps table. Subjects performed 3 sets of i0 repetitions of each exercise per session. This was followed by 5 min cool down (static cycling). The PRT protocol was designed to provide progressive increase in intensity. At 0 wk, 1RM (repetition maximum) was calculated for each exercise using Brzycki's equation (8). 1RM is a dynamic procedure for measuring muscle strength. 1RM refers to the maximum amount of weight lifted one time using proper form during a standard weight lifting exercise (9). Training started with 60 per cent of 1RM and was progressed to 100 per cent of 1RM during the 8 wk training period.
Pre- and post-exercise blood pressure and heart rate were monitored. Subjects were advised regarding eating 1-2 h before exercise to avoid hypoglycaemia, maintaining hydration levels, knowing the signs and symptoms of hypoglycaemia. Nine out of ten subjects completed the training protocol.
Aerobic exercise group: Subjects performed walking as the aerobic exercise for 30 min per day thrice a week for 8 wk.
Control group: Subjects went under no training but continued with medications and any nutritional advice that they were following.
Statistical analysis: Initial baseline measurements were analyzed by ANOVA to determine differences between the groups before intervention. The post-training changes were compared between groups by ANOVA. Statistical tests were performed using SPSS Software (SPSS 14.0).
The exercise training programme was safely done by all subjects except for one dropout in PRT group due to time constraints. No exercise related injuries and hypoglycaemic events were reported.
Subjects in both PRT and AE groups showed significant (P<0.05) decrease in plasma glycosylated haemoglobin levels. In terms of percentage, PRT group showed 17.7 per cent decrease and AE group showed 17.9 per cent reduction in HbA1c levels. HDL levels did not change between groups. Triglycerides level decreased by 22.2 per cent in PRT group as compared to 6.9 per cent in AE group and 7.5 per cent decrease in control group. Total cholesterol level significantly decreased in PRT group and in AE group (P<0.05), (Table II). BMI did not change significantly in all three groups after 8 wk.
Systolic blood pressure (SBP) was significantly lowered in PRT and in AE groups by 6.5 and 6.2 per cent respectively as compared with control subjects (P<0.05). There was no significant change in diastolic blood pressure (DBP) and heart rate. General well being was assessed by well being questionnaire with a maximum score of 66 and showed a 8.6 per cent increase in score in the PRT group (P<0.05) compared to 2.7 and 2 per cent increase in score in AE and control groups respectively (Table II).
Our study showed that both the PRT and AE groups showed significant improvement in HbA1c, total cholesterol levels, systolic blood pressure and psychological profile as compared to control group, but the percentage improvement in PRT group, for total cholesterol levels and general well being was better compared to the AE group. Literature on exercise training showed a modest response (0.5 to 1.0%) or no response on HbA1c levels to training interventions (11). Another study found no significant reduction in HbA1c after 5 months of progressive circuit training (12). Non significant changes in HbA1c were attributed to short duration of training i.e., 4-6 wk (13). Castenda et al (14) reported significant improvement in HbA1c with 4 months high intensity PRT. This showed that HbA1c improvement occurred with resistance training or aerobic exercise if done for long duration (3-4 months), in contrast, in the present study improvements were seen with only 8 wk of training, could be attributed to the subjects never subjected to any kind of training earlier. Another finding related to the HbA1c levels is that individuals with higher levels of HbA1c at baseline showed greater reduction than those individuals who had comparatively lower levels. Also Asian Indians have excessive insulin resistance compared to Europeans (15). So, it is thought that Asian Indians with excessive insulin resistance showed much more improvement than their European counterparts. This study did not analyse the mechanisms involved in the better response in Indians. Possible explanation can be that plasma membrane GLUT4 (glucose transporter) is increased in skeletal muscle from individual with type 2 diabetes in response to an acute bout of exercise. Also lower resting plasma membrane GLUT4 content in insulin resistant subjects have been observed in some studies (16).
The decrease in the total cholesterol and triglyceride levels IS important in preventing macrovascular complications. The improvement seen in lipid profile was more in PRT group than in AE group which can be related to better improvement of cardiovascular fitness parameters seen in PRT group. In earlier studies, safety of PRT in older adults, including those with coronary artery disease is documented, suggesting that PRT may be preferable to aerobic training (17). Our findings also support this.
It was found that general well being though improved in both the exercise groups, more improvement was seen in PRT group which may be because this group received the maximum contact time. It also supports the psychological benefits of the exercises.
Our study had a limitation that the control subjects received medications only and did not interact with exercise trainers while the subjects in the two exercise groups interacted with trainers which could have influence on the psychological well being of these subjects but could not be ruled out.
Despite this limitation, this study showed that both high intensity low volume PRT and aerobic exercise were effective in improving glycaemic control, metabolic profile, cardiovascular fitness and general well being of subjects with T2D. The small sample size in each group was another limitation of the study.
Further study is needed to confirm these findings on a properly designed study with a large sample.
This study was funded by a grant from University Grants Commission (UGC), Delhi, India. Authors thank Dr Anand's Path Lab, Green Avenue, Amritsar for analyzing the blood samples for HbA1c and Drs H.P. Singh and Sunil Kumar for assistance.
Received November 1, 2007
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Reprint requests: Dr Shweta Shenoy, Department of Sports Medicine & Physiotherapy, Guru Nanak Dev University Amritsar 143 001, India e-mail: shwet firstname.lastname@example.org
Ekta Arora, Shweta Shenoy & J.S. Sandhu
Department of Sports Medicine & Physiotherapy, Guru Nanak Dev University, Amritsar, India
Table I. Baseline demographic data (mean [+ or -] SD) of the control and study groups Control Progressive group resistance training (PRT) group Number (M : F) 10 (6 : 4) 10 (4 : 6) Age (in yr) 58.4 [+ or -] 1.8 49.6 [+ or -] 5.2 Duration of diabetes (yr) 5.2 [+ or -] 2.9 5.4 [+ or -] 1.5 Number of participants treated with Diet only 0 2 Oral Drugs 10 8 BMI (kg/[m.sup.2]) 24.98 [+ or -] 3 26.99 [+ or -] 4.1 Aerobic exercise (AE) group Number (M : F) 10 (6 : 4) Age (in yr) 52.2 [+ or -] 9.3 Duration of diabetes (yr) 4.7 [+ or -] 1.7 Number of participants treated with Diet only 4 Oral Drugs 6 BMI (kg/[m.sup.2]) 26.23 [+ or -] 3.2 Table II. Changes in the glycaemic control, metabolic profile, cardiovascular fitness parameters and general well being score (GWBS) values (mean [+ or -] SD) in all the three groups at 0 wk and after 8 wk of training Dependent variable Control group, Control group, 0 wk 8th wk Number of subjects 10 10 HbA1c (%) 7.77 [+ or -] 0.9 7.41 [+ or -] 0.9 HDL (mg/dl) 52 [+ or -] 13.5 51 [+ or -] 12.3 Triglycerides (mg/dl) 179 [+ or -] 41.4 165 [+ or -] 36.5 Total cholesterol (mg/dl) 188 [+ or -] 19.4 190 [+ or -] 22.9 SBP (mm of Hg) 131 [+ or -] 6.4 129 [+ or -] 6 DBP(mm of Hg) 84 [+ or -] 4.4 83 [+ or -] 3.5 Heart rate (Beats/min) 84 [+ or -] 5.3 84 [+ or -] 3.2 BMI (kg/[m.sup.2]) 25 [+ or -] 13 25.1 [+ or -] 3.1 GWBS 40 [+ or -] 6 40 [+ or -] 6 Dependent variable PRT group, PRT group, 0 wk 8th wk Number of subjects 10 9 HbA1c (%) 7.57 [+ or -] 1.4 6.23 [+ or -] 0.8 * HDL (mg/dl) 53 [+ or -] 9.9 54 [+ or -] 9.1 Triglycerides (mg/dl) 179 [+ or -] 50.3 139 [+ or -] 18.9 Total cholesterol (mg/dl) 188 [+ or -] 16.6 163 [+ or -] 15.4 * SBP (mm of Hg) 126 [+ or -] 6.8 118 [+ or -] 5.1 * DBP(mm of Hg) 82 [+ or -] 3.6 77 [+ or -] 4.1 Heart rate (Beats/min) 90 [+ or -] 8.3 84 [+ or -] 7.8 BMI (kg/[m.sup.2]) 27 [+ or -] 4.1 26.8 [+ or -] 4.1 GWBS 44 [+ or -] 5 48 [+ or -] 6 * Dependent variable AE group, AE group, 0 wk 8th wk Number of subjects 10 10 HbA1c (%) 8.11 [+ or -] 0.9 6.66 [+ or -] 0.9 HDL (mg/dl) 51 [+ or -] 10.2 53 [+ or -] 10.4 Triglycerides (mg/dl) 160 [+ or -] 28.2 149 [+ or -] 22.6 Total cholesterol (mg/dl) 183 [+ or -] 25.2 172 [+ or -] 19.5 SBP (mm of Hg) 132 [+ or -] 8.5 124 [+ or -] 11.6 DBP(mm of Hg) 84 [+ or -] 5.3 81 [+ or -] 8.2 Heart rate (Beats/min) 87 [+ or -] 6.8 86 [+ or -] 6.8 BMI (kg/[m.sup.2]) 26.2 [+ or -] 3.2 25.8 [+ or -] 3.8 GWBS 41 [+ or -] 5 42 [+ or -] 4 * P<0,05; SBP, systolic blood pressure; DBP, diastolic blood pressure; GWBS, general well being score
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