|Year : 2014 | Volume
| Issue : 2 | Page : 54-59
Blood glucose response to aerobic exercise training programme among patients with type 2 diabetes mellitus at the University of Nigeria Teaching Hospital, Enugu South-East, Nigeria
Charles Ikechukwu Ezema1, Amarachi A. Onwunali1, Sikiru Lamina2, Uche A. Ezugwu3, Augustine A. Amaeze3, Maduabuchukwu Joseph Nwankwo4
1 Department of Medical Rehabilitation, Faculty of Health Sciences and Technology, University of Nigeria, Enugu Campus, Enugu, Nigeria
2 Department of Biomedical Technology, School of Health Technology, Federal University of Technology, Owerri, Nigeria
3 Department of Physiotherapy, University of Nigeria Teaching Hospital, Ituku Ozalla, Enugu State, Nigeria
4 Department of Medical Rehabilitation, Nnamdi Azikiwe University, Anambra State, Nigeria
|Date of Web Publication||13-Jun-2014|
Department of Biomedical Technology, School of Health Technology, Federal University of Technology, Owerri
Background: Control of diabetes involves maintaining normal or near normal blood glucose levels through appropriate therapy: insulin, oral hypoglycemic agents, diet and exercise. The aim of this study was to investigate the blood glucose response to aerobic exercise training among subjects with type 2 diabetes mellitus (T2DM) at University of Nigeria Teaching Hospital (UNTH), Enugu. Materials and Methods: Subjects with diagnosis of T2DM attending the diabetes clinic of the UNTH participated in the study. A total of 54 subjects with T2DM (fasting blood sugar [FBS] of between110 and 225 mg/dl) were randomized into two age matched groups: Exercise (n = 30) and control (n = 24) groups. The exercise group involved in an 8 week continuous training (60-79% heart rate [HR] max) of between 45 and 60 min, 3 times/week, while the controls group remain sedentary. Systolic blood pressure (SBP), diastolic blood pressure (DBP), aerobic fitness (VO 2 max) and FBS were assessed. Analysis of covariance and Pearson correlation tests were used in data analysis. Results: We observed significant effect of exercise training program on, SBP (P = 0.000), DBP (P = 0.007), FBS (P = 0.001) and VO 2 max (P = 0.013). Changes in VO 2 max significantly and negatively correlated with changes in FBS (r = −0.220) at P < 0.05. Conclusion: It was concluded that aerobic exercise program is an effective adjunct in controlling blood glucose level among type 2 diabetic subjects.
Keywords: Aerobic exercise, blood glucose, type 2 diabetes mellitus
|How to cite this article:|
Ezema CI, Onwunali AA, Lamina S, Ezugwu UA, Amaeze AA, Nwankwo MJ. Blood glucose response to aerobic exercise training programme among patients with type 2 diabetes mellitus at the University of Nigeria Teaching Hospital, Enugu South-East, Nigeria. Sahel Med J 2014;17:54-9
|How to cite this URL:|
Ezema CI, Onwunali AA, Lamina S, Ezugwu UA, Amaeze AA, Nwankwo MJ. Blood glucose response to aerobic exercise training programme among patients with type 2 diabetes mellitus at the University of Nigeria Teaching Hospital, Enugu South-East, Nigeria. Sahel Med J [serial online] 2014 [cited 2021 Jun 19];17:54-9. Available from: https://www.smjonline.org/text.asp?2014/17/2/54/134476
| Introduction|| |
The etiology of type 2 diabetes mellitus (T2DM) is unknown, but several studies indicate that the disease results from a combination of genetic susceptibility and external risk factors. , According to this multifactorial model, genetically predisposed subjects will not necessarily develop overt disease unless they are also exposed to particular environmental factors. , Important risk factors for the development of T2DM, apart from obesity, include a family history of diabetes, increased age, hypertension, lack of physical exercise and ethnic background. ,
World Health Organization (WHO) data in 2000 showed that approximately 117 million people had DM world-wide and it was postulated that this number might rise to 370 million by the year 2030.  The WHO report also revealed that a larger percentage of this increase will occur in developing countries especially Africa due to population growth, ageing, unhealthy diets, obesity and sedentary life-style.  Treatment of diabetes includes a combination of exercise, proper diet, medication and daily self-care.  Aerobic exercise has consistently been shown to improve glucose control, enhance insulin sensitivity and improve cardiovascular risk factors such as visceral adiposity, lipid profile, arterial stiffness and endothelial function.  The American Diabetes Association recommends that individuals with T2DM perform at least 150 min of moderate intensity aerobic exercise and/or at least 90 min of vigorous aerobic exercise/week.  Some studies ,,, have shown interracial, interpersonal and ethnic variation in susceptibility of T2DM. It has also been reported that genetics play a major role in a person's VO 2 max and that heredity account for up to 25-50% of the variance seen between individuals.  It is however, unclear whether genetic and other factors could affect response to exercise in T2DM subjects. The purpose of the present study was to investigate the effect of continuous training program on blood sugar and blood pressure (BP) in a black African population with T2DM.
| Materials and methods|| |
The subjects comprised of 54 (27 male and 27 female) adults with diagnosis of T2DM who were attending diabetes clinic of University of Nigeria Teaching Hospital (UNTH), Enugu. Their age ranged between 40 and 55 years. Subject were fully informed about the experimental procedures, risk and protocol, after which they gave their informed consent in accordance with the American College of Sports Medicine (ACSM) guidelines,  regarding the use of human subjects. Ethical approval was granted by the research and ethics committee of the UNTH, Enugu.
All procedures were conducted at the Physiotherapy Department of UNTH, Enugu, Nigeria. The diabetes subjects were assigned to age and sex-matched exercise and control groups. The exercise group was involved in a continuous training program for 8 weeks while the control group remained sedentary during the period. At the end of training and sedentary period a post-test procedure was administered to all subjects.
Only those who volunteered to participate in the study and were all stable, without any cardiac complications were recruited. Their BP (BP<140/90) was within normal range. Only those treated with on diet and/or oral agents were recruited. They were sedentary and have no history of psychiatry or psychological disorders or abnormalities.
Smokers, alcoholic, subjects with uncontrolled hyperglycemia (>250 mg/dl) and severely elevated BP (resting BP >200/115), cardiac, renal, respiratory disease and subjects on insulin therapy were excluded. Those involved in vigorous physical activities and above averagely physically fit were also excluded.
A total of 61 T2DM subjects satisfied the study criteria.
Subjects resting heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were monitored from the right arm as described by Musa et al.  using an automated digital electronic BP monitor (Omron Digital BP Monitor, Model 11 EM 403c; Tokyo Japan).
Subjects' anthropometric characteristics (weight [kg] and height [m]) and (body mass index [BMI] [kg/m 2 ]) assessment ware done in accordance with standardized protocol. 
Fasting plasma blood glucose
Subject's pre- and post-training fasting plasma glucose level was measured using the Accucheck glucometer before the exercise training and after the 8 weeks exercise training under the supervision of a medical laboratory scientist from the Medical Laboratory Science Department of UNTH, Enugu.
The Young Men Christian Association (YMCA) sub-maximal cycle ergometry test protocol was used to assess the subject's aerobic power as described by ACSM,  Golding et al.  The YMCA protocol uses two to four 3 min stages of continuous exercise. Two HR-power output data points (two steady state HR) of between 110 and 150 beat/min were needed. The bicycle seat height was adjusted and the subjects' knee slightly flexed when the pedal was in the down position. Exercise test started with a 2-3 min warm up at zero resistance in order to acquaint the subjects with the cycle ergometer. According to Brook et al.;  Pollock and Wilmore  middle aged, less fit, cardiac patient generally begins at 100 or 150-300 kg/min (17 W or 25 W to 50 W respectively) with power increments of 5-25 W/stage.
The first 3 min work rate was set between 100 and 150 kg (17-25 watts), (1 W = 6 kg/min). The pedal speed was set at 50 rpm (revolutions/min) by setting the metronome at 100 bpm (beats/min), HR was measured within the last minute of each stage. When a HR of above 110 bpm was obtained in the first 3 min, then only one additional 3 min stage was performed by increasing the workload by either 30 or 150 kg. If the second stage HR was less than 110 bpm, then 3 rd or 4 th Stage 3 min was performed at additional workload of 30 or 150 kg up to 300 kg in order to obtain two HR between 110 and 150 bpm. These two HR should not differ by more than 5 bpm; when they did, the test was extended by another minute or until a stable value was obtained. At the end of the test, another 2-3 min recovery period (cool down) at zero resistance pedaling was administered.
The two steady state HR was plotted against the respective workload on the YMCA graph sheet. A straight line was draw through the two points and extended to the subjects predicted maximum HR (220 age). The point at which the diagonal line intersects the horizontal (predicted HR max) line represents the maximal working capacity for the subject (HR max). A perpendicular line was dropped from this point to the baseline where the maximal physical workload capacity was read in kg/min, which was used to predict the subjects VO 2 max. This procedure was done for both pre- and post-test stress test. 
Exercise group (group 1)
After a 10 min warm up (pedaling at zero resistance), subjects in the exercise group exercised on a bicycle ergometer at a moderate intensity of between 60% and 79% of their HR max. , The starting workload was 100 kg (17 W), which was increased at a pedal speed of 50 rpm to obtain a HR max 60% was increased in the first 2 weeks to and level up at 79% HR max throughout the remaining part of the training period lacks. The initial of exercise session was increased from 45 min in the first 2 weeks of training to and leveled up at 60 min throughout the remaining part of the training. After each training session, 10 min cool down was established by pedaling at zero resistance. Exercise session of 3 times/week was also maintained throughout the 8 weeks training period.
The control group (group 2)
Subjects in the control group were instructed not to undertake any organized/structured physical activity apart from the activity of daily living during the 8 weeks period of study.
Post-training SBP, DBP, VO 2 max, stress test and fasting blood sugar (FBS) were conducted as earlier described in the pre-test procedures using standardized protocols. All pre- and post-test measurements were recorded on a data sheet. In 8 weeks training program, 54 subjects(30 from continuous and 24 from the control group) were completed. Seven subjects (one from exercise and six from the control group) had dropped out because of non-compliance and incomplete data; therefore, the data of 54 subjects were used in the analyses [Figure 1].
The descriptive statistics (means and standard deviations [SD]) of the subjects physical characteristics, BP, VO 2 max and FBS were determined. Analysis of covariance (ANCOVA) was used to assess treatment outcomes. In the ANCOVA, the post-test values were the outcome variables and baseline characteristics that as covariates. Pearson product moment correlation test was used to determine the relationship between the estimated changes in VO 2 max (changed score) and FBS. All statistical analysis was performed using the statistical package for the social science, (version 16.0 Chicago IL, USA). The probability level for all the above tests was set at 0.05 to indicate significance.
| Results|| |
The diabetes subject's mean ± age was 47.35 ± 4.55 years age ranged between 40 and 55 years. Mean (SD) age and BMI of subjects in the exercise group were 47.53 [4.68] years and 22.60 [0.93] kg/m 2 , respectively while for the control group mean (SD) age and BMI were 47.13. (4.48) years and 23.06 (0.86) kg/m 2 , respectively. Detailed physical characteristics' of subjects are shown in [Table 1].
|Table 1: Comparison of baseline characteristics of subjects and controls|
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ANCOVA tests and groups' pre- and post-treatment mean BP (SD) mmHg; FBS (mg/dl) and VO 2 max (ml/kg/min) are depicted in [Table 2]. ANCOVA analysis indicated a significant difference in groups' pre- and post-treatment SBP (F = 31.377, P = 0.000) DBP (F = 9.004, P = 0.007) FBS (F = 26.597, P = 0.000) and VO 2 max (F = 6.643, P = 0.013).
There was a significant negative correlation between changes between VO 2 max and changes in FBS (r = −0.252) at P < 0.01 [Figure 2].
|Figure 2: Correlation between training changes in VO2 max and fasting blood sugar (N = 30)|
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| Discussion|| |
Findings from the present study revealed a significant decrease in SBP, DBP, FBS and increase in VO 2 max in the exercise group over the control group. Our data also indicated a significant negative correlation between changes in VO 2 max and changes in FBS. The favorable changes resulting from aerobic training in both SBP and DBP is consistent the reports of several other studies. ,,,
A similar study was conducted by Kadoglou et al.  in 2007 who investigated the effect of aerobic exercise training on glucose control in diabetes mellitus. They concluded that the aerobic exercise training without significant weight loss improves metabolic profile and exerts anti-inflammatory effects in patients with T2DM.
Gordon et al.  conducted a prospective randomized study to investigate the efficacy of Hatha yoga and aerobic exercise. In their study, 77 subjects with type 2 diabetic in the Hatha yoga exercise group were matched with a similar number of type 2 diabetic patients in the conventional aerobic exercise and control groups. Fasting blood glucose (FBG) was determined at baseline and at two consecutive 3 monthly intervals. They reported a significant reduction in the concentrations of FBG in the Hatha yoga and conventional aerobic exercise groups after 6 months. FBG decreased by 29.48% and 27.43% respectively (P < 0.0001). They demonstrated the efficacy of Hatha yoga exercise and conventional aerobic exercises on in patients with type 2 diabetes and suggest that Hatha yoga exercise and conventional aerobic exercise may have therapeutic preventive effects on diabetes mellitus.
Boulé et al.  in a meta-analysis investigated the effects of aerobic exercise on glycemic control in T2DM. They selected studies that evaluated the effects of exercise interventions (duration 8 weeks) in adults with T2DM. 14 (11 randomized and 3 nonrandomized) controlled trials were included. They concluded that exercise training reduces glycosylated hemoglobin by an amount that should decrease the risk of diabetic complications compared with control groups.
The mechanism of blood glucose reduction by aerobic training could be linked to three major pathways: The acute stimulation of muscle glucose transport pathway; acute enhancement of insulin action; and long-term up-regulation of the insulin signaling pathway resulting from regular exercise training. ,, The probable reason for the significant reduction in FBS in the exercise group over the control group might not be unconnected to the fact that aerobic bouts of exercise training may help train the motor units, enhancing the anaerobic and aerobic energy systems. This may lead to more effective utilization of fats and carbohydrates. 
| Conclusion|| |
The present study supports the recommendations of moderate intensity (continuous) training program as an adjunct non-invasive management of T2DM and dual therapeutic down-regulation effects on BP.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]