|Year : 2015 | Volume
| Issue : 1 | Page : 1-7
Changes in stress index, blood antioxidants and lipid profile between trained and untrained young female adults during treadmill exercise test: A comparative study
Awobajo Funmileyi Olubajo1, Olawale Olajide Ayinla2, Agiode Margaret1, Adegoke Olufeyisipe Adefunke1
1 Department of Physiology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Lagos, Nigeria
2 Department of Physiotherapy, Faculty of Clinical Sciences, College of Medicine, University of Lagos, Lagos, Nigeria
|Date of Web Publication||4-Jun-2015|
Awobajo Funmileyi Olubajo
Department of Physiology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Lagos
Source of Support: None, Conflict of Interest: None
Background: Having regular exercise has been linked to healthy living. However, exercise is also a stressor. How the body maintain homeostasis in the phase of changing blood chemistry during exercise has been the subject of many discussions. Aim: This study investigated the changes in blood pressure parameters, changes in blood glucose, cortisol, lipids, testosterone and blood free radicals, in exercise-trained young female adults and those living a sedentary lifestyle during a treadmill exercise test. Materials and Methods: Trained and untrained-participants were recruited for this study using predetermined criteria. Basal parameters such as height waist circumference, blood pressure, heart rate, blood glucose, lipid profile as well as antioxidant status were measured prior to and immediately after treadmill exercise test. Results: The results showed a significant (P ≤ 0.05) reduction in plasma level of glutathione (trained 0.040 ± 0.006, untrained 0.088 ± 0.035 ΅mol/ml), catalase (trained 0.909 ± 0.057, untrained 1.079 ± 0.024 mg/ml), malondialdehyde (MDA) (trained 0.062 ± 0.012, untrained 0.088 ± 0.011 nmol/ml), cardiac risk index (trained 1.96 ± 0.19, untrained 5.88 ± 0.33) and testosterone cholesterol ratio (TCR) (trained 0.40 ± 0.02, untrained 0.50 ± 0.04 × 10−2 ) in trained-participants compared to untrained-participants. Post-exercise level of superoxide dismutase (before-trained, 0.116 ± 0.005 after-trained, 0.093 ± 0.014 mg/ml) and MDA (before exercise 0.067 ± 0.007, after exercise 0.062 ± 0.012 nmol/ml) were also significantly reduced in trained-participants compared with the pre-exercise level in the same group unlike what was obtained in untrained-participants. A significant decreased pre-exercise test level of total cholesterol (TC), triglyceride, low density lipoprotein (LDL) and ratio of LDL to high density lipoprotein (HDL) was recorded in trained compared to untrained-participants. Post-exercise test level of LDL, TC/HDL, LDL/HDL ratios were all significantly lowered in trained-participants compared with the untrained-participants. Conclusion: Involvement of young female adults in exercise training promotes body antioxidant response system and also reduced the TCR during treadmill exercise test compared to untrained young female adults living a sedentary lifestyle. Prior involvement in exercise training also promoted healthy blood lipid and lipoprotein profile in this group of participants compared to the untrained-participants.
Keywords: Cortisol, exercise training, free radicals, oxidative stress, plasma testosterone, treadmill exercise test
|How to cite this article:|
Olubajo AF, Ayinla OO, Margaret A, Adefunke AO. Changes in stress index, blood antioxidants and lipid profile between trained and untrained young female adults during treadmill exercise test: A comparative study. Niger J Exp Clin Biosci 2015;3:1-7
|How to cite this URL:|
Olubajo AF, Ayinla OO, Margaret A, Adefunke AO. Changes in stress index, blood antioxidants and lipid profile between trained and untrained young female adults during treadmill exercise test: A comparative study. Niger J Exp Clin Biosci [serial online] 2015 [cited 2017 May 24];3:1-7. Available from: http://www.njecbonline.org/text.asp?2015/3/1/1/158139
| Introduction|| |
A sedentary lifestyle coupled with a high-calorie intake will lead to poor physical fitness, which will engender cardiovascular system related diseases. Exercise is a healthy habit that needs to be cultivated by both young and old as it helps in body energy balance. Several beneficial effects of regular exercise have been reported. Exercise helps the circulatory system by increasing blood flow through increased venous return and opening up of partially occluded vessels.  Regular exercise will reduce arterial blood pressure by lowering the vascular resistance.  Regular exercise with a cut in calorie intake is an established way of losing weight in obese individuals.  Exercise was reported to improve the recovery of stroke patients in gaining an improved cardiovascular fitness, walking balance and walking functions. , Aerobic exercise attenuates the inflammatory activities associated with systemic lupus erythematosus in women.  Exercise has antioxidant and anti-inflammatory effects in diabetic patients. ,,, Regular exercise training in young healthy men helps in regulating blood lipids, blood pressure as well as oxidative stress.  However, exhaustive exercise as a form of stressor has the ability to create redox homeostatic imbalance , and also stimulates a reduction in body immunity. ,
The reproductive system in a pubertal female undergoes a cyclic pattern that entirely depends on the hormonal influences from the hypothalamo-pituitary-ovarian (HPO) axis. The HPO influences the body functions via the releasing and inhibitory hormones secreted from the pituitary and the hypothalamus. It, therefore dictates the responses expected in a pubertal female to any stressor or metabolic changes experienced. Although, previous authors have explained that there is a better protection against oxidative stress in individuals involved in regular exercise compared with those on a sedentary lifestyle, , reported responses in female participants were with greater impact. , The difference was explained as being partly due to antioxidant potentials exhibited by higher concentration of blood estrogen in female participants. , Having regular physical exercises will mediate against oxidative stress by maintaining body antioxidant enzyme efficiency in menopausal women.  Exercise training in middle-aged women,  young female students  were reported to enhance body handling of increase oxidative stress compared to counterpart on sedentary lifestyle. This study has attempted to quantify the changes in blood reactive oxygen species, plasma cortisol and testosterone in addition to changes in blood pressure, plasma lipid profile and blood glucose in healthy trained female participants and untrained (sedentary) healthy female participants during a 20 minutes programmed treadmill exercise test.
| Materials and Methods|| |
The participants were chosen from among the population after meeting predetermined inclusion criteria as stipulated in the questionnaire administered after the purpose of the study have been well-explained. The sedentary life style participants were chosen among the female students population on campus who barely walk up to 120 m to and from their hostel to lecture halls daily. The exercise trained-participants were selected among the female football players. Only those that have been involved in active sporting activities for over 2 years were recruited as trained-participants. All the participants medical history were carefully taken to ensure none had any history of diabetes, hypertension, or any other ill-health condition that could interfere with the results of this study. All participants included in this study were nonsmokers and were neither on prescribed drugs or locally made concoctions. Although, all participants are normal menstruating women, none was in the menstrual period during the time of the study. At the end of the selection process, 22 young healthy female participants, (12 trained and 10 untrained, age 18.75 ± 1.15 years, height 1.74 ± 0.02 m and body weight 55.25 ± 1.45 kg) took part in this study.
The research procedures adopted and used in this study were approved by the Health Research Committee of Lagos University Teaching Hospital (ADM/DCST/HREC/VOL.XVI/APP/404) and are in accordance with the international standards in medical research and Helsinki declaration of 1975 as revised in 2008.  Informed consent form was filled and signed by all participants after adequately being informed about the purpose and procedures involved in this study. The participants were instructed to fast for 12 h prior to the time of the experiment and data from only those that complied were included in the results analyzed. On the day of the experiment, participants basal data were taken; heights were measured using a standard meter rule, body weights were measured with a weight balance, and waist and hip circumferences were measured with a standardized tape rule. Standardized OMRON automated blood pressure machine (OMRON M2 Basic (HEM-7116-E8(V)), OMRON Healthcare Co., Ltd. Kyoto, Japan) was used to measure the systolic, diastolic and pulse pressure (PP) of all participants, and the mean arterial blood pressures (MABP) were calculated. A volume of 5 ml of venous blood samples was collected from the antecubital vein with the aid of a disposable 5 ml syringe into heparinized sample bottles and used for the determination of blood glucose, lipid profile and antioxidant status. The lipid profile (total cholesterol [TC], triglyceride [TG], high density lipoprotein [HDL], low density lipoprotein [LDL]) was measured with an automated cardio-check analyzer (CardioChek P-A Polymer Technology Systems, Inc., Indianapolis, IN, USA) using 1-2 drops of the whole blood sample from each participant. The following derived lipid profile parameters were also calculated; cardiovascular risk indicator (CRI) and LDL-HDL ratio. The whole blood glucose level was measured with the aid of a precalibrated glucometer (ACCU-CHEK Active (Model GC, Roche Diagnostics Gmbh, 68298 Mannheim, Germany)) using 1-2 drops of the blood sample. The remaining blood samples were centrifuged at 3000 rpm for 10 min (25°C) to obtain the plasma.
Each participant was taken through an initial 3 minutes warm up exercise on the treadmill at a speed of 0.5 km/h at normal room temperature before the commencement of the treadmill exercise test. After the warm up exercise, the participants were immediately taken through a single bout of the exercise section at a speed that was gradually increased from 0.5 km/h to 1.5 km/h within 2 minutes and lasting for 20 min. Immediately after the 20 minutes treadmill exercise test, each participant's blood pressure parameters were measured as previously described. 5 ml of the blood sample was collected again using the method described earlier and the samples used for measurement of blood glucose, lipid profile and antioxidant status. Testosterone concentration, cortisol level and oxidative stress parameters (catalase [CAT], glutathione [GSH], malondialdehyde [MDA], and superoxide dismutase [SOD]) were assayed from the plasma. The hormones; testosterone and cortisol were analyzed using enzyme linked immunosorbent assay kit (ELISA, Diagnostics Biochem. Canada Inc.) according to manufacturer protocols. The principle of this assay is competitive binding of antigen and enzyme-linked antigen onto a limited number of antibody sites in a microplate (solid phase).
Cortisol ratio testosterone cholesterol ratio (TCR) was calculated from the results of testosterone and cortisol values. CAT was analyzed using calorimeter at 620 nm according to the method of Sinha  while GSH was determined by the method of van Doorn et al. MDA was estimated using the method of Mihara and Uchiyama.  SOD enzyme was determined according to the method described by Sun and Zigman.  CAT activity was determined by measuring the exponential disappearance of H 2 O 2 at 240 nm and expressed in U/mg of protein as described by Aebi. 
Data were analyzed using SPSS statistics version 17.0 for window (SPSS Inc. 233, Chicago, IL 60606-6412, USA). Descriptive statistics of the mean ± standard error of the mean was used for socio-demographic characteristics. Results were displayed in the form of tables and bar charts. The significance of the difference of the difference between pretest and posttest mean score was analyzed using two-way ANOVA. Level of significance was placed at P ≤ 0.05.
| Results|| |
Anthropometry results of all participants in the two groups showed no significant difference in the body weight, height, body mass index (BMI), hip circumference and waist line. Significant difference was, however, recorded in the age of the participants where the ages of those participants in trained group were significantly lower (P ≤ 0.05) compared with those in the untrained group [Table 1].
|Table 1: Anthropometry of trained and untrained young female participants involved in this study|
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Plasma Testosterone and Cortisol Level
Plasma testosterone and cortisol level before the treadmill exercise test were not significantly different between the two groups. However, the post-treadmill exercise test plasma testosterone level was significantly increased (P ≤ 0.05) in untrained-participants compared with the pre-treadmill exercise test level. The pre-exercise TCR value in trained-participant was significantly higher than in untrained-participant. Post-exercise TCR value in trained-participants was significantly lower than the pre-exercise while the reverse was the case recorded in untrained-participants. However, there were no significant changes in cortisol level between and within the two groups before and after the treadmill exercise test [Table 2].
|Table 2: Plasma testosterone and cortisol level in exercise trained and untrained young female participants pre- and post- treadmill exercise test|
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Lipid Profile and Blood Glucose Changes
Basal TC, TG LDL, TC/HDL and LDL/HDL ratio were significantly lower in trained-participants compared with untrained-participants. Post-exercise level of LDL, CRI and LDL/HDL ratio were significantly lower in trained compared with the values in untrained-participants. Post-treadmill exercise test ratio of TC/HDL in trained-participants was significantly decreased (P ≤ 0.05) compared with pre-exercise level in untrained-participants [Table 3]. The results of the LDL/HDL ratio were significantly decreased in trained-participants compared with the level in untrained-participants both before and after the treadmill exercise test.
|Table 3: Lipid profile and BG results in trained and untrained young female participants pre- and post-treadmill exercise test|
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The pre and post-treadmill exercise test level of systolic blood pressure (SBP), diastolic blood pressure (DBP), MABP were not significantly different between trained and untrained-participants. However, both post-exercise results of SBP and DBP in both trained and untrained-participants were significantly increased when compared with the corresponding pre-treadmill exercise test results. The pre-treadmill exercise test level of PP was significantly higher (P ≤ 0.05) while heart rate (HR) was significantly lower in trained-participants compared with untrained-participants. Only post-treadmill exercise test level of HR recorded a significant increase when compared with the corresponding post-exercise level in untrained-participants out of the entire blood pressure parameters measured [Table 4].
|Table 4: Pre- and post-treadmill exercise test cardiovascular parameters results of trained and untrained young female participants|
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Oxidative Stress Results
The pre-exercise level of SOD was significantly higher (P ≤ 0.05) while CAT level was significantly lower in trained-participants compared with the levels in the untrained-participants. Post-exercise level of GSH, CAT, and MDA was significantly lower in trained-participants compared with the levels in untrained-participants. Post-exercise level of GSH and SOD were significantly lower than the pre-exercise level in all trained-participants. Post-exercise level of SOD and MDA were significantly higher (P ≤ 0.05) than the pre-exercise level in untrained-participants [Table 5].
|Table 5: Results of oxidative stress parameters in trained and untrained young female adult pre- and post-treadmill exercise test|
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| Discussion|| |
Exercise of various intensities and durations has enough potential to provoke increased generation of free radicals in the body.  However, how the body handles the resulting oxidative stress condition has been the interest of many scientific researches. Inability of the body to strike a balance between generation and mopping up of these free radicals will result in various degrees of metabolic and degenerative complications in the body system. This study tried to evaluate how the body of a healthy young female adult maintains oxidative stress homeostasis during a treadmill exercise test. We also tried to compare the responses between trained and untrained-participants. The ages of the girls recruited for this study range from 15 to 21 years. We notice that the age of the trained-participants was significantly lower compared to the untrained-participants. These we partly attributed to the observation that older girls drop out of spotting activities to settle down as married women or carrier women. All other parameters measured including body weight, height, BMI, hip circumference and waist circumference were not significantly different between the two groups.
In this study, post-exercise test SOD and MDA levels were significantly increased in untrained-participants, while the trained-participants recorded a significant reduction in the plasma level of GSH and SOD compared with pre-exercise levels. The plasma SOD level in trained-participants before the exercise test was, however, significantly higher compared with untrained-participants. Involvement in regular exercise training significantly reduces the generation of free radicals with a significant reduction in the plasma GSH and SOD in the trained-participants. These results corroborate previous reports that regular exercise training offers a protective effect against excessive generation of free radicals in the body.  Our results showed no significant change in the plasma level of MDA in the trained-participants corroborating previous reports of Andersson et al.,  study in elite female athletes. However, we recorded a significant increase in lipid peroxidation in the untrained-participants as indicated by the increased plasma MDA level after the treadmill exercise test [Table 5]. Studies carried out in middle age women with age range of 45-51 years recorded similar changes in MDA results between exercising and nonexercising participants. 
The results of the cardiovascular parameters measured revealed no significant difference in pre and post-treadmill exercise test SBP, DBP and MABP between trained and untrained female participants [Table 4]. However, pre and post-treadmill exercise test HR in trained-participants was significantly lower, while pre-treadmill exercise test PP was significantly higher when compared with corresponding values in the untrained-participants. Some authors have attributed this phenomenon to reduction in intrinsic adaption in the sinus node, , while others have explained it as the result of the increase in the parasympathetic activity. 
Trained-participants have a significantly higher basal level of testosterone compared with the untrained-participants. There are conflicting reports about changes in testosterone level in female when involved in exercise training. Some authors reported no significant change,  a significant reduction,  and a significant increase.  Our results showed a significant increase in testosterone after the exercise test in untrained-participants while the level remained relatively unchanged in trained-participants [Table 2]. However, TCR was significantly lowered in the trained-participants after the treadmill exercise test when compared with their pre-exercise values as well as when compared with the untrained-participants whose TCR were significantly increased after the treadmill exercise test. The ratio of testosterone to cortisol level gives the stress index (SI) or the anabolic/catabolic index in the body. , This SI is also a measure of body adaptation. A decrease in TCR indicates a state of increased anabolism engendered by either an increased testosterone level or a decrease in the level of the catabolic hormone; cortisol. In addition, inter-group TCR analysis shows a significant increase in TCR in trained-participants before the treadmill exercise test compared with the untrained-participants while the reverse was recorded after exercise test. The increased TCR recorded in untrained-participants after the exercise test was due to the significant increase in testosterone level when compared with the basal level. The recorded TCR results in this study buttressed the theory that the exercise confers an adaptation mechanism on the body that helps in reducing stress. 
Analysis of the pre-exercise plasma lipid profile of trained female participants revealed a significant decrease in the plasma level of TC, TG, LDL, LDL/HDL and TC/HDL compared with untrained female participants that are living a sedentary lifestyle. Thus, their involvement in exercise training for a period that was not <2 years has an overall effect of improving the blood lipid and lipoprotein profile due to the significant decrease in the LDL/HDL and TC/HDL ratio.  This recorded decrease in TC/HDL ratio in the trained female participants prior to the commencement of treadmill exercise test correlates to the regular exercise training and have been reported by other authors who have worked with middle-aged women (45-55 years)  and elderly women (60-65 years).  The age of female participants that participated in this study is of importance due to the age-associated changes in body hormones and metabolism during puberty and menopause. Other authors who have reported no significant change in the TC/HDL ratio after prolonged exercise training have used female participants with age range 10-18 years or lower. , While a significant reduction in the plasma level of LDL, LDL/HDL and TC/HDL was recorded after the programmed exercise in trained-participants, HDL level was significantly increased compared to the untrained group. Several researchers have reported the beneficial effects of exercise training on modification of lipid profile in favor of increased HDL and reduced LDL. , There was no significant change in the blood glucose during the exercise period within and between the groups contrary to what was reported earlier in male participants that undergo similar treadmill exercise test. 
| Conclusion|| |
Young female adults that are exposed to exercise training over a long period showed enhanced protection against oxidative stress as shown by the significant reduction in plasma level of CAT, GSH and MDA, and a reduction in the SI during treadmill exercise test compared with the untrained young female participants living a sedentary lifestyle. They also recorded healthy basal blood lipid and lipoprotein profile compared to the untrained counterpart.
| Acknowledgments|| |
The authors would like to thank the head of Department of Physiotherapy, Faculty of Clinical Sciences, College of Medicine, University of Lagos for the permission to carry out this study at their physiotherapy exercise clinic. We would also like to thank the technical assistance of the technologists at the clinic.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]