C:\Users\JURNAL FKUSAKTI\Docume 166 *Department of Medical Laboratory Science, Faculty of Health Sciences and Technology, Nnamdi Azikiwe University, Nnewi Campus, Anambra State Nigeria **Department of Chemical Pathology, Faculty of Medicine, Nnamdi Azikiwe University, Nnewi Campus, Anambra State Nigeria ***Education Department, Medical Laboratory Science Council of Nigeria †Department of Biochemistry, Faculty of Biological Sciences, Anambra State University, Owerri, Nigeria ††Department of Human Biochemistry, Faculty of Basic Medical Sciences, Nnamdi Azikiwe University, Nnewi Campus, Nigeria Cor r espo nde nc e Augustine Chinedu Ihim Department of Medical Laboratory Science, Faculty of Health Sciences and Technology, College of Health Sciences, Nnamdi Azikiwe University, Nnewi Campus, P.M.B. 5001, Anambra State, Nigeria Email: ac.ihim@unizik.edu.ng Date of first submission, September 18, 2 01 7 Date of final revised submission, October 31, 2017 Date of acceptance, November 1, 2017 This open access article is distributed under a Creative Commons Attribution- Non Commercial-Share Alike 4.0 International License ABSTRACT UNIVERSA MEDICINASeptember-December, 2017 Vol.36 - No.3 Short-term aerobic exercise does not change kidney function in students of Nnamdi Azikiwe University, Nigeria Ihim Augustine Chinedu*, Patrick Chinedu Obi**, Egbe Josephat Udoka*, Nosakhare Osakue*, Donatus F. Ozuruoke***, Emmanuel I. Nwobodo†, Samuel C. Meludu††, and Okeke Chizoba Okechukwu* BACKGROUND Exercise has been known to have beneficial effects on human health. The kidneys play an important role in regulating acid-base and water-electrolyte balance disturbances induced by exercise. The objective of this study was to investigate the effect of short-term aerobic exercise (volleyball training) on the kidney function of apparently healthy individuals. METHODS An experimental study of pre-post test design was conducted involving 41 amateur volleyball players, comprising 22 males and 19 females. They were randomly divided into seven different teams. Each team trained for at least 45 minutes for four consecutive days for two weeks. Both pre-and post- exercise blood pressure (BP) was measured using an automatic blood pressure measuring device OMRON 907 (OMRON, Hoofddorp, Netherlands). Likewise, both pre- and post-exercise blood samples were collected into lithium heparin tubes and centrifuged at 3000 rpm for 10 minutes and the plasma separated into plain tubes. Electrolytes were analysed using ion selective electrode machine (SFRI 4000, Germany), urea using modified Berthelot method, creatinine using Jaffe-Slot method and uric acid using the uricase method and estimated glomerular filtration state (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) formula. RESULTS The mean levels of pre- and post-exercise systolic blood pressure, creatinine, urea, sodium, potassium, chloride, bicarbonate and eGFR did not differ significantly (p>0.05). However, serum uric acid was significantly increased (p<0.05), while diastolic BP significantly decreased after exercise (p<0.05). CONCLUSION The study showed that short-term moderate intensity aerobic exercise does not have any significant effect on the renal functions. Keywords: Short-term, aerobic exercise, kidney function, students DOI: http://dx.doi.org/10.18051/UnivMed.2017.v36.166-172 ORIGINAL ARTICLE pISSN: 1907-3062 / eISSN: 2407-2230 Cite this article as: Chinedu IA, Obi PC, Udoka EJ, et al. Short term aerobic exerci se d oes not cha nge kidn ey function in students of Nnamdi Azikiwe University, Nigeria. Univ Med 2017;36: 166-72. doi: 10.18051/UnivMed.2017. v36.166-172 167 Univ Med Vol. 36 No.3 INTRODUCTION Several studies have reported that exercise is associated with both long-term and short-term metabolic, physiological and hemodynamic changes which can impact either positively or negatively on the health of the exercising subjects. Physical activity has been shown to h a ve a p osi t ive e f f e c t o n man y c h r on i c conditions such as cardiovascular disease, chronic kidney disease and diabetes.(1) The benefits of physical activity to renal health have been demonstrated in a few studies but there are still questions which remain unanswered. One of the unanswered questions is related to the longitudinal effects of physical activity on renal function. The few studies which have sought to address this question in humans have revealed conflicting results.(2,3) A study investigated the association between physical a c t i vit y, me a su r e d ob j e c t i vel y wi t h a n accelerometer, and kidney function, and showed that total and light physical activities were found t o b e po s it i ve l y a s so c i a t e d wi t h ki d ne y function.(4) However another study in middle-aged women showed that six months of aerobic training does not induce significant change in estimated glomerular filtration rate and blood urea nitrogen.(5) Students in the environment of Anambra state, Nigeria, are daily involved in physical activities, some of which have become part of their lifestyle (e.g long distance walking, climbing staircases, climbing down and up the hilly environment of the school etc) and some others as recreational activities (volleyball, badminton, soccer and jogging). Specifically, volleyball playing is becoming an interesting sport of choice for students in this community. However, no study has been done with regard to its effect on the kidney function in the e nvi ro n me n t o f A na mb ra st a te , N i ge r ia . Therefore, this study is designed to assess the a c u t e o r sh or t-te r m e f f e c t s of e x e r c i s e (volleyball practice) on the kidney function of apparently healthy students of Nnamdi Azikiwe University, Nigeria. METHODS Research design This was an experimental pre-post test designed to assess the effect of short term exercise on the kidney function and was conducted from July to September 2016. Study area The study was carried out in the College of Health Sciences, Nnamdi Azikiwe University, Nnewi, Anambra state, Nigeria. This is a multi- faculty college comprising the Faculties of Health Sciences and Technology, Medicine and Basic Medical Sciences. Each of these Faculties is made up of numerous departments such as Medical Laboratory Science, Anatomy, Nursing, Medical Rehabilitation, Medical Radiography, Physiology, Medical Biochemistry, Pharmacology, Community Medicine etc. It has sporting facilities including a football field, volleyball court, tennis court etc. Study subjects The study participants were students of the College of Health Sciences, Nnamdi Azikiwe University Nnewi, Anambra State. A total of forty-one (41) student amateur volleyball players comprising 22 males and 19 females who volunteered to participate in the study, were recruited for this study. The inclusion criteria were apparently healthy students within the age range of 17–28 years, who play volleyball and were willing to participate in the study. The following subjects were excluded; those suffering from any renal disease or hypertension, those who sustained any form of musculoskeletal injury, alcoholics, smokers and those on any form of medication including herbal remedies. Sampling was done by stratified sampling technique, where students were grouped into strata according to their departments. Students 168 were selected from each department of the faculty using simple random sampling. Exercise potocol T he s ub j e c ts wer e i nstr uc t ed n ot t o participate in any form of sports for one-week. After the one week of rest, the subjects were randomly divided into six (6) teams comprising 6 participants each, while the seventh team was comprised of 5 participants. Each team was subjected to volleyball training for a minimum time of 45 mins for four consecutive days in one- week for two-week periods. Measurements Anthropometric parameters such as the h e igh t an d we ight of e a ch s ub j e c t we r e measured using a standard stadiometer and a weighing scale before the exercise session and their body mass index (BMI) were calculated from it. Subjects’ dietary pattern and lifestyle were also obtained using a well-structured questionnaire. A pre-exercise blood pressure was measured by taking two blood pressure (BP) readings on the right arm placed at the heart level, using an automatic blood pressure measuring device OMRON 907 (OMRON, Hoofddorp, Netherlands) after the subjects had rested for at least 5 minutes in a sitting position upon arrival to the volleyball court. T he measurements were taken 60 seconds apart and the average systolic and diastolic BP were recorded and used for data analyses. Post- exercise BP were also taken after exercise on the last day. Laboratory analysis Five mL each of pre-exercise and post- exercise blood samples was drawn from the ante-cubital vein of each of the participants before the commencement of the exercises. The blood samples were collected into lithium heparin anticoagulant containers before commencement of the exercise session and on the last day of the session after exercise. The blood sample was then centrifuged at 3000 rpm for 5 minutes and then the plasma was extracted and kept frozen until biochemical analyses were carried out. Urea estimation was carried out using the modified urease-Berthelot methods.(6) The Jaffe- Slot method was us ed to estimate the concentration of creatinine.(7) Estimation of uric acid was determined by the uricase based methods.(8) The electrolytes assayed include sodium (Na +), potassium (K +), chloride (Cl-) and bicarbonate (HCO3) and this was done using Ion Selective Electrode (ISE). The estimated glomerular filtration rate (eGFR) was calculated using an online calculator for the Modification of Diet in Renal Disease (MDRD) formula for adults.(9) The formula is given as: GFR (ml/min /1.73m2) = 186 x [plasma creatinine (µmol/L)]-1.154 x [age]-0.203 x [1.210 (if black)] x [0.742 (if female)]. Statistical analysis Statistical package for Social Science Students (SPSS) version 16.0 was used for the analysis of the results. Data were presented as mean ± standard deviation (SD) and Student’s paired t-test and independent t-test were used to determine level of significance set at p<0.05. Ethical consideration Ethical approval was sought and obtained from the ethics committee of the Faculty of Health Sciences, Nnamdi Azikiwe University (No 2011614024P). An informed consent of all participants was obtained before they were recruited for the study. RESULTS T he r e su l t s o f a n t hr op ome t r i c measurements of the participants showed that there was no statistically significant difference in the mean values of the male and female participants’ age (23.23 ± 2.30 years; 21.74 ± 1.33 years), height (1.76 ± 0.05 m; 1.67 ± 0.06 m) and BMI (23.05 ± 1.68 kg/m2; 22.39 ± 3.22 Chinedu, Obi, Udoka, et al Short term aerobic exercise and kidney function 169 Univ Med Vol. 36 No.3 A B C kg/m2), respectively (p>0.05) except in their weight (71.23 ± 7.19 kg; 62.37 ± 10.04 kg) (p<0.05) (Table 1). As shown in Table 2, their diastolic BP was significantly lower after exercise (p=0.021). However, the pre and post exercise systolic BP showed no significant difference (p=0.087). T he p o st e xe r c i se ur i c ac i d me a n concentration was higher than the pre-exercise va lue (p=0.011 ). However, there was no significant difference in the mean values of electrolytes, urea and creatinine (p>0.05). There was also no significant difference in the mean values of the participants’ GFR before and after exercise (p=0.548) (Table 2). DISCUSSION Several reports have shown that duration and/or intensity of exercise elicit different effects on minerals metabolism and that inadequate status of the body mineral composition can lead to a diminution of performance and endurance both in sportsmen and rats.(10,11) Longer duration of exercise is needed to elicit a significant decrease in some biochemical parameters. (12) During aerobic exercise, systolic BP increases, since as the exercise intensity increases the heart works harder to pump more oxygenated blood to the muscles. At the same time, diastolic BP remains relatively stable and may even decrease slightly. On average, men have higher BP than women during aerobic exercise.(13) Such changes could have transient effects on the GFR as well as the renal function. The findings from this work revealed that during short-term volleyball exercise, diastolic pressure decreased significantly. This drop in the diastolic pressure can be attributed primarily to the vasodilation of the arteries from the exercise bout which causes a reduction in peripheral resistance. It could also be due to a decrease i n the blood volume caused by dehydration from water loss after exercise. This finding is in consonance with the findings of Syme et al.(14) who conducted a study and showed a decrease in diastolic blood pressure post exercise. However, there was also a small Parameter Male (n=22) Female (n=19) p value Age (years) 23.23 ± 2.30 21.74 ± 1.33 0.087 Weight (kg) 71.23 ± 7.19 62.37 ± 10.04 0.021* Height (m) 1.76 ± 0.05 1.67 ± 0.06 0.611 BMI (kg/m2) 23.05 ±1.68 22.39 ± 3.22 0.624 Table 1. The distribution of mean values of anthropometric measurements in the subjects BMI : body mass index; Significant values set at p<0.05; *Significant Parameters Pre-exercise (n=41) Post-exercise (n=41) p value SBP (mmHg) 112.71 ± 9.00 116.10 ± 12.74 0.087 DBP(mmHg) 79.98 ± 11.61 76.39 ± 8.20 0.021* Na+ (mmol/L) 139.14 ± 2.36 138.41 ± 2.56 0.143 K+ (mmol/L) 3.61 ± 0.30 3.61 ± 0.46 0.991 Cl- (mmol/L) 102.89 ± 6.59 101.44 ± 2.01 0.154 HCO3 - (mmol/L) 21.81 ± 2.58 22.70 ± 2.55 0.078 Urea (mmol/L) 3.60 ± 0.88 3.79 ± 0.83 0.133 Uric acid (mmol/L) 326.47 ± 109.20 380.04 ± 54.58 0.011* Creatinine (µmol/L) 72.36 ± 14.24 73.22 ±18.72 0.717 GFR (ml/min/1.73m2) 135.51 ± 54.96 129.27 ± 27.50 0.548 SBP= systolic blood pressure; DBP= diastolic blood pressure; GFR= glomerular filtration rate; Significant values set at p<0.05. *Significant Table 2. The blood pressure and renal function test of the subjects before and after exercise 170 but insignificant increase in their systolic blood pressure. The mean concentrations of electrolytes after the exercise session as compared to the pre-exercise values, showed no significant change. It was observed that although there was a slight decrease in the mean concentrations of sodium and chloride ions after the volleyball exercise, this decrease was not significant. This slight but insignificant decrease in sodium can be attributed to minute loss of sodium in sweat d ur ing t he e x e rc is e . Al s o t h e s l i ght b u t insignificant reduction in the chloride ion can be explained by the fact that during exercise, reduction in sodium is accompanied by reduction in chloride as both sodium and chloride ions are the main constituents of sweat. It was also found that there was a positive correlation between the pre- and post-exercise concentrations of sodium and chloride. These findings were in agreement with those of Baydil,(15) who reported that the change in the mean concentration of sodium and chloride ions in individuals who exercised to the point of exhaustion were not significant. However, another study showed that e x e r c i s e r e du c e d s o di u m a n d c hl o r i de concentration significantly.(16) During exercise, muscle K+ efflux increases with increasing exercise intensity, and therefore maximal exercise induces a marked elevation in arterial plasma potassium ion.(17) However, the present study revealed that there was no change between the pre-exercise mean concentration of potassium ion and the post-exercise concentration. This can be explained by the fact that the changes in extracellular potassium ion concentrations are initially buffered by movement of potassium into and out of the skeletal muscle, a phenomenon known as internal potassium balance. It may be also have been due to the fact that the exercise was moderate in intensity and lasted for forty-five minutes. This does not support the observations made by several studies (15,18) that reported a significant increase in potassium concentration following exercise. Similarly, the post-exercise bicarbonate concentration changes in this work showed a small but insignificant increase when compared to the pre-exercise value. T his increase can be attributed to the physiological re-absorptive adjustment made by the kidneys in order to buffer the blood pH which tends to acidity as a result of increased CO 2 production from respiration during the exercise session. This observation is in conformity with the findings made by Ugwuja et al.,(19) who reported that exercise caused no significant change in the serum concentrations of bicarbonate. Glomerular filtration is one of the key functions of the kidney and assessing the glomerular filtration rate has important clinical implications. Previous work reported a decrease in GFR after exercise.(20) According to the report, this decrease is dependent on the exercise intensity. This finding can be explained by the fact that during exercise, the renal blood flow tends to reduce as a result of the effect of the sympathetic nervous system and the release of catecholamines which induces the reduction of blood flow to the kidneys, which in turn de cr ea se s th e gl omeru la r fi ltr a tion r at e. However, the work by Ayca et al.(21) revealed that the glomerular filtration rate of individuals performing volleyball exercise decreased slightly but not significantly. This insignificant decrease can be attributed to the moderate intensity and short duration of the exercise and possibly to the use of serum creatinine and MDRS formula in calculating GFR. Furthermore, the present study showed that the mean concentrations of creatinine and u re a be f or e an d af te r e xe rc is e wer e not significantly increased. This can be attributed to the moderate intensity and short duration of the exercise and also to the reduced renal blood perfusion and slight decrease observed in the GFR of the participants after the volleyball exercise. A previous study conducted on half- marathon athletes reported an increase in GFR and creatinine clearance which contradicts the observation made in our study.(22) Chinedu, Obi, Udoka, et al Short term aerobic exercise and kidney function 171 Univ Med Vol. 36 No.3 In the present study a significant increase in the mean concentration of uric acid of the participants was observed. This is in line with the findings of Dunlap et al.(23) The increase can be explained by the fact that during short and long term exercise, the increase in uric acid levels serves as a protective mechanism against exercise induced oxidative stress. It was also observed in the present study that the pre-creatinine concentration correlated positively and significantly with age, height, weight and BMI, whereas no correlation was found between these parameters and the pre- exercise blood urea concentration. This is in accordance with previous studies.(24,25) Meyer e t a l . ( 2 6 ) r e po r t e d t h a t s e r u m c r e a ti n i ne concentration varies closely with the skeletal muscle mass. Also the study showed that the post-exercise concentration of creatinine was correlated negatively and significantly with the post-exercise GFR value, whereas there was no significant correlation between the pre- exercise concentrations. The limitation of this study was that the exercise was a short term plan and could have affected the study results that there was no significant change in the kidney function of the participants. Moreover the intensity of the volley ball training was not considered. A prospective study in this line should endeavour to consider using a larger sample size, engage participants on long term exercise (volley ball) for a month and ensure that training intensity is consistent. CONCLUSION This study found that short-term aerobic exercise (volleyball training) caused slight but insignificant changes in the renal function tests, showing that invariably it caused no renal function impairment. CONFLICT OF INTEREST The authors declare that no conflict of interest exists. ACKNOWLEDGEMENT We appreciate greatly the management of Reene Medical Diagnostic Centre, Awada Obosi, Idemili North LGA, Anambra State for granting us permission to use their laboratory for the biochemical analysis of the samples. CONTRIBUTORS ACI, SMC and NO contributed to draft the ma nu s c r ip t . ACI, S MC, NO a n d DO F contributed to conception and design of the study. EF, ENI and OCO contributed to acquisition of the data. SMC, ACI and PCO contributed to data analysis and interpretation. ACI, EJ, RNI, OCO and SMC contributed to revising the manuscript critically for important intellectual content. All authors read and approved the final manuscript. REFERENCES 1. Cigolle CT, Blaum CS, Halter JB. Diabetes and cardiovascular disease prevention in older adults. Clin Ger Med 2009;25:607-41. 2. White SL. Physical inactivity and chronic kidney disease in Australian adults: The Aus Diab study. Nutr Metab Cardiovascular Dis 2009;12:125-30. 3. Robinson-Cohen C. Physical activity and rapid decline in kidney function among older adults. Arch Int Med 2009;169:2116-23. 4. Hawkins MS, Sevick MA, Richardson CR, et al. Association between physical activity and kidney function: National Health and Nutrition Examination Survey. Med Sci Sports Exerc 2011;43:1457-64. 5. Bijeh N, Farahati S. The effect of six months of aerobic training on renal function markers in untrained middle-aged women. Intl J Sport Stud 2013;3:218-24. 6. Pandya D, Nagrajappa AK, Ravi KS. Assessment and correlation of urea and creatinine levels in saliva and serum of patients with chronic kidney disease, diabetes and hypertension: a research study. J Clin Diagn Res 2016;10:ZC58-6. 7. Kakkar M, Kakkar R. A comparative study on the estimation of serum creatinine levels by Jaffe’s and enzymatic methods at different levels of serum bilirubin. Int J Clin Biochem Res 2017;4:305-30. doi: 10.18231/2394-6377.2017.0071. 172 8. Zhao Y, Yang X, Lu W, et al. Uricase based methods for determination of uric acid in serum. Microchim Acta 2009;164:1–6. doi: 10.1007/s00604 -008-0044-z. 9. Levey AS, Bosch JP, Lewis JB, et al. Modification of diet in renal disease study group: a more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Ann Intern Med 1999;130:461-70. 10. Nielsen FH, Lukaski HC. Update on the relationship between magnesium and exercise. Magnes Res 2006;19:180-9. 11. Rakhra G, Masih D, Vats A, et al. Copper, iron, zinc and magnesium status of physically active young Indian males. J Sports Phys Educ 2015;2: 25-32. 12. Ihim AC, Meludu SC, Obiodinukwe CM, et al. Effect of short-term exercise on serum cortisol and lipid profile in young male of College of Health Sciences, Nnamdi Azikiwe University, Nnewi Campus. Indian J Basic Ap Med Res 2015;4:213- 8. 13. Brooks GA, Fahey TD, Baldwin KM, editors. Human bioenergetics and its applications. In: Exercise physiology. 4th Ed. Mc Graw Hill; New York;2005.p.122-5. 14. Syme AN, Blanchard BE, Guidry MA, et al. Peak systolic blood pressure on a graded maximal exercise test and the blood pressure response to an acute bout of submaximal exercise. Am J Cardiol 2006;98:938-43. 15. Baydil B. Serum macro-micro element response to acute maximal physical exercise. World Appl Sci J 2013;2:945-9. 16. Anastasiou CA, Kavouras SA, Arnaoutis G, et al. Sodium replacement and plasma sodium drop during exercise in the heat when fluid intake matches fluid loss. J Athletic Train 2009;44:117- 23. 17. Harmer AR, Patricia AR, Michael J, et al. Effects of sprint training on extrarenal potassium regulation with intense exercise in type 1 diabetes. J Appl Physiol 2006;100:26-34. 18. Cinar V, Baltaci AK, Mogulkoc R. Effect of exhausting exercise and calcium supplementation on potassium, magnesium, copper, zinc and calcium levels in athletes. Pak J Med Sci 2009;25: 238-42. 19. Ugwuja SE, Obeagu EI, Ochei KC, et al. Effect of physical exercises on serum electrolyte. J Dent Med Sci 2014;13:118-21. 20. Morales AP, Sampaio-Jorge F, da Cruz Rangel LF, et al. Cardiopulmonary performance during maximal exercise in soccer players with alterations in renal function. J Hum Kinet 2017;57:107-15. doi: 10.1515/hukin-2017-0052. 21. Ayca B, Sener A, Apikogl-Rabus S, et al. The effect of exercise on urinary gamma-glutamyl transferase and protein levels of volley ball players. J Sports Med Phys Fitness 2006;46:623-7. 22. Lippi G, Schena F, Salvagno GL. Acute variation of estimated glomerular filtration rate following a half-marathon run. Int J Sports Med 2008;29:948- 51. doi: 10.1055/s-2008-1038745. 23. Dunlap KE, Reynolds AJ, Duffy LK. Total antioxidant power in sled dogs supplemented with blueberries and the comparison of blood parameters associated with exercise. Comp Biochem Physiol A Mol Integr Physiol 2006;143: 429-34. 24. Traynor J, Mactier R, Geddes CC, et al. How to measure renal function in clinical practice. BMJ 2006;333: 733-737. 25. Lamb EJ, Tomson CR, Roderick PJ. Estimating kidney function in adults using formulae. Ann Clin Biochem 2005;42:321-45. 26. Myers GL, Miller WG, Coresh J. Recommendations for improving serum creatinine measurement: a report from the Laboratory Working Group of the National Kidney Disease Education Program. Clin Chem 2006;52:5-18. Chinedu, Obi, Udoka, et al Short term aerobic exercise and kidney function