@2024 Afarand., IRAN

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ISSN: 2252-0805    The Horizon of Medical Sciences 2015;21(3):181-188

Background
… [1-9] CRP is known as a main and independent marker of cardiovascular complications [10]. CPR level in adults has a direct correlation with age, smoking, lipid level, chronic inflammation and fat content [9]. … [11-13] Epidemiological studies have been detected a correlation between physical exercises and anti-inflammatory effects [14]. … [15, 16]
Previous Studies
Several studies have been carried out in terms of the effect of endurance and resistance exercises on circulating level of interleukin-18 and CRP [17-20], but the results are not consistent. Less research has been done on the effect of exercise training on serum levels of interleukin-18 [19, 21], and their findings are not consistent with each other. … [22, 23] There are some doubts about the correlation between interleukin-18 and CRP on the one hand and exercise and body mass index on the other hand [9, 20-22, 24, 25]. … [26-28]
Aim(s)
The aim of this study was to determine the response of circulating levels of interleukin-18 and C-reactive protein with high sensitivity to endurance and resistance exercise in inactive lean men.
Research type
This is a quasi-experimental research including control and experimental groups with pretest and posttest.
Research society, place and time
Inactive lean men in Bukan and Saqqez cities (Iran) were studied in 2011.
Sampling method and number
28 males were chosen based on purposive sampling.
Used devices&materials
Those with BMI less than 18.5 kg/m2 and who did not have a history of regular physical activities in the year before the study, were entered the study. Volunteers who had the history of cardiovascular diseases, diabetes, thyroid disease, and any pathological condition or took any medication (with or without prescription), or were under any kind of diet or another therapy were excluded from the study. Any drug addiction, smoking, and alcohol and caffeine consumption led to exclusion of volunteers from the study. The number of participants was 9 in endurance exercise group, 9 in resistance exercise group, and 10 in the control group. 1RM was determined individually and separately for each muscle group through the following formula [29]: 1 rep max=(Weight Lifted)/(1.0278-(0.0278*numer of reps) … [30, 31] The endurance exercise protocol included 12 weeks of pedaling on an ergometer bicycle. The exercise was carried out three sessions a week, every other day. Severity of exercise was 60 to 70% of heart rate reserved of each individual. Duration of training was 20 minutes at the beginning of the period that gradually increased to 40 minutes until the end of period (20-minute exercise with severity 60% of heart rate reserved at the first four weeks, 30-minute exercise with severity 65% of heart rate reserve at the second four week, and 40-minute exercise with severity 70% of heart rate reserved at the third four weeks). Protocol of resistance training was 12 weeks of weight training. The exercise was carried out three sessions a week, every other day. Weight training duration was about 60 minutes per session. Weight training included 10 stations (biceps with a barbell, triceps with a barbell, Dumbbell shoulder exercise, underarm with dumbbells, bench press with a barbell, sit-up, leg press, squats Hawke , bending the knee, and opening the knee) which carried out three times in each station with 8- to 12-repetition and the intensity 60-80% 1RM. The participants in the exercise groups were asked to avoid performing any extra physical activity. Participants had to avoid eating caffeine, smoking, taking any medication, and doing any type of physical activity three days before sampling, and refrain from any eating and drinking 12 hours before sampling. Participants` weight was measured using a digital hygrometer with minimal precision 0.1 kg (ws 80; Switzerland), and their height was measured using a stadiometer with a minimum accuracy 0.1 cm (Machinen AG, Switzerland). Body Mass Index was calculated by dividing weight (in kilograms) by the square of height (in square meter). Body density was figured out by measuring the subcutaneous fat in the three body points (chest, triceps and sub-scapular) by caliper with a minimum accuracy 1mm (Harpenden, England) using Jackson & Pollock equation [32]. Then, the percentage of body fat was calculated using Siri equation [33]. The estimation of maximum heart rate (Age-220) and heart rate reserve (resting heart rate-maximum heart rate) was performed using a digital wrist sphygmomanometer model Ms-906 (Fresh life, Taiwan). Endurance exercise was performed on a stationary magnetic Robimax bicycle ergometer (ROBIMAX 7750, Taiwan), and VO2 max (maximal oxygen consumption) was estimated using Submaximal Astrand-Rhyming cycle test. Standard diet contained consumption of 15% protein, 30% fat, and 55% carbohydrate. In order to estimate the basal metabolic rate of participants, Harris-Benedict equation was used with activity level of 1.55 for experimental group and 1.1 for control group [31]. HsCRP serum concentration was measured with High Sensitivity CRP (hs-CRP) kit with intra-essay coefficient of 5.3%, inter-run coefficient of variance (CV) 7.9% and sensitivity 0.2 µg/ml (Monobind Inc, United States) using Chemiluminescent assay (Berthold, Germany), and micro plate Immunoenzymometric Chemiluminescence method. Also, Interleukin-18 serum concentration was figured out with Human IL-18 Platinum ELISA, with intra-run CV of 6.5%, inter-essay CV of 8.1%m, and sensitivity of 9pg/ml (eBioscience, United States) using ELISA reader (Awareness stat fax plus , US) and Enzyme-linked Immunosorbent method. To compare the mean of pre-test in three groups, one-way ANOVA was used, and if it was significant, Post-hoc Turkey test was used. To compare the posttest means of three groups, also, One-way ANOVA, and in case of being significant, Tukey Post-hoc test was used. Statistical analyses were performed using SPSS 22 statistical software. … [34]
Findings by Text
The mean age of endurance exercise group was 21.6 ± 3.9years. It was 20.9 ± 3.6years in resistance exercise group and 21.5 ± 3.2years in the control group. The comparison between pretest weight means, body mass index, body fat percentage, Vo2max, interleukin-18 and hsCRP was not significant. Therefore, no significant difference was observed between resistance exercise, endurance exercise and control groups in levels of mentioned variables in pretest stage. However, the comparison between posttest means was significant in weight and body mass index (Table 1). Tukey Post-hoc test showed that the posttest mean of weight in resistance exercise group was more than endurance and control groups. However, there was no significant difference between endurance exercise and control groups. Also, the posttest mean of body mass index of resistance exercise group was more than that of endurance exercise and control groups. However, no significant difference was observed between the endurance and control groups. The comparison between posttest means was significant for VO2max and the posttest mean of VO2max in the endurance exercise group was more than resistance exercise and control groups, and it was higher in resistance exercise group compared to control group. The posttest mean comparison was not significant in body fat percentage, interleukin-18, and hsCRP. Therefore, no significant difference was observed in levels of mentioned variables among endurance exercise, resistance exercise and control groups.
Main comparison to the similar studies
Circulating levels of interleukin-18 after 12-week resistance and endurance exercises did not change. 10-month flexibility/resistance exercises have not changed the level of interleukin-18 serum in older adults [20]. Resistance exercise has not made any change in the levels of interleukin-18 serum in people with metabolic syndrome [19]. Unlike the results of this study, in both mentioned studies, levels of interleukin-18 serum has been decreased following endurance exercise [19, 20]. In line with the findings of this study, it has been shown that 8 weeks of endurance exercise has not significantly reduced the serum levels of interleukin-18 in men and women [35]. Despite the increase in VO2max and body weight loss after endurance exercise, no change has been occurred in plasma inflammatory markers such as interleukin-18 [21]. Increasing physical activity, independent of the level of physical fitness (VO2max) can reduce the level of interleukin-18 in some healthy Japanese men [36]. … [37] 12-week resistance and endurance exercises did not make any changes in circulating level of hsCRP in inactive lean men. Short term exercise (one session of exercise) can cause an inflammatory response, but both cross-sectional and longitudinal studies have shown that long term exercise (a course of exercise) is resulted in an "anti-inflammatory" effect. The findings of this study are consistent with findings of some previous studies [17, 19, 38], but it is contrary to some other studies [18, 39]. In line with the findings of this study, no change has been shown in the concentration of hsCRP serum after both endurance and resistance exercises in patients with metabolic syndrome [19]. Compared with the control group, the levels of circulating CRP levels have not been reduced in diabetic patients after a period of endurance exercise [38]. No change has been mentioned in CPR level in healthy young men after 6 weeks of resistance exercise with moderate-to-high intensity [17]. In contrast, other stidoes have shown the reduction of CRP serum level after 4-week resistance training in diabetic Wistar rats [18]. 12-week endurance exercises have reduced serum CRP levels, weight and body mass index in two groups of obese children (with and without metabolic syndrome) [39]. In line with this study, there is no difference in resting levels of inflammatory markers in active and inactive lean subjects, and body composition has been the main determining factor for concentration of inflammatory markers in lean subjects [40].
Suggestions
Longitudinal studies with a longer period and different exercise characteristics should be carried out in inactive lean men who constitute a certain population in terms of body mass index and fitness, along with investigating other inflammatory cytokines.
Limitations
Low subject number, short duration of exercise and uncertainty of adequate nutritional control during the exercise period are the most significant limitations of the current study.
Conclusions
Circulating levels of interleukin-18 and hsCRP do not change in inactive lean men following 12-week resistance and endurance exercises.
Acknowledgments
Participants are appreciated.
Conflict of interest
Non-declared
Ethical Permissions
This study has been approved by ethical committee of Islamic Azad University of Saqqiz.
Funding Sources
This study has been funded by the author and Islamic Azad University of Saqqiz.

TABLES and CHARTS

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