The primary purpose of this study was to evaluate the effect of participation in Ramadan on body composition and circulating markers of renal function, immunity and inflammation in men, who continue to perform resistance training. A second aim was to determine whether training at night (in the acutely fed state) altered the impact of Ramadan compared to when training was undertaken during the day (in a fasted state). Our results showed, contrary to our hypothesis, that whether resistance training was conducted in a fed or fasted state, no significant effect on body mass or body composition of bodybuilders was revealed after four weeks. In addition, even though Ramadan fasting induced changes in urinary and some biochemical parameters, these changes were not different according to the state (fed vs fasted) in which training occurred.
Body mass and body composition did not change in either FAST or FED during Ramadan. Our results do not concur with the other published studies [4, 27]. For example, Trabelsi et al.  demonstrated that fasted-state aerobic training resulted in a decrease in body mass as well as fat percent in physically active men. However, those changes were absent if an equivalent amount of aerobic exercise was performed in a fed state during Ramadan . The discrepancy between that finding and the present study is likely due to a difference in the exercise regime; aerobic exercise will provide a better stimulus to induce fat oxidation than does resistance training. Notably, participation in Ramadan alone appears to improve the ability to utilize lipid during aerobic exercise , perhaps, providing an increased opportunity to reduce body fat stores if exercise is performed regularly during the fasting month. It appears that despite participation in Ramadan, lean body mass was maintained with no increase in body fat percentage. This may be largely because of the lack of change of training volume in this bodybuilder cohort. In addition, it is worth noting that energy and macronutrient intakes did not change during Ramadan and were consistent with the recommendation proposed by Slater and Phillips  for bodybuilders to induce hypertrophy. However, the use of a non-invasive method to measure changes in body composition (e.g., DEXA) in future studies of Ramadan is warranted to confirm this finding.
Urine specific gravity increased during Ramadan in both groups, which is consistent with some degree of dehydration , was previously observed with high intensity exercise training . This state of dehydration has been previously attributed to a reduction of fluid intake [2, 5, 6]. It is likely our results can be similarly explained. However, in our previous work we have observed the urine specific gravity of subjects performing aerobic exercise before breaking the fast increasing during Ramadan, but absent in subjects practicing the equivalent amount of aerobic exercise after breaking the fast . However, it is worth noting that our subjects had only about 4 hours to consume food or fluid after sunset on the day before the sample collection during Ramadan. It may well be that this was insufficient time to allow full hydration. Thus, our results concerning the hydration status of our subjects may be influenced independently of Ramadan. Markers of renal function showed a similar trend, increasing in both groups. Those findings were previously observed in subjects practicing aerobic exercise during Ramadan . Sodium and chloride concentrations increased in both groups during Ramadan. A chronic state of mild dehydration in both groups may explain the abovementioned increase of serum electrolytes and renal function markers. Interestingly Ramadan fasting did not affect serum potassium concentrations in FED. Due to the dehydration and the elevations in serum sodium that occurred in FED, one might expect that increases in serum potassium concentrations would also be observed. However, a decrease in potassium intake may have offset any effects on serum potassium caused by dehydration .
HDL-C increased during Ramadan in FAST and FED, at variance with our previous work . The rise in HDL-C was explained previously by change in body mass [2, 33] or fat intakes . However, in the present study, body mass did not change in either group while fat intakes increased only in FED. Thus, the rise of proportion of fat intakes during Ramadan can explain the increase in HDL-C in FED; although mechanisms by which fasting increases HDL-C in FAST remain unclear. Further investigation is needed to resolve this issue.
Whether Ramadan fasting affects cellular damage was also investigated in the present study. Serum CK, ALT, AST, ALT, AP and γ-GT were measured to assess the effect of Ramadan fasting on cellular damage biomarkers of bodybuilders. Ramadan fasting did not affect any of these variables and is in accordance with previous reports observing sedentary persons . Nevertheless, to our knowledge, our study is the first to investigate the effect of Ramadan fasting on these parameters in men who undertake resistance training during Ramadan.
Serum C-reactive protein concentrations reflect the activity of cytokine-mediated inflammatory processes and are roughly proportional to the extent of tissue injury . C-reactive protein did not change in either group and this perhaps could be explained by the lack of effect of Ramadan fasting on cellular damage biomarkers. Akin to previous studies in judokas , Ramadan had no impact on leukocyte count. Thus, in this context at least, continuation of resistance training whilst participation in Ramadan can be performed safely.
It is worth noting that effect sizes of the parameters measured in the current study were consistent but rather low. This, and the small number of participants my have resulted in type II error for some of the parameters measured. With this in mind, replication of the study with more participants during Ramadan would be difficult because of recruitment, but may result in further significant findings. Nevertheless, we have previously observed metabolic changes with participation in Ramadan with similar numbers of subjects .