The coronavirus disease (COVID-19) pandemic is caused by a novel coronavirus (CoV) named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As the angiotensin converting enzyme 2 (ACE2) is the cellular receptor of SARS-CoV-2, it has a strong interaction with the renin angiotensin system (RAS). Experimental studies have shown that the higher levels of ACE2 or increasing ACE2/ACE1 ratio improve COVID-19 outcomes through lowering inflammation and death. Aerobic moderate intensity physical exercise fights off infections by two mechanisms, the inhibition of ACE/Ang II/AT1-R pathway and the stimulation of ACE2/Ang-(1–7)/MasR axis. Exercise can also activate the anti-inflammatory response so that it can be a potential therapeutic strategy against COVID-19. Here, we summarize and focus the relation among COVID-19, RAS, and immune system and describe the potential effect of aerobic moderate intensity physical exercise against CoV as a useful complementary tool for providing immune protection against SARS-CoV-2 virus infection, which is a novel intervention that requires further investigation.

Background The insertion (I) rather than deletion (D) of human angiotensin converting enzyme gene (ACE) is associated with lower circulating ACE activity and with endurance performance among Caucasians. The frequency of the ACE gene I/D allele in Iranian sample seems to be more similar to the Caucasians. To assess the possible relationship between I/D polymorphism of ACE gene with athletic status and selected cardiovascular indices and VO 2max in an Iranian population, DNA samples were obtained from 57 trained and untrained men, with soccer as their main training modality. Genotyping for ACE I/D polymorphism was performed using polymerase chain reaction. VO 2max was determined by an incremental test to volitional exhaustion on a motorized treadmill. Results I/D genotype was neither associated with elite athlete status nor with VO 2max , resting heart rate, systolic and diastolic blood pressure. There was no interaction effect of training statue x ACE genotype for each of the examined indices. Conclusions ACE gene variation was not a determinant of cardiovascular function and VO 2max in either trained or untrained Iranian participating in soccer. The absence of an association between either I/D genotype and elite Iranian athlete status and better cardiovascular function also suggests that the ACE gene does not contribute significantly to the phenomenal success of Iranian soccer players.

The effects of exercise on kidney function have been studied for more than three decades. One of the most common health issues among patients with chronic kidney disease (CKD) is a lack of physical activity, which leads to a low exercise capacity in these patients. The majority of maintenance hemodialysis (MHD) patients do not exercise at all. At each stage of dialysis, patients lose 10–12 g of their amino acids through blood sampling. Dialysis also leads to increased cortisol and circadian rhythm sleep disorders in hemodialysis (HD) patients. Studies have also reported higher C-reactive protein levels in HD patients, which causes arterial stiffness. Exercise has a variety of health benefits in these patients, including improved blood pressure control, better sleep, higher physical function, and reduced anxiety and depression. On the other hand, it should be noted that intense exercise has the potential to progress KD, especially when conducted in hot weather with dehydration. This review aimed to investigate the effects of different types of exercise on kidney disease and provide exercise guidelines. In conclusion, moderate-intensity and long-term exercise (for at least a 6-month period), with consideration of the principles of exercise (individualization, intensity, time, etc.), can be used as an adjunctive treatment strategy in patients undergoing dialysis or kidney transplantation.

Regarding the muscular weakness in patients with Multiple and the importance of the 2nd digit to 4th digit (2D:4D) ratio as a representative of the androgen level in women, the aim of this study was to investigate the relationship between level of physical activity, handgrip strength and 2D:4D ratio with the incidence of multiple sclerosis. This cross-sectional study was conducted on 100 female patients with average age of 35.01 years, BMI 24.04 kg/m 2 and disability development scale of Kurtzke (EDSS) equal to 8.5-0 among the patients of Shariati, Imam Hossein and Rasul Akram hospitals in Tehran in time intervals of December 2015 to June 2016. Hand grip strength variables were measured using the dynamometer, the 2D:4D ratio was measured with a digital calliper and the participants' physical activity were measured using the Beck physical activity questionnaire and EDSS of patients was determined by a Neurologist. The study data was analysed using statistical methods of Pearson and Spearman correlation analysis. There was a signifi cant relationship between the physical activity level and EDSS (P<0.01) and the handgrip strength with the EDSS level (P<0.05) in MS patients. However, there was no signifi cant relationship between the 2D:4D ratio and EDSS level. Based on these results, it seems that, the increase of physical activity level and the hand grip strength is associated with a reduced level of disability in patients with multiple sclerosis. Therefore, it is recommended to prescribe an exercise program which is in accordance with MS patients' condition.

The purpose of this study was to determine the (i) cardiac biomarker (cTnI and NT-proBNP) responses to moderate-intensity continuous exercise (MICE) and highintensity interval exercise (HIIE) in the middle-aged and young groups, (ii) relationship of post-exercise cardiac biomarker release between these two age groups, and (iii) investigate whether insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene is associated with predisposition to cardiac damage after exercise in Iranian men. Methods: We examined cTnI and NT-proBNP in 29 middle-aged (54.5 ± 4.6 years) and 28 young (22.7 ± 4.2 years) soccer players before and after HIIE and MICE running tests. Results: The middle-aged soccer players had higher baseline cTnI (0.015 ± 0.007 ng/ml vs. 0.010 ± 0.006 ng/ml; P = 0.01) and NT-proBNP (30.7 ± 13.6 ng/L vs. 18.4 ± 8.3 ng/L; P < 0.001) values compared with the young group. The changes with exercise (cTnI: 13 vs. 11 ng/ml and NT-proBNP: 18 vs. 11 ng/L) were also higher in the middle-aged group. No subject exceeded the upper reference limit for cTnI and NT-proBNP. Considering three ACE genotypes, the mean cTnI and NT-proBNP values of middle-aged and young groups did not show any significant difference. Conclusion: Marked differences in baseline and post-exercise cTnI and NT-proBNP values were observed, which were related to age differences but not to ACE genotypes.