Endurance training and L-arginine intake: Their effect on antioxidant indices in the heart muscles of rats Dara Latif Saifaddin et al. (2023) conducted a study investigating the effect of endurance training and L-arginine (an amino acid in the body that helps with building protein) supplement intake on the antioxidant indices in the heart muscles over 8 weeks. Antioxidants are substances that shields the body from free radicles, which may be responsible for cancer (Slide Show: Add Antioxidants to Your Diet, n.d.). To do this, 32 young Wistar rats were purchased from Pasteur Institute of Iran and were subjected into 4 groups: control, endurance training, L-arginine, and endurance training coupled with L- arginine. Rats in the endurance training group trained on a motorised treadmill for 60 minutes per day, 5 times a week for 8 weeks. In the L-arginine group, rats were fed with L-arginine daily. I will argue that this investigation complies with ethical standards. Throughout the experiment, researchers adhered the Guide for the Care and Use of Laboratory Animals (Jones-Bolin, 2012). Although such guideline is not renowned, the rats were kept in cages at room temperature, controlled humidity, and 12-hour light dark cycle. Hence, rats were not mistreated but looked after with care, which reduces any possible psychological stress, as well as increasing the ecological validity. However, to collect the heart tissue with the purpose of measuring the concentrations of glutathione peroxidase (GPX), malondialdehyde (MDA), and superoxide dismutase, rats were terminated 12 hours after the final endurance training. Although one may argue that this may be unethical, anaesthesia was the method chosen thus the rats would experience no pain or suffering during this process. Furthermore, as this study bring insights into how sports and L-arginine affect the heart, such knowledge could be applied to better our lives, especially in elders, by maximising antioxidants to prevent the harmful free radicles which causes cancer. Based on the utilitarianism framework, the potential benefit from this investigation outweighs the suffering of the rats because the researchers are trying to reach a morally important goal, hence I believe that this investigation may be considered ethical. One may argue that the researchers could have been motivated by lucrative purposes which poses a risk involving the trimming of the data for a desirable outcome or being irresponsible handling of the data, I believe this is not the case. It was clearly stated that the authors received no financial support for the research, and the publication itself does not bring payments. However, it could be possible that they wished to gain visibility from the public to get recruited by a more prestigious institute, which could motivate them to manipulate their results for a statistically significant outcome. - No limitation - If manipulated, data would have been skewed, it wasn't.