This question is about Running
Vitamin B12 is good for runners, as it plays a role in energy production, glucose uptake, red blood cell formation, DNA synthesis and central nervous system function. It is also used to keep the body’s nerves healthy, as well as prevent tiredness and weakness [ 1
U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - vitamin b12. NIH Office of Dietary Supplements. Retrieved September 20, 2021, from https://ods.od.nih.gov/factsheets/Vitaminb12-HealthProfessional/