321 Baudin Way, Sonoma, CA Address for correspondence: E. Randy Eichner, MD, FACSM, 321 Baudin Way, Sonoma, CA; E-mail: [email protected].

321 Baudin Way, Sonoma, CA Address for correspondence: E. Randy Eichner, MD, FACSM, 321 Baudin Way, Sonoma, CA; E-mail: [email protected].

321 Baudin Way Sonoma, CA Address for correspondence: E. Randy Eichner, MD, FACSM, 321 Baudin Way Sonoma, CA; E-mail: [email protected].

321 Baudin Way, Sonoma, CA 95476 Address for correspondence: E. Randy Eichner, MD, FACSM, 321 Baudin Way, Sonoma, CA 95476; E-mail: [email protected].

Address for correspondence: E. Randy Eichner, MD, FACSM, 321 Baudin Way, Sonoma, CA; E-mail: [email protected].

CONTEXT:Among American sports, football has the highest incidence of exertional heat stroke (EHS), despite decades of prevention strategies. Based on recent reports, 100% of high school and college EHS football fatalities occur during conditioning sessions. Linemen are the at-risk population, constituting 97% of football EHS deaths. Linemen heat up faster and cool down slower than other players. EVIDENCE ACQUISITION:Case series were identified from organized, supervised football at the youth, high school, and collegiate levels and compiled in the National Registry of Catastrophic Sports Injuries. Sources for event occurrence were media reports and newspaper clippings, autopsy reports, certificates of death, school-sponsored investigations, and published medical literature. Articles were identified through PubMed with search terms "football," "exertional heat stroke," and "prevention." STUDY DESIGN:Clinical review. LEVEL OF EVIDENCE:Level 5. RESULTS:Football EHS is tied to (1) high-intensity drills and conditioning that is not specific to individual player positions, (2) physical exertion as punishment; (3) failure to modify physical activity for high heat and humidity, (4) failure to recognize early signs and symptoms of EHS, and (5) death when cooling is delayed. CONCLUSION:To prevent football EHS, (1) all training and conditioning should be position specific; (2) physical activity should be modified per the heat load; (3) understand that some players have a "do-or-die" mentality that supersedes their personal safety; (4) never use physical exertion as punishment; (5) eliminate conditioning tests, serial sprints, and any reckless drills that are inappropriate for linemen; and (6) consider air-conditioned venues for linemen during hot practices. To prevent EHS, train linemen based on game demands.Strength-of-Recommendation Taxonomy:n/a.

Recent Recommendations in Sports Two recent articles are examples. A study of elite ballet dancers recommends testing ferritin and vitamin D levels annually, noting that “a deficit in vitamin Dmay cause deterioration of iron status and increase the risk of anemia” (1). Most of the female dancers (68%), especially those on restricted diets, had low ferritin; this is no surprise. In contrast, vitamin D status was generally adequate. In any case, the notion that low vitamin D can cause iron deficiency anemia is wrong. The authors cite a meta-analysis of seven observational studies of low vitamin D and “anemia.” Two were U.S. studies; neither tied low vitamin D to iron deficiency anemia (2,3). Low vitamin D can “travel with” low ferritin, but one does not cause the other. The other recent article recommends VDS for endurance cyclists training intensely (4). It notes conflicting results in a narrative review, and cites one study, showing that VDS boost aerobic fitness in soccer players (5). But in that study, V̇O2 max rose 2.6% in those on VDS (P = 0.03) versus 2.2% in those not on VDS (P = 0.053). All told, weak support for recommending VDS to endurance cyclists. I will return to VDS for athletes. First, the track record for VDS in the practice of medicine.

Address for correspondence: E. Randy Eichner, MD, FACSM, 321 Baudin Way, Sonoma, CA; E-mail: [email protected].