RT Journal Article SR Electronic T1 Low cardiorespiratory and mitochondrial fitness as risk factors in viral infections: implications for COVID-19 JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 413 OP 415 DO 10.1136/bjsports-2020-103572 VO 55 IS 8 A1 Johannes Burtscher A1 Grégoire P Millet A1 Martin Burtscher YR 2021 UL http://bjsm.bmj.com/content/55/8/413.abstract AB