There were plenty of athletes who have collapsed before COVID-19...
Some of these athletes include Yohann Diniz, Callum Hawkins, Jonny Brownlee, Jonathan Busby, Hayley Carruthers, and Kemoy Campbell.
https://www.dailymail.co.uk/news/article-3752875/Brave-French-athlete-collapsed-twice-suffered-embarrassing-stomach-problem-50km-race-hits-IOC-setting-event-hottest-time-day.html
https://www.abc.net.au/news/2018-04-15/comm-games-organisers-criticised-over-marathon-runners-collapse/9660742
https://www.outsideonline.com/health/training-performance/why-do-so-many-triathletes-collapse-just-finish-line/
https://www.thesun.co.uk/sport/athletics/10021090/diana-mezulianikova-collapses-800m-doha/
https://www.dailymail.co.uk/news/article-6968899/British-athlete-Hayley-Carruthers-collapses-just-finish-London-Marathon.html
https://www.si.com/olympics/2019/02/12/kemoy-campbell-collapse-hospitalized-awake-millrose-games-jamaican-olympian