[ggreer]

While those with NCS worry more about it, head injuries from falling are a concern of everyone. At almost every cross-country or track meet I've been to, at least one runner has collapsed from exhaustion or lack of oxygen to the brain. Some are more prone to it than others, but it's a risk that participants are aware of and accept. Races rarely happen on asphalt or cement, so falls (by themselves) aren't as dangerous as you might think. It also helps that, even while losing consciousness, runners tend to stick their arms out and cushion their fall.

For most distance runners, their biggest worry is getting trampled. Racing shoes have metal spikes on the bottom.[1] Like fainting, some are more prone to getting trampled than others (typically smaller runners). I've fallen at the start of a race and had my ribs cracked and skin perforated. It's certainly not fun, but it's a risk everyone accepts.

1. https://en.wikipedia.org/wiki/Track_spikes