ABC:
In an email to participants Tough Mudder wrote:
"We are reaching out, as we are aware of some reports of individuals experiencing an adverse health reaction following participation in the Tough Mudder Sonoma event this past weekend.
We want to let you know, that the health and safety of the Tough Mudder community is always our top priority, and accordingly, we are actively taking all necessary steps to fully investigate the matter.
If you are experiencing any medical concerns, please consider seeing your doctor.
We thank you for understanding and patience as we continue to look into the matter.
Meanwhile, posted a few hours ago, "Are you tough enough for Arctic Enema?":