We still don't have any information about the bicyclist or what exactly happened, but Susan Christian with the city of Houston said the rider was not a child or a city employee. She says emergency crews responded, but it wasn't enough.
The Tour de Houston, which goes through some of Houston's oldest neighborhoods, gives riders the option of taking a 20-, 45- or 70-mile route.
It wasn't immediately known which route the victim had chosen and how far into the ride the medical emergency happened.
Christian says three other people were transported to the hospital during the ride, which is the lowest number the city has ever had. She said they were transported mostly because of falls.
Christian says city officials are deeply saddened by Sunday's loss and their thoughts and prayers go out to the rider's friends and family.
The bike ride is a fundraiser for reforestation programs and is recommended training for the BP MS 150.
About 5,000 people were expected to participate in the bike ride.
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