Complex sentence: Unfortunately for Guto and Sian the race took a fatal toll on Guto's body as during the post-race celebrations he collapsed and died in his lover's arms after a congratulatory back-slap.
Split into simpler sentences: Unfortunately for Guto and Sian the race took a fatal toll on Guto's body. During the post-race celebrations he collapsed and died in his lover's arms after a congratulatory back-slap.