Employee was driving rock truck. He did not feel well. His wife spoke to him at 4 PM & he was fine. He told her he was working until 6 PM. He went to the company rental house for the night. He returned to work on 2-2-08 and worked approximately 3 hours. He left to go home. He drove for about 4 hours & called home. His son-in-law transported him to hospital.