Sentence 1: Ed didn't like to wear anything on his head. 
 Sentence 3: He'd avoid staying out too much for that reason 
 Sentence 4:  But every year he caught a cold because of it 
 Sentence 5:  Eventually he bought a hat even if he despised them 
 Option 1: He was so used to it that didn't even get cold in winter. 
 Option 2: So during winter time, his head was always cold.