Which factor contributes to hypertension?

A) excessive exercise
B) sleep
C) poor diet
D) potassium

Poor diet, including excessive sodium intake and inadequate intake of fruits and vegetables, is a known contributing factor to hypertension. Excessive exercise can actually lower blood pressure, and both getting enough sleep and consuming adequate amounts of potassium have been shown to be beneficial for blood pressure control. However, poor diet is the most significant contributing factor among the options listed.