Why take Viagra or Levitra to boost sexual performance when exercise works better?

Regular exercise improves blood vessel health - the root cause of erectile dysfunction (ED). ED is a good predictor of cardiovascular disease and poor blood vessel health (endothelial dysfunction). Poor blood vessel health impairs blood flow regulation in the penis and promotes arterial disease in the heart, brain and other tissues. It also triggers high blood pressure and diabetes, which in turn leads to ED, heart attack and stroke. Risk factors for ED include age, diabetes, depression, high blood pressure and smoking. Exercise protects against ED.

Researchers from Hong Kong pooled the results of 11 studies using a statistical technique called meta-analysis and found that regular exercise decreased the risk of ED by 40%.
They concluded that regular physical activity reduces the risk of ED and can even reverse the problem in men who already have it. (International Journal Impotence Research, 19: 245-252, 2007)