People who drink sugar-free and artificially sweetened soft drinks are more likely to have high blood pressure, possibly because they are more likely to gain weight. Caffeine can cause a spike, too. Research shows that in hypertensive individuals, caffeine intake produces an acute increase in blood pressure for 3 or more hours. Alcohol can raise your blood pressure too much. A study says that the regular consumption of alcohol raises blood pressure. The global estimate holds that the risk for hypertensive disease attributable to alcohol is 16 percent.