Anyone who has ever ‘greened out’ after too deep a toke knows that cannabis does affect blood pressure. Studies have shown that cannabis use increases your blood pressure when you sit or lie down, but it sharply drops whenever you stand up. Is it enough to make weed effective against hypertension? We wish it were that easy. THC will generally raise your blood pressure (and heart rate), making hypertension even worse and increasing the risk of heart issues, but your body will develop tolerance to these effects with long use. This creates another risk for hypertension, when the use is abruptly stopped and high blood pressure becomes one of the withdrawal symptoms. Unlike THC, CBD does the opposite: it lowers blood pressure and heart rate, and in the case of repeated use, it dilates blood vessels and makes them more elastic, which makes low-THC, high-CBD strains actually good for hypertension.