Hi nerris121 You may have noticed lately that Vitamin D is in the news about its connection to cancer and many other diseases, so it may not surprise you that Vitamin D is connected to hypertension and heart disease as well. We got scared out of the sun in the late 80s and no one bothered to tell us how we were going to get enough Vitamin D. Now, our lack of sun exposure is coming back to bite us in so many different ways. Studies show that Vitamin D level is inversely correlated to blood pressure. Meaning, the lower your Vitamin D the higher your risk for high blood pressure. Dr. Mercola, a proponent of vitamin D testing, strongly suggests getting most of your vitamin D from sunshine and during the rest of the year, or if you are dark-skinned (because dark-skinned people need many times more sun exposure), getting it from D3 supplements. Mercola suggests your optimal tested level should be 45-50 ng/ml or 115-128 nmol/l. (see links below for the proper test) The Canadian Cancer Society recently announced its recommendation that its population take a D3 supplement of 1000 IU daily. Vitamin D researchers often suggest higher daily intake. Good luck!