We have known for a long time that increasing weight may lead to increases in blood pressure. Now a Norwegian study of more than 15,000 individuals has determined that obese women are more likely than lean women to increase their blood pressure if they gain weight.

For a given increase in BMI (body mass index), obese women had greater increases in both systolic and diastolic blood pressure than lean women. In men, the blood pressure change was associated with increased BMI, but was not related to BMI at baseline - that is, the increase in blood pressure seen in men was the same whether or not they were obese at the beginning of the study. Thus it's even more important for women who have a high BMI not to gain more weight.

Source:  Wilsgaard T, Schirmer H, Arnesen E. Impact of body weight on blood pressure with a focus on sex differences. Arch Intern Med, Oct. 9, 2000.