24-hour Blood Pressure Measurements and Ischemic Conditioning

Reestablishing blood flow (reperfusion) to organs that had their blood supply restricted
(ischemia) can cause damage to the vasculature via injury and tissue death resulting in
endothelial dysfunction. This ischemia-reperfusion (blood flow occlusion and resupply)
triggered injury can be reduced or prevented by preceding brief periods of ischemia called
preconditioning. Properly-performed preconditioning can exert a powerful protection against a
subsequent sustained period of ischemia in a variety of organs in the body including the
heart, kidney, and skeletal muscle. Preconditioning protocol involves repeated brief
inflation and deflation of a blood pressure cuff. In many of human cardiovascular research
studies, it is common to measure endothelial function and ambulatory (24-hour) blood
pressure. The ambulatory blood pressure device takes repeated blood pressure readings every
15-30 minutes during the daytime and 30-60 minutes at night. It is possible that repeated
bouts of inflation/deflation of the blood pressure cuff could induce preconditioning effects
and influence endothelial function. Therefore, in the proposed study we aim to address this
hypothesis.

Inclusion Criteria:

Adults aged between 30 to 60 years old.

Exclusion Criteria:

Exclusion from the study may be due to: i) pregnancy (by asking the subjects when the last
time she had menstruation; we do have simple testing kits available if a subject is unsure
about her status); ii) a recent illness, recent surgery, or any medical intervention in the
48 hours before any of the study days; iii) personal history of diabetes (fasting blood
glucose > 126 mg/dL), heart disease, or other cardiovascular problems.