New research shows that performing intense exercise for just 12 minutes causes changes in blood levels of substances linked to cardiovascular health. The study used data from the Framingham Heart Study of 411 middle-aged adults. Researchers analyzed levels in the blood of volunteers of 588 substances involved in metabolism (metabolites) before and immediately after 12 minutes of intense exercise on an exercise bike. In more than 80 percent of the metabolites, the investigators observed changes, including beneficial changes in those related to diabetes and heart disease. Exercise, for instance, has had beneficial effects on metabolites linked to insulin resistance (a disease precursor to diabetes), lipolysis (fat breakdown), inflammation, and reactivity of the blood vessels. These advantages in people with obesity seem to have been blunted. The exercise-related metabolites could provide specific "signatures" in the bloodstream that could reveal whether a person is physically healthy, according to the authors, similar to the way blood tests show how well the kidney and liver work.