Scientists suspect that chemicals in the red wine (polyphenols) inhibit a chemical that causes blood vessels to constrict.
Furthermore, alcohol in general has been linked to increased levels of so-called good cholesterol. It also reduces substance that can cause blood clots.
Any benefits from alcohol seem to involve drinking small amounts spread throughout the week, rather than the total amount all at ones on a night out. Exceeding two drinks per day is linked to increases in blood pressure, and heavy drinking raises the increase of stroke and can cause swelling of the heart as well as irregular heartbeat. Immoderate drinking causes this and other risks to outweigh any positive effects of alcohol on the cardiovascular system. Always remember that too much of a good thing is precisely that –too much, or bad.