- History of regular alcohol consumption exceeding average weekly intake of greater than 21 units or an average daily intake of greater than 3 units (males) or an average weekly intake of greater than 14 units or an average daily intake of greater than 2 units (females). Subjects who regularly consume more than 12 units of alcohol in a 24h period will also be excluded. 1 unit is equivalent to a half-pint (220ml) of beer/lager or 1 (25ml) measure of spirits or 1 glass (125ml) of wine.