Why Should You Avoid Drinking before Cardio and Resistance Training?
There is evidence that drinking before a workout, particularly cardio will hinder your workout.
Evidence shows you’ll get fatigued quicker and take longer to hit your usual goals. The extra fatigue that comes from drinking is the result of the citric acid cycle slowing down, the pathway known as gluconeogenesis is inhibited, which effectively means less glucose for the body to use, in other words less energy.
Also the body prefers to metabolize alcohol and alters the metabolism of carbohydrates and lipids, so you wont hit those goals.
Rather save the beer for after your workout.