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If you partied a bit too much on Friday night, don’t hit the gym first thing on Saturday. “You can smell the alcohol coming out of them,” Williams says. Alcohol is a depressant – despite the fact that people drink it to release their inhibitions – it messes up your system. It may also have a lot of sugar which increases your insulin levels. Alcohol leads to dehydration, narrow blood vessels, and impaired motor function if you overdo it.