If you're planning on celebrating the New Year with a few cocktails tonight, you may want to skip your run tomorrow. Why? Well, drinking alcohol doesn't mix with running because alcohol has a dehydrating effect. Yes, it's true that it may feel good to "sweat out" your hangover, but it's never a smart idea to run when you're dehydrated.
If you really want to celebrate and then start the new year with a run tomorrow, try to limit your alcoholic beverages tonight and drink plenty of water before, during, and after your run.
Happy New Year!