Alcohol and drugs slow down messages that your brain sends out, making you move more slowly and clumsily.
Because of your clumsiness, you won't be able to participate in sports, since most sports require some sense of coordination.
I feel like watering down the "no" to "nah, I'm good," is a good enough method to turn down a friend's offer. Or, just like this question asks, tell your friend you have a sports-related activity soon. :)
-T.B.
