Peanuts by Charles Schulz for March 27, 1969
Transcript:
Charlie Brown stands on the pitcher's mound. He sweats and gasps for air. He says, "Whew, I'm exhausted! I don't know if I can throw another ball."<BR><BR> Linus runs toward Charlie Brown with a glass and says, "You need a drink of my special balanced electrolyte solution, Charlie Brown . . ."<BR><BR> Charlie Brown drinks from the glass. Linus says, "This replaces the body stores and prevents any diminution of vitally needed electrolytes and nutrients."<BR><BR> Charlie Brown wipes his mouth and smiles. He says, "Thank you . . . I feel better already . . ." Linus walks away and says, "Keep the ball low!"<BR><BR>
But it wasn’t widely available in 1969. Mostly used by pro athletes.