My friend wants to buy a bike, so I called him up to see if he wanted to buy one since I was going to the sporting goods store to look for one. Here is our conversation:

Me: Hey, do you want to go buy a bike today?
Him: Today? Now?
Me: Yeah.
Him: (in a strained tone): Not today.
Me: Okay, bye.
Him: (still speaking in strained and quiet tone): Bye.

I thought he sounded really strangely. I found out why in a minute when he texted, "Got the runs."

Oh.. that explains it.

Thanks to Doug and Kent who helped me find the right word to describe my friend's tone of voice.