It's the endorphin release that actually changes our mood from exercise - not the sweating. And, it's the mood change I liked at that point, anyway.
Got me thinking about water and cleansing and the whole sin/baptism thing. According to Acts 22:16, baptism washes our sins away: "get up, be baptized, and wash your sins away", The Lord told Paul during his conversion. John 1:31 describes John's baptism as "a good bath, scrubbing sins, giving you a fresh start with God".
So, is it really baptism that washes our sins away? That's like saying the sweat coming out of bodies is what makes us feel better, when it's really what's going on in our brain, and the hormones released there. If it were just the sweat, I'd feel great after dripping while watching my daughters play soccer all day in the 90 degree heat, but it doesn't work that way.
1 Peter 3 explains pretty well that the waters of baptism don't wash away dirt from our skin, "but present you through Jesus' resurrection with a clear conscience." Baptism symbolizes dying (going down in the water) and being raised again with Christ (coming up out of the water), which is how we are cleansed from sin, and given that clear conscience that we could never get on our own.
I checked out the meaning of the song that inspired me here ("Washed By The Water") and discovered that it's about the singers' dad who was a preacher whose congregation was gossiping about him. The preacher stood strong and didn't fold up under the rumors. He had been "washed by the water" - he had been given a clear conscience from Jesus.
"Keep a clear conscience before God so that when people throw mud at you, none of it will stick." 1 Peter 3:16, The Message. And that, my friends, is done in the dunking!