Hi. While Hiking For 3 Hours In Mountainous Terrain Yesterday,

Hi. While hiking for 3 hours in mountainous terrain yesterday, my first time, I consistently sipped on ice water. I was extremely red in the face, hot, and had a lot of trouble keeping up with others, especially while going uphill. My friends, to a person, said my ill effects were due to the ice water, which I drink nearly 24/7. I should be drinking tepid (yuk!) water as it more quickly hydrates and doesn't take a toll on the spleen like ice water does. Is any of this true? Thank you!