Water jogging/treading in the deep end of the pool

I really did it - one whole hour!  Of course this was with the aid of floatation devices and hanging on the safety rope that divides the deep and shallow ends.  I was afraid I wouldn't go the full hour because my arms got tired.  But my legs never seemed to get tired - my legs felt great even when I got out the water.  Several of the ladies in the pool kept encouraging to let go, but every time I did it felt as though I was going under.  Definitely need to sign up for the swimming lessons ASAP!