Dude, it's not healthy for you. NOT HEALTHY AT ALL.
Think of it this way. That hour you spent running you probably burned around 500-600 calories depending upon your pace. That 32oz mountain dew is 500 calories itself. Not to mention it's also 122g of worthless carbs and 122 grams of bad sugars. It's essentially liquid fat.
You're literally accomplishing nothing during your workouts by continuing to drink that swill.
It's a friggin soda. It's one of the easiest things in life to resist. Man up!
*raises a 16oz glass of water to your health*