what cardio would be more efficient?

[bluebandana457]

i have had good results in the past with doing cardio on an empty stomach in terms of losing weight. i am going to limit it to twice a week though since i want to gain some muscle. i was wondering though what would be best:
doing a spin class or going 40-60min on the treadmill at a slow and steady pace. i will also be doing a spin class 4 days a week later in the morning, so i didn't know for the other two days if i should take a break from spin and do a slow and steady cardio, or if the spin is still the best way to go? thanks!

[PoetryInMotion]

so how many cardio sessions are you doing a week?

[bluebandana457]

6, monday-saturday
tue,wed,thur,sat i spin at 9:15am and i want to do 2 am sessions

[twinnett]

You're trying to gain muscle? I wouldn't recommend all of that cardio, esp. on an empty stomach