At this point in time, there's no reason to be spiking anything like that. It is going to grind you down so quickly, that any steady state ride longer than an hour, is going to kick you into the dirt. You flat do not recover from stuff like that in a couple of days, simply because your body isn't ready for that stress. Stress is an evil mother, and you have no idea you're upside down until it's too late.
So if I wanted to do intervals, using a power and time should I keep under 400? 500?
example 3 mins at 150 followed by 30 seconds of 350?
Im new to the interval thing. Obviously I have no idea what I am doing.