Interval training session questions
A bit of a newb with the lingo and regimented training (use to typically just go out and hammer), but would like some thoughts on my interval work and specifically what I experienced last night.
I don't have a PM, so this is done on a spin machine at my gym (use same bike each time).
My interval sessions look like this (maintain 100 cadence throughout):
Warm up for 15 minutes at 180 watts. This keeps me right around 70% MHR.
Then roll into my 5X5s.
1st interval: 300-305 watts. HR climbs to about 85-90% MHR.
1st recovery: 180 watts. HR recovers to about 73% MHR.
2st interval: 300-305 watts. HR climbs to about 90-92% MHR.
2nd recovery: 180 watts . HR recovers to about 73% MHR.
3rd interval: 300-305 watts. HR climbs to about 90% MHR. Breathing deliberate, but easy (controlled deep breaths). Feel really strong. Most "comfortable" interval.
3rd recovery: 180 watts. HR recovers to about 78% MHR.
4th interval: 300-305 watts. HR climbs to 92-94% MHR. Breathing more strained. Effort feels much more difficult than interval #3.
4th recovery: 180 watts. HR recovers to about 83% MHR. Doesn't feel like a recovery. Sense interval #5 going to throw me into *German accent* der hurt locker.
5th interval: 285-300 watts. HR shoots to about 95-96% MHR. Breathing almost desperate. Effort more difficult than interval #4. Power loss.
Full recovery. Low resistance pedal until HR falls below 65% MHR (5-10 minutes).
Any reason interval #3 would feel so relatively comfortable and interval #4 so tough? Felt drastically different.
Is my gas tank simply running dry (loss of power in interval #5).
Am I doing these right?
Would buying $3k wheels help? <--just kidding
Also, who else regularly powers through a spin class on their own agenda, ear bugs cranked up to drown out all the sh*tty Madonna, Erasure, etc...? Cheese and rice.