HIIT on Eliptical

Brighamy

Hi folks - I'm quite new here, so bear with me please.

Tried a HIIT session on my nordictrack eliptical tonight, and I'm struggling to see how the benefits outweigh a standard session on the eliptical.

I am a 5ft 8in male of 52yrs and weigh 11st 7lbs (161lbs).

from my research on HIIT I came up with the following workout:

5mins warm up at level 2 at 60rpm to get HR up to 120ish
min 5-6, level13 at 80rpm, elevating HR to 170
min 6-9, level 2 at 60rpm, resting. HR back down to 128 -130
min 9-10, level 13 at 80rpm. HR 170-172
min 10-13, level 1 at 60rpm. HR back down to 130
min 13-14, level 13 at 80rpm. HR 172-174
min 14-17, level 1 at 60rpm. HR back down to 132-135
min 17-18, level 13 at 80rpm, HR 174ish
min 18-21, level 1 at 60rpm. HR back down to 132-135
min 21-22, level 13 at 80rpm. HR 174
min 22-25, level 1 at 60rpm. HR back down to 134ish
min 25-26, level 13 at 80rpm. HR 174
min 26-31, level 1 cool down.

Now my questions are as follows:
1. Is 6 x 1min high intensity levels enough (Not sure I could do any more, mind you!)?
2. According to my eliptical. I burned 400Kcals, so allowing for the 40Kcals I would have burned just sitting on the setee, thats 360Kcals in 31 mins (Net). On a steady state cardio workout for 40mins I generally burn 580-620Kcals (Net) . So on average I am anywhere between 220kcals and 260kcals down per workout.

Now I will say that I was more knackered at the end of the 31 min HIIT experiment than I normally am after 40 mins of steady state, but to me the arithmitic doesn't appear to work out.

Hopefully some of you will know a lot more about this subject than I do and can put me right.

Also should I be worried about how high my HR is going - I believe my max should be 168, but I dont feel like passing out or anything?

Best regards

Brighamy.