Because I live near a local running track, I'm wondering if there are any significant losses to the effects of HIIT by doing it by distance, rather than time?

What I'm planning on doing is sprint 400m (1 lap) walk 100m, sprint 400...

Do that a few times over and I'll end up starting the sprint from the same place, which should equal 1 mile sprinting?

Any significant losses to doing it this way? I hate having a stopwatch on me as I run.

truthfully I would say that 400m is probably to far and I would say go with 200m intervals

You would not be able to truly call this HIIT because your inetensity levels will HAVE to drop to lower levels 75-85% So it would nto be HIIT it would be lactic training with intervals (moderate intensity interval training)

True HIIT will last no more than 100 yards (if that) Most will lack the technical form to truly push 95-100% intensity.

When it comes to what you will lose....well.....what are you hoping to achieve??

I believe the Tabata protocol calls for high intensity intervals of 20 seconds and a 10 second rest interval. Since this is the report that started it all (HIIT), and has all the tests and results, I would think that it should be the one to follow.

Aerobic training article: In Search of the Ideal Aerobics Routine

Tabata is considered that wrongly. Tabata is a form of high lactic acid training. Effective in what it does, but the simple fact remains your body will be using its glycolysis energy system when workout periods are higher than a few seconds and the rest periods do not allow for ATP/CP to be restored (3-5 minutes)

Are you saying that if your high intensity interval (90% +) is for 1 minute, that your rest interval should be 3 to 5 minutes?

Not exactly,

What I am saying is do not get confused on what is high >95% and what is not. Even if someone was capable of holding on to a 90% or higher power output for a full minute, the partial recovery that follows will assure that he/she will not be able to deliver the same power output a second time around.

Keep in mind, it all will depend on what your individual goal is for using interval training whether it truly be high or not.

Agreed.. All through High school cross country and still today when i train for 5k's my speed workouts consist of HIIT workouts on the track. The most effective i've found is to Sprint the corners and jog the straits for a mile, and then Sprint the corners and jog the straits for a mile. After that just jog a mile to sustain some endurance and let the heart rate calm down again.