So I have been slowly working with my C25k app for a couple of weeks. Sometimes it goes better than other times. Anyway, today when it got to the jog part...i went faster (due to the music that I was listening to pumping me up!)  Anyway, in some ways running faster actually felt better for some reason.  I mean, I was more out of breath and everything but the way it felt on my legs seemed easier somehow. That leads me to this post and my question. What speeds on the treadmill do other's do? I find when it says walk, i am at around 2.5.  and jog has been between 3.8 and 4.0.  But today I went 4.5.   I don't know if I am doing it too fast, too slow etc. The app doesn't really give you that info. 

I think it is just whatever you are comfortable with.  I use a heart rate monitor to gauge my intensity.  You can get a chest strap that most gym equipment will pick up and display your HR.  If interested, google about.com heart rate and there is a good discussion or target heart rates.

I am  just the opposite, I feel more comfortable walking than running.  I walk 80% of the time at 3.8 and when I do run, it is at 5.2.

I agree that it's just what you feel comfortable with and can sustain.  It's sort of trial and error and you'll figure it out with time :)  

The rule of thumb, however, is not to increase your mileage by more than 10% in a week.  So if you ran 5 miles last week, you shouldn't run more than 5.5 miles this week.  

Sounds like you are doing an amazing job on your journey to continue to be a runner.  As for treadmill speeds others use, don't worry as it can make you feel bad about your progress at this time.  My paces today are much slower than they used to be because I neglected my run for one reason or another.  I used to be able to run 9 miles at a 10:00 min mile pace  now I am working to get back to a sub 30 5K which would translate to a 30 min 5K off the bike for me.

As for your comfort at various speeds, your body will begin to adapt and become more efficient at various speeds making sower speeds uncomfortable.  I Train by Heart Rate at times and I know I am very uncomfortable running at a lower heart rate, so much so that my coach would get pissed because I would break the training plan.

There are a couple ways to train HR (Heart Rate) or PE (Perceived Exertion).  Running is a all about efficiency and learning to be efficient takes some knowledge.  

You have what are called HR Zones and this is how hard your heart is working at a set Beats Per Minute, these zones are different for each person.  My Zone 4 (I want to die and my heart is going to explode out my chest) Can be someone elses Zone 2 (Easy)  as you work harder, go faster, your heart has to work harder.  The guy who finishes the 5K in 20 minutes probably has the same Heart Rate as you do at your fast run, the difference is that with training his body has become more efficient.  PE is going by how hard it feels.  Your runs at this point should be conversational on the slow parts, meaning you can carry on a conversation with someone.  Your fast intervals should be at the point you can probably eek out one or 2 short sentences.   or Slow Breathe Through Nose naturally, Fast focus to breathe through nose.  Your max interval you can't breathe through your nose no matter how hard you try.

While starting to run a treadmill can be a great tool as it teaches you what various paces feel like and you get used to it.  This is an ideal time to play with your speeds during intervals as they are still probably relatively short.

Some workouts I do are Pyramids or russian ladders.

Pyramid

Walk interval

Run Interval

Walk Interval 

Run Interval +n

Walk

Your walks can be at the same speed or progressive in relation to your run. Run intervals can be say .1 faster increasing through half the set intervals and then decreasing for the second half.

4min Russian Ladder

3 min walk, 1 minute run

2 minute walk, 2 minute run

1 minute walk, 3 minute run

2 minute walk, 2 minute run

3 minute walk, 1 minute run

your run and walks should be at the same speed per interval with your run being a bit beyond your comfort but at a pace you can finish.

If you have a HR a workout called over unders can be a great workout.  This where you hold a Zone 3 for a period then go zone 4 for a period then back down to zone 3.  This is what makes your heart more efficient and causes your body to build the required physiological systems needed.

Keep up the great work.

Great post Paul.  I am trying to figure out my zones.  On the elliptical, I can push my HR much higher than running.  Running, max is about 160-165, on the elliptical I can hit 175-180.  

I did work with a cardiologist to make sure how far I could push my HR.  The charts say my max should be 168, he told me 170-180 would be ok.

Remember the chart is based on an Average and various formulas but will be different for each person.  My max is like 185.  

Best way to determine your zones is to find a place and have it tested some fitness clubs do it the other option is a VO2max test (these suck).  If you don't have access to a test there are protocols for calculating it if yo have an HR.  I believe it is something like a 10 minute easy warm-up and then 20 minutes as hard as you can, BUT!! at a pace you can maintain for the whole duration.  You should end at the same pace as you started. So NO starting at a 9 minute pace and finishing at a 12 minute pace.  This will establish you LT Lactate Threshold.  One you have this number calculating your zones is simple math.  If you are going for endurance most your work should be High Zone2 mid Zone3  this keeps that Lactatic acid from building up in your legs.

Also remember that Different Activities will have different Zones.  Cycling and Running zones typically are very different for people. As stupid as it sounds 2 Heart Beats can be the difference between going all day or only lasting 20 minutes.

This link has a common LT Test.  Once you know your LT you can then figure out your Zones.

http://www.beginnertriathlete.com/cms/article-detail.asp?articleid=633

You will have a sweet spot...it is the speed where you can go forever and actually get somewhere in a time you consider decent.

It sounds like your sweet spot has a faster pace than mine. Consider yourself blessed!