Aerobic vs Anaerobic

My vitals:

Age: 41

Weight: 190

Height: 5' 11"

maxHR: 180 bpm

60%-70% low intensity zone 108-126 bpm

70%-80% Aerobic (intermediate) zone 126-144 bpm

80%-90% Anaerobic (high intensity zone) 144-162 bpm

I weight train on universal machines for 25-30 minutes every other day. I do treadmill everyday. Usually 30-45 minutes on weight days and 45-75 minutes on off days.

The question I have is the paces at which I walk 3.0 mph warmup 2-3 minutes, 3.5 mph warmup 2-3 minutes. Then I kick it up to either 3.8 mph or 4.0 mph for the rest of the walk and have a 3-4 minute cool down period at the end.

I can do 3.8 mph and 4.0 mph,which is brisk but I can do it and not get fatigued for long periods, and I can even do 5 or more minute burst at 4.5 mph. Now finally to my question, my average heart beats per a minute are 148-152 at 3.8, 151-153 at 4.0, and 160-162 at 4.5 mph. As you can see the majority of what I thought was my aerobic/cardio time is at a heart beat rate in the anaerobic. My first goal is to get my BMI down to a normal ratio which means I need to loose another 15 lbs.

What is working out in the anerobic range doing verses backing off and doing the aerobic levels? Will I loose fat slower or just turn fat into muscle?

First of all how do you know your MaxHR?  If you used the 220-age, it might be close, but at best it is a guesstimate.  Your max may be higher, or lower than that.  So the ranges are really only estimates as well.  It's better to go by how hard you feel you are working.

All exercise has some aerobic and anaerobic input.  So there is no absolute threshhold between them, usually it's a mix.  It's more about how you feel.  If you feel like you can do something for a long time --- more than 5 minutes, it's probably mostly aerobic.  If it starts making you feel like your "sucking air" after 1-2 minutes, then it's pretty anaerobic. 

The thing is BOTH of them are good for you.  In fact, anaerobic exercise can be very good for you -- google HIIT if you want to learn more about it.  However, it's not somethng you should do every day or even more than 1-2 times per week.  The aerobic type of exercise can be done daily 5-6 days per week. 

Can I tag along on this thread?  My resting heartbeat is pretty high (somwhere higher than 70) which makes it difficult to do almost any workout within the aerobic zone.  I can go up to a little over 4 mph without sucking air, but as soon as I start jogging I know my time is limited.  My question is, what is the best method by which to increase one's upper threshold of aerobic activity?  If I stay around 4 I can speed walk forever, but it doesn't seem to help me with jogging.  Will increasing the time spent in anaerobic territory ever allow me the add a slow jog to my list of aerobic activities?  If not, does this mean I can really only jog in spurts and even then only a couple times a week?

@kayola -- Yes, doing anaerobic workouts can increase your aerobic performance.  It doesn't work forever, and I believe it's Melkor who recommends doing HIIT for 3-4 weeks and then spending 6-8 weeks on eith regular intervals or steady state.

Also, if you are new to cardio, and stick with it, your resting heart rate will likely come down. 

Not all interval training is HIIT though.  I worked my way up doing regular IT before I learned about HIIT and it can be done a lot more often.  That where you walk to warm up and then --considering the niumbers you gave - maybe try jogging at 4.2 MPH and see if you can do 2-3 minutes.  During new sessions I would try to push myself a little harder or a little longer until eventually I could jog 2-3 miles at a time. 

I've found, that for me walking 4.0 MPH is harder than jogging at 4.2 or even 4.5  Myabe it's because of my short legs. lol.

Just remember not to try to do too much too fast.  The "couch to 5K" program is a more refined version of what I did, but it progressed too fast for me. 

@kayola, my resting heart rate is ~90 BPM. And I'm in a similar state can walk at 4 mph for ever but I do 1-2 minutes at 4.5 mph about every 10-15 minutes during my workout. I did this when 3.0 and 3.5 was my comfortable speed and have been able to steadily increase top speed by about .5 mph every 2 weeks or so.

I'm going in for a EST (exercise stress test) next week so hopefully I can validate or tweak my numbers at that time.

Hello all. Well im 5' 11 255 pounds. i went from never exercising to being able to run at 5.5 mph for twenty minutes in about three weeks. at first i would walk 3.5 mph and every once in a while run 5.5 for about 30 seconds before feeling like im gonna die. every day i just worked at doing it more. first thirty secs then one min. from one minute to two then five.  i also noticed that when i was running that thirty seconds my heart rate would be racing in the 170s mark. now it only goes that high if i do a 8mph interval for a minute. running 5.5 gets me to about 155 bpm. i think its all about pushing yourself to do more every day. in the last three weeks i also lost 14 pounds... running seems to do the trick for me.

That's great, just remember not to try to do too much too fast.  If your body isn't used to running you can injure yourself.  Look at all the posts here about shin-splints and stress fractures -- overtraining is not good. 

Also, if you try to do really intense training too often your body doesn't get a good chance to recover and you can actually do damage.  There was a guy on here who was doing HITT 5-6 days a week and I think he ended up with some heart problems because of it.

Well, im gonna go one more week as much cardio as i can. then im gonna tone it down and start lifting weights more. Planing on taking a much more slower approach. we are doing a weight loss competition and trying to win.

I noticed something today, I will have to watch my next 2 days closely to see if there is a correlation. So here's the story. Yesterday was my Weight + Cardio day, 30 minutes weights followed by 30 minutes on treadmill. When I started the treadmill, I was at an elevated heart rate, 150-152 BPM. The walk ended up with a 154 avgHR and burning about 500 calories. Today was cardio only, 60 minutes on the treadmill. I started out below my target range and it took several minutes to get up to the minimum 126 BPM. I ended up with a 137avgHR and rarely got to my anaerobic threshold (144 BPM). Only 750 calories burned. Both treadmill sessions were pretty much at the same intensity (based on distance).

I should have had a higher avgHR and burned more calories (1000 in an hour based on the 500 in an hour yesterday)

Has anyone else noticed this? It makes a little sense. I believe that weight training is mostly anaerobic and tends to stretch its effects after the activity is completed. It would make me think that the residual anaerobic weight training is adding to the aerobic treadmill?

The intention of anerobic is not to lose your breath while working out. That is a very simplified explanation of anerobic. It does mean lack of oxygen, but more on a muscular level. You will get the burn from lactic acid, the same sensation of lifting weights. That is all it is. However, when you get to that point you start producing growth hormone, which leads to serious fat burning. Lastly, aerobic, in regards to intervals, serves as your recovery to the anerobic portion of the interval.

My recommendation, ditch the monitoring your heart rate and target zones, and just do shorter periods (20-30 minutes) of interval training a couple of days a week and the one session on your treadmill for 30 or so minutes. Doing cardio all of the time is useless and actully halts any serious progress. Get creative. Get away from the same tired routine. Try and have fun. Doing this leads to a lifestyle change. When you are kept off guard and try new routines it keeps its luster, which means doing these kind of things longer. That is what separates those who are fit through life and those 5 oclock champions who fall off and on diets.