I am a former personal trainer (thinking of getting re-certified). I like to combine heart rate with RPE, or Rate of Perceived Exertion. An RPE of 1 would be like laying in bed. A 10 would be, "I can't sustain this more than a few seconds/gonna die." Shooting for somewhere around a 6-7 ("This is definitely got my heart pumpin, but I could do it for a while") is a great place to be. You should also be able to carry on a conversation with short phrases. I've found that after a few weeks of practicing this, I can almost guess what my heart rate will be based on how my body feels. If I started getting up to an 8 or 9, I begin to feel a bit woozy and short of breath, so I slow down. If I'm not sweating and can carry on a full conversation, I'm probably at a 3 or 4 and need to pick up the pace.

The great thing about RPE is that it really helps you get in tune with your body. On days where my allergies are acting up or I'm not feeling well, my RPE will be higher - my body is telling me to take it easy. On days that I'm feeling great, I can push my body a bit more.

Good for you for getting to the gym!

Thanks so much everyone for all the input!!!

I am basically working as hard as I can sustain now...interestingly though, my jaunt at the gym yesterday had the heart rate sensors staying a fair bit lower. Averaging in the 150's. I'm sure 2 trips to the gym (not including yesterday) didn't cause that, so they must be a bit inaccurate.

I only use 1 treadmill at the gym because I tried another and the tread was slipping/skipping, so I think I may just be too heavy for it. There are 2 that are the same make/model, and one that's a newer nautilus (which is the one I use).

I refuse to give up.

Today is a day off, but I will do some light stretching (cause I am soooo sore LOL), and lift a few light weights (just have 2lb and 3lb dumb bells) to try and limber up a bit, and to not be too slack!