So, last night I went to the gym for a trial run. However, I have some concerns.

There were a few posters up around the gym with "target heart rate" info, so I was trying to stay within the target heart rate for my age, but I found that my work out ended up not being very intense...if I felt like a had a good work out going, my heart rate was too high (165 or so).

I didn't know what the consequences for "exceeding" my target heart rate were, and was afraid to blow up my heart LOL.

What's the best way to work out at the gym when you're just starting out?

go by how you feel... if you felt fine at 165, than thats ok...... target HR's, just like BMRs and calories burned ad everything else are just a pace to start...to give a "general" guideline... everyone is different, everyones HEART is different (stronger/weaker) lung capacity, you name it. If you felt good, than you were ok. Your heart wont BLOW up if you go above your target rate

When I joined my very first gym (Dec 2001) I would only do 10 mins on the elliptical and (according to the machine) my HR would go up to 200+. My heart didn't blow up... i was just in HORRIBLE shape at the time.

Even now that I am SO much better than I was then - My HR is still up around 170 - 180 when I am jogging along. If I try to push myself to run a bit faster/harder it will go up past 180. If I tried to keep my HR at 130 or what ever the charts say- I would never improve.

Just LISTEN to your body. Don't hurt yourself. If it hurts, stop. If it doesn't - keep goin'.

The "less healthy" you are the higher your heart rate is. When I first started working out my heart rate exceeded 200! It freaked me out also. Your max heart rate is supposed to be 220 - your age. So for me it's supposed to be 192 at max when I work out (they say 85% of the max is good which would put me at 163). Now my heart rate when I work out is in the 160s because I've lost weight and changed my habits. I continued to work out even when I was in the low 200s because I didn't feel pain and I knew exercise was beneficial. As you lose weight that number will go down- so don't hold back UNLESS you are feeling pain.

Thank you all so much! I feel like I jipped myself of a decent work out because I was worried about going past that target rate. I'm sure I would easily hit 180 or 190 if I had really applied myself. I am in terribly shape, I have led a sedentary life, and I'm quite overweight, so past is where we will go.

I watch a lot of those weight loss shows (X-weighted, Heavy, etc) because I find them inspiring, and wondered if they worried about target heart rates, etc, since the work outs seemed so intense. I suppose not!

I can only echo what everyone else has said. I use perceived exertion and only amuse myself with the HR stuff on the machines. They're incredibly inaccurate anyway. My resting HR is always around 50 but the moment I hop onto a machine it already has me at 100, right off the bat. I'm not sure it goes lower than 100.

I too started out in the very high range. I worried about it, but I found that the more effort I put in, ignoring the HR, the faster those numbers came down. I got the biggest kick out of the numbers. Soon I learned what my perceived effort felt like for each level and I amused myself endlessly as day by day the numbers stopped going up so high. And my BP came down right along with it.

The charts are definitely a generalization. Most people use the %max method, that you and the other posters are talking about but the ACSM teaches a much more accurate method that takes your individual resting heart rate into consideration. This is the Karvonen method. I dont know your stats so i'll just show you mine and you can do this on your own Take your resting heart rate before you get out of bed in the morning to get the most accurate reading. Whenever you calculate your target heart rate for exercise, you need a range, not just a number.
220-20=200bpm (my max heart rate)
55-(My resting heart rate; RHR)
200-55(RHR)=145 (my heart rate reserve; HRR)
145*.65=94.25+55(RHR)=149.25 bpm (the low end of my range, 65%)
145*.85=123.25+55(RHR)=178.25 bpm (the high end of my range, 85%)

So when I do cardio, my personal target heart rate range is 149.25-178.25 bpm.
When deciding on your precentages that you want to work out at, be honest with yourself and your fitness level. I workout everyday so 65-85% is okay for me but someone who doesnt feel they are as fit or is just starting out is much safer working their heart at about 50-70%.
If you workout at too high of a percentage, your body begins to work anaerobically instead of aerobically and cannot sustain this high of an intensity.
As for your, whats the best way to workout question..thats a whole larger topic and it comes down to preference more than anything.
If you have any other questions feel free to ask. I'm a health sciences major and i'm about to sit for my personal training certification and I can talk about exercise for hours haha

... and so you slow down or back off. It fixes itself.

Well yes and no...Theres a small range of intensity in the anaerobic zone that is sustainable before you reach your VO2max. This range of intensity is for very hardcore training (the opposite of what people want when theyre first starting to exercise.) Most people would slow down or back off in this zone because they can't go on but staying out of that zone completely would be much more effective.
More lactic acid is produced at this intensity and for the purposes the OP was asking about, the ACSM advises against training in this zone.

If your post was refering to something else please let me know, as your post wasnt very clear.

Here is my situation...

I am 36 years old, weigh 287 lbs, and have a resting heart rate of around 96 (omg...that's so bad...that's just sitting here right now). I am finding that I am comfortable exercising to about 165-170 bmp (as per the machines)...although apparently 157 is the upper most in my target heart rate. I feel like I am getting a work out at 165, while I feel like I have to hold back to maintain the 157. If I wanted to maintain the 157 I couldn't set foot on the elliptical because it really gets my heart racing.

Is it wrong of me to work in the 165-170 bmp range? Am I overdoing it there?

According to the machine you're definitely working out really hard! lol
You said the machine is giving you this reading, correct? Have you used a personal heart rate monitor? I only say this because the reading on the machines can get kinda funky....sometimes when I'm in the midst of the endurance phase of my workout and i'm going all out I get a reading of like 87 which is just not possible. Sometimes it gives me a really high reading just during my warmup.
Also, I'm not a doctor or anything but according to the ACSM your resting heart rate is fairly high. Did you get that reading after drinking coffee or something else with caffeine or had you been moving around a lot? If your heart rate is just naturally high than that might explain why your heart rate jumps so high during exercise. Cardio strengthens the heart so not only will your blood pressure improve, but your resting heart rate will go down too.

When I am on the machine I don't pay attention to the target heart rate any longer. It seems that it is never right. I find it better to just go all out and then before I get off take the time to recover. Once I changed this I saw a lot more progress in my weight loss.

Also, the gym is the best place to have your heart blow up... all of the trainers are probably CPR certified and they probably have a defibrilator too. LOL!

I've noticed that when I'm sweating a lot, the cardio equip at the gym fluctuates with the heart rate a lot, or sometimes doesn't give me a reading. I don't worry too much about it. Your own perception of how hard you're working and how hard you should be working is accurate. Also, if you're a new member of your gym, ask if they have an orientation session- that can be SUPER helpful to get information, start a routine, and ask some general questions.

haha @stacygee...so true! At least you know people can take care of you if you do get overworked!
and same djs06! Its like the sweat blocks the receptors or something...but if youre working hard/sweating then who really needs the reading anyway? lol

just wanted to add (if it hasn't been stated) that when your HR is elevated do not simply STOP when you feel you've reached your point. Your body needs to slowly and steadily decrease your HR (walking at a slow pace works for me). My trainer always says that you can pass out if you go from a high HR to just suddenly stopping.

BTW, I thought it was cute what you said about being concerned that your heart would blow up