Using Heart Rate monitor...where should I have my heart rate

I recently got a heart rate monitor & have a question. I gone to see a fitness instructor at the gym & he said it'd be better to do a work out on exercise machines really hard, about 80-85% of my max heart rate. But then I read in most other places I should work out at around 50%. The fitness instructor said which while I will not be burning off as much fat during the wortkout, that afterwards my metabolism will be higher after the workout so in the end I will be burning more calories.
What is the go, should I be training at say 50-60% of my max heart rate which dosent really wear me out in an hour, or should I train at
80-85%

My goal at the moment really is to loose weight,

Neither. The so-occasionally called fat-burning zone is largely a legend, but it exists at around 70%, not at 50%, & not at 85%.

The easiest way to say if you are in this zone is the simple runner's test - can you carry on a conversation? If you can, but not by a whole lot, you are in the zone. If you can converse easaily, you are below it, and if you cannot talk, you're above it.

Workin out at 50% is not good for much except using up calories, but for me, that level of effort just makes me hunghry and I end up fervently gaining weight. There is ample evidence to sugest that exercising above the zone at least some of the time is a very good thing, and exercising at
90-100% for short bursdts has also been proven to be effecvtive.

-S- http://www.kbnj.com