skysooner

My wife and I have both caught the exercise bug. She has been doing it for several years while I have been doing cardio for the last 6 months. Our chosen forms of exercise are different. I bike and job on occasion. She pretty much sticks to jogging on a treadmill. Here is a question from her:

She read on a website that she should not exceed 85% of her maximum heart rate for extended periods of time since supposedly the body starts to burn muscle. Based on a website for 35-40, she shouldn't exceed 156 beats/minute. When I exercise on the bike, I typically fluctuate between 124 and 145 depending upon how hard I'm working. When I job, I'm around 145 to 162 (again depending upon how I'm pushing myself. When she jogs, her heartrate gets up to 178 beats/minute sustained only doing 10 minute miles. Even though she has been doing this for 2 years and typically runs 5 miles/day, she got a bit concerned about this. She has had genetic hypertension in the past that was controlled through medication. Once she started exercising regularly, her blood pressure reduced to regular levels.

I guess her question is if this advice on not exceeding 85% of her maximum heart rate is correct, and if she is, would this affect her weight loss? She is 5'6" 127# or so. She has been down to around 122# in the past and really wants to lose those last 5 lbs. I tell her that some of it is due to building muscle mass due to weight lifting, but she is concerned that if the website is correct and if she is burning muscle that weight loss is not occurring the way it should. She eats a very healthy diet but somewhat low on calories (in my opinion anyway).