HRM calories

Options
blondeheat
blondeheat Posts: 254 Member
in Fitness and Exercise
Anyone know how accurate the calories on HRM are? I have been eating all my calories and exercising everyday using the calories measure on HRM. I have felt pretty drained and low on energy during some of my long bike rides (I even used sports drink). These rides are 2 - 3 hrs long with avg HR of 155. In the past 4 days, I have lost 2 lbs (yeah!), but my goal is 1 lbs per week! Is the HRM under estimating calories?

Replies

  • blondeheat
    blondeheat Posts: 254 Member
    Options
    Anyone know how accurate the calories on HRM are? I have been eating all my calories and exercising everyday using the calories measure on HRM. I have felt pretty drained and low on energy during some of my long bike rides (I even used sports drink). These rides are 2 - 3 hrs long with avg HR of 155. In the past 4 days, I have lost 2 lbs (yeah!), but my goal is 1 lbs per week! Is the HRM under estimating calories?
  • laurenk182004
    laurenk182004 Posts: 1,882 Member
    Options
    I have also lost 4 lbs this week and haven't done anything differently, maybe it's just your body catching up to all the hard work you've been doing! I have heard that the HRM are pretty accurate, but it probably depends on which one u have. I say if u feel drained like that maybe u need more protein? just a thought! :)
  • lotusfromthemud
    lotusfromthemud Posts: 5,335 Member
    Options
    It depends on the HRM. Those are some long bike rides, maybe find one of the "power gels" (like a sports nutrition bar, but liquid for the road) to perk you up.

    What is the HRM saying you burn on one of these rides?
  • banks1850
    banks1850 Posts: 3,475 Member
    Options
    If you're feeling drained, I would attribute that more likely to not having the right types of food then not enough. If your going carb light for a 2 to 3 hour bike ride, then yeah, you're gonna feel drained. Remember, the body isn't nearly as efficient at converting fat to energy as it is converting carbohydrates. Using fat as energy is a 4 step process where as carbs are a 2 step. I.E. for fat the body has to grab the fat, transfer it to the place where fat is converted, break down the fat, and transfer the energy. Where as carbs it just has to break down the carbs and transfer it.
  • shorerider
    shorerider Posts: 3,817 Member
    Options
    Yeah, what does your HRM say you're burning? I ride, too, but am heavier than you. Right now, I ride every day for at least 40 minutes. I keep my heart rate in the 70-80% range and burn anywhere from 320 to 380 for that ride.
  • blondeheat
    blondeheat Posts: 254 Member
    Options
    Thanks for your replies!

    The 2.5 hour ride last night was 1000 calories according to HRM.

    I ate a pasta dish b4, a bottle of sports drink (180 cals), one gu (90 cals) during.

    I am not doing a carb restricted diet as I totally bonked on my bike rides with South Beach!
  • banks1850
    banks1850 Posts: 3,475 Member
    Options
    Thanks for your replies!

    The 2.5 hour ride last night was 1000 calories according to HRM.

    I ate a pasta dish b4, a bottle of sports drink (180 cals), one gu (90 cals) during.

    I am not doing a carb restricted diet as I totally bonked on my bike rides with South Beach!

    mmm, I don't necessarily agree, both pasta and sports drinks are refined suger, unless it is whole wheat pasta. They travel through your body extremely fast. I doubt the carbs in pasta last more then an hour, and the sports drinks? even faster because they are basically just sugar in it's most basic form. I would question whether either one lasts in your body for longer then an hour or so.
  • shorerider
    shorerider Posts: 3,817 Member
    Options
    I agree-depending on the pasta and how much you ate. Plus, you didn't mention if you're eating your exercise calories every day, too. How many total calories are you eating a day?
  • blondeheat
    blondeheat Posts: 254 Member
    Options
    I am eating 1200 calories plus whatever I exercise. I estimate at the beginning of the day what my evening exercise will be so I don't exercise then eat the calories but try to put them in especially lunch, afternoon snack and pre ride food.

    I am trying to figure out the best way to deal with a large variation in exercise - some days I run for 30 min, cycle for 1- 3 hours, do a Power class (weight lifting to music), walk for 1 hour, swim for 40 min, belly dance for 1 hour.

    As you can see, my calories burned for exercise can vary from 300-400 range to 1000-2000 or more as I start to do 4 hour bike rides.
  • shorerider
    shorerider Posts: 3,817 Member
    Options
    Not knowing more specifics here but 1200 calories to me seems too much a deficit for you given the small amount of weight that you wish to lose. You might want to evaluate your goals and up your daily basic intake. Especially considering your level of activity! 1200 calories seems way too low to me for what you're doing every day and amount you have to lose.
  • lizard9800
    lizard9800 Posts: 474 Member
    Options
    I have gone on 60-90 minute bike rides and burned between 500-700 calories according to my HRM, so 1000 for 2.5 hours seems fine to me. I usually eat a power bar about half way through and drink a lot of water. Whole grain bagels/cereal will give long lasting energy and bananas are great too.
  • banks1850
    banks1850 Posts: 3,475 Member
    Options
    I guess all I can say is if you're only trying to lose 15 then try to keep your deficit somewhere between 250 cals and 500 a day. I know this can be tough, but more then that I don't think your body will accept as healthy. Especially considering how active you are. The other thing to remember is this site trends towards underestimating your maintenance calories for healthy people. You might want to check what your actual maintenance calories are (wear your HRM for a full day, sleeping included, but don't work out, just do normal daily stuff). If it's higher then you thought, then you found your answer.
  • blondeheat
    blondeheat Posts: 254 Member
    Options
    I found this info on a bicycling website, which also partially answers my question!

    http://www.velonews.com/article/9116

    When heart rate monitor is used to measure energy expenditure, it is based on a linear relationship between heart rate and oxygen consumption that exists for each person. However, the same heart rate may not correspond to the same level of oxygen consumption in each person, and there is individual variability, so it is only estimation. When you input your weight into the heart rate monitor and estimate your max heart rate, this results in only an estimate of the calories burned based on a one size fits all equation.

    And a good article in NY Times on calories burned
    http://www.nytimes.com/2007/12/20/health/nutrition/20BEST.html?_r=1&adxnnl=1&oref=slogin&adxnnlx=1210951412-eqzlb36Zj9/Q7uMYFdwGqQ

    I think you are right banks, I choose "sendentary" as my job is sitting at a desk. But even a work, I get up more than the people around me and at home, I never watch TV. I probably should change that setting to get a few more calories per day.

Categories