Heart rate and calories burned

I'm currently using a website to calculate my calories burned. I use my average heart rate from the exercise bike for the calculator and input that data into MFP.

How accurate is this calories burned? I'm getting a net calorie burn of 704 on average with a 40 minute cycle. When I put 40 minutes into MFP it gives me 983 (I'm not sure if that's gross or net?)

It doesn't have to be perfect but I need to make sure it's accurate enough so that I'm still maintaining a healthy calorie deficit.

Replies

  • PPumpItUp
    PPumpItUp Posts: 208 Member
    Just use the exercise portion of MFP and input your exercise there.
  • callsitlikeiseeit
    callsitlikeiseeit Posts: 8,626 Member
    edited July 2015
    704 calories in 40 minute is HIGHLY unlikely. theres variables, of course... but that seems WAY out of whack. 400-500 would be VERY generous, imo.....
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
    Billy213 wrote: »
    How accurate is this calories burned? I'm getting a net calorie burn of 704 on average with a 40 minute cycle. When I put 40 minutes into MFP it gives me 983 (I'm not sure if that's gross or net?)

    Maybe half that on a good day. HR is only an indicator of calorie expenditure in a fairly limited set of circumstances.

    I'll get 400-500 cals cycling at 30kph for an hour on my turbo trainer.
  • TeaBea
    TeaBea Posts: 14,517 Member
    Most people who use MFP numbers will eat only 50-75% of exercise calories back. The numbers are notoriously generous.

    Calorie burns are very difficult to measure. Factors include: height, weight, age, gender, hormones, exertion level and more. The website is using your heart rate to estimate exertion....did you put in your resting heart rate so it can compare? BTW - using heart rate for strength training is pretty much worthless.
  • Billy213
    Billy213 Posts: 31 Member
    Well I'm averaging around 27km/h for 40 minutes with a 165bpm average heart rate. I'm 23, 6' 2" and 324lbs.

    Like I said, it hasnt got to perfect. Just enough to balance the books. The MFP numbers are definitely ridiculous. I'm not eating any of the calories back atm. 1. I don't trust the amount I'm burning. 2. I'm just not hungry enough to eat THAT much food.
  • TeaBea
    TeaBea Posts: 14,517 Member
    edited July 2015
    Billy213 wrote: »
    Well I'm averaging around 27km/h for 40 minutes with a 165bpm average heart rate. I'm 23, 6' 2" and 324lbs.

    Like I said, it hasnt got to perfect. Just enough to balance the books. The MFP numbers are definitely ridiculous. I'm not eating any of the calories back atm. 1. I don't trust the amount I'm burning. 2. I'm just not hungry enough to eat THAT much food.

    The estimator should compare your resting heart rate against something. Some people have a higher resting heart rate than others.

    If you are using MFP (as designed) you should be eating exercise calories back. MFP gave you a deficit before exercise, because not everyone can exercise. The reason for eating calories back, really large deficits make it hard for your body to support existing lean muscle mass. This becomes more and more important as you get closer to goal. It's probably okay for now.

    Hunger (or lack of) is not a good indicator of adequate nutrition. You body will use existing lean muscle for fuel if it has to. I keep a moderate deficit (closer to goal than you) because I want to lower my body fat percentage.
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
    Billy213 wrote: »
    Well I'm averaging around 27km/h for 40 minutes with a 165bpm average heart rate. I'm 23, 6' 2" and 324lbs.

    Like I said, it hasnt got to perfect. Just enough to balance the books. The MFP numbers are definitely ridiculous. I'm not eating any of the calories back atm. 1. I don't trust the amount I'm burning. 2. I'm just not hungry enough to eat THAT much food.

    Hour HR is significantly higher than I'd anticipate for that level of effort, that'll cause the over-read.
  • Billy213
    Billy213 Posts: 31 Member
    I just used another calculator using a resting heart rate VO2 and the calories burned came back fairly similar.

    9wwu6pqlguan.png

    That's what I've got for today, I've gone 240 calories into the extra calories earned. My deficit is my concern purely because the only calorie burn I have, I don't trust very much.

    This is my first week of using the bike and my second of logging food and eating healthy. I'd hate to eat too much to make up for an incorrect calorie deficit and then not be losing the weight I should.
  • Aussie_in_PA
    Aussie_in_PA Posts: 100 Member
    Like it was said, just use the MFP numbers...

    1) Every 2-3 weeks, average out your weekly weight loss
    2) adjust your MFP calorie targets up or down to keep a steady loss at 2-3lbs per week for your current weight
    3) repeat every 2-3 weeks.
  • WaterBunnie
    WaterBunnie Posts: 1,370 Member
    Time will tell. Takes me about 12 minutes to burn 100 calories on the gym bike doing speed intervals but the way you cycle, the effort you put in and your weight/build will all make a difference so nobody here can tell you what you are actually burning. To be safe I'd use the lower of the two estimates and eat your calories back and review whether you've lost what your deficit is set for after about 3 weeks. Not after just one week because you may carry more water weight in your healing muscles at first if it's new activity.
  • TeaBea
    TeaBea Posts: 14,517 Member
    edited July 2015
    Billy213 wrote: »
    I just used another calculator using a resting heart rate VO2 and the calories burned came back fairly similar.

    9wwu6pqlguan.png

    That's what I've got for today, I've gone 240 calories into the extra calories earned. My deficit is my concern purely because the only calorie burn I have, I don't trust very much.

    This is my first week of using the bike and my second of logging food and eating healthy. I'd hate to eat too much to make up for an incorrect calorie deficit and then not be losing the weight I should.

    This is good. Some people start with the most aggressive plan possible (1500 calories for men) and then eat no exercise calories back (scary). I wasn't sure where you started.
  • Billy213
    Billy213 Posts: 31 Member
    edited July 2015
    Like it was said, just use the MFP numbers...

    1) Every 2-3 weeks, average out your weekly weight loss
    2) adjust your MFP calorie targets up or down to keep a steady loss at 2-3lbs per week for your current weight
    3) repeat every 2-3 weeks.

    Okay that makes more sense. I'll base it from next weeks weight and go from there. Thanks all!

    TeaBea wrote: »
    This is good. Some people start with the most aggressive plan possible (1500 calories for men) and then eat no exercise calories back (scary). I wasn't sure where you started.

    Haha thankfully, no. I'm well aware of the importance of meeting my deficit. I have a lot of weight to lose but I'm not trying to do it overnight. I kept it a couple hundred under before I started exercising just to get the ball rolling and lost 11lbs in the first so I'm going in the right direction.
  • Aussie_in_PA
    Aussie_in_PA Posts: 100 Member
    Billy213 wrote: »
    Like it was said, just use the MFP numbers...

    1) Every 2-3 weeks, average out your weekly weight loss
    2) adjust your MFP calorie targets up or down to keep a steady loss at 2-3lbs per week for your current weight
    3) repeat every 2-3 weeks.

    Okay that makes more sense. I'll base it from next weeks weight and go from there. Thanks all!

    One example is what some have called the whoosh affect.. At its basics, a fat cell at 50% lipids, will pull in 50% water to make the cell full. 25% lipids, 75% water. As you reduce the lipids in that cell to zero from a caloric deficit (exercise or not), the water also dumps out of the cell. Sometimes I have had this happen and lost 8lbs in a week.

    Example for you
    Week 1: 324
    Week 2: 321 lbs -3
    Week 3: 320 lbs -1
    Week 4: 316 lbs -4

    Average 3 week loss = 2.6lbs.. Continue at current calories/net calories



    Another example for you
    Week 1: 324
    Week 2: 322 lbs -2
    Week 3: 320 lbs -2
    Week 4: 319 lbs -1

    Average 3 week loss = 1.6lbs.. and you want to be hitting 2 to 2.5 lbs. So you know you have roughly 3500 calorie surplus to remove. Review week's activities.. were you hurt, less workouts due to work etc... If it was normal, reduce MFP target by 500 calories per day and review again in 2-3 weeks to change.

    As you lose weight, caloric requirements come down generally (depending on lean mass blah blah and other things)
  • Billy213
    Billy213 Posts: 31 Member
    Time will tell. Takes me about 12 minutes to burn 100 calories on the gym bike doing speed intervals but the way you cycle, the effort you put in and your weight/build will all make a difference so nobody here can tell you what you are actually burning. To be safe I'd use the lower of the two estimates and eat your calories back and review whether you've lost what your deficit is set for after about 3 weeks. Not after just one week because you may carry more water weight in your healing muscles at first if it's new activity.

    Thanks WaterBunnie. The effort I'm putting in is quite high I feel. My bike goes from 1 to 15 and I use 9 and always try to maintain 80rpm. I'm going to try the varied difficulty programs soon and see how I fare with them.

    First day I managed 15km in 40 minutes, now I'm doing 18-19km in 40 minutes and maybe a couple rides a day depending on work commitments.
  • Billy213
    Billy213 Posts: 31 Member
    Average 3 week loss = 1.6lbs.. and you want to be hitting 2 to 2.5 lbs. So you know you have roughly 3500 calorie surplus to remove. Review week's activities.. were you hurt, less workouts due to work etc... If it was normal, reduce MFP target by 500 calories per day and review again in 2-3 weeks to change.

    As you lose weight, caloric requirements come down generally (depending on lean mass blah blah and other things)

    Thanks Aussie. That makes a lot of sense. I'm logging absolutely everything I eat and all the exercise so it should be fairly easy to get to grips with.

  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
    Billy213 wrote: »
    Well I'm averaging around 27km/h for 40 minutes with a 165bpm average heart rate. I'm 23, 6' 2" and 324lbs.

    The tricky bit with exercise bikes is the speed isn't real. Above 20kph, wind resistance on a road bike starts making a big difference - at your 17kph, it takes about 65W of power *just* for the pushback of the air. That's missing from the exercise bike.

    So where that distance on the road would be somewhere around 500-600 calories, unless you're on a pretty special exercise bike that knows to increase resistance exponentially with "speed", backing out the wind resistance power leaves you at somewhere around 200, 250-ish calories.
  • Billy213
    Billy213 Posts: 31 Member
    Mr_Knight wrote: »
    Billy213 wrote: »
    Well I'm averaging around 27km/h for 40 minutes with a 165bpm average heart rate. I'm 23, 6' 2" and 324lbs.

    The tricky bit with exercise bikes is the speed isn't real. Above 20kph, wind resistance on a road bike starts making a big difference - at your 17kph, it takes about 65W of power *just* for the pushback of the air. That's missing from the exercise bike.

    So where that distance on the road would be somewhere around 500-600 calories, unless you're on a pretty special exercise bike that knows to increase resistance exponentially with "speed", backing out the wind resistance power leaves you at somewhere around 200, 250-ish calories.

    This is very true. Wouldn't it all be relative though? If I cycled on a road for 40 minutes with wind resistance I wouldn't be cycling as fast or as hard as I am on the static. If I was doing 40 minutes at the same intensity as the static bike then yes, the calories would be very different.