Does one's burn rate change with pace? One calculator says yes.

fishgutzy
fishgutzy Posts: 2,807 Member
edited April 2016 in Social Groups
I did a little experiment based on a comment made in a thread.
I use the web site http://42.195km.net/e/swim/ to calculate calories burned for several distances while keeping the time constant at 60 minutes.
Total calories goes up in a linear relationship with distance. However kcal burn rate goes down.
So someone who takes 60 minute to swim 1000m will burn fewer calories than someone swimming 4500m in the same time, but will burn at a higher rate.
The assumption in the calculator seems to be that if one is swimming faster, one's efficiency gain overcomes that increased resistance force due to faster movement through the water.
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Replies

  • emmab0902
    emmab0902 Posts: 2,338 Member
    Interesting - that gives me about a 10% higher calorie burn than using MFP fast vigorous based on 1.30/100m.
  • rosebarnalice
    rosebarnalice Posts: 3,488 Member
    Even though I swim at what I consider a "moderate to intense" pace, I log my workouts as "light to moderate" because I think the calories burned that MFP credits me for it too much otherwise
  • girlwithcurls2
    girlwithcurls2 Posts: 2,281 Member
    I log all of mine as "light to moderate" even though I know when I'm pushing more. I do know that when I was swimming with less efficiency, it took a lot more out of me, making me feel like I burned more. It makes sense.
  • nuffer
    nuffer Posts: 402 Member
    I think in order to get past the "light/moderate" MFP is looking for a pace that's somewhere around 1:30/hundred yards. Can't remember where I saw that, though. When I started in the pool last year, I'd log half the time as light/moderate and half as fast/vigorous but I stopped doing that after I saw that delineation. My PR for 100 yds in a workout is 1:45 so I don't know if I will ever get to that pace.
  • emmab0902
    emmab0902 Posts: 2,338 Member
    I just take an average of 1.30 per 100m. Even though some sets will be more like 1.20 or faster, I drop it down to 1.30 to cover the slower bits like kick or other strokes.
  • gentlygently
    gentlygently Posts: 752 Member
    My PR of 59 secs per 50m is looking so sad...(!)

    Still, I go a lot faster than lots of people in my pool. (And like you Curly, in the early days I am quite sure my calorie burn was higher. )

  • girlwithcurls2
    girlwithcurls2 Posts: 2,281 Member
    Gently, we should share a lane!! I'm at about 1:00 for 50yards. Yesterday, I was doing kick sets with fins, so much faster than my usual swim, but I was circling with three other people who I could tell would have been perfect for my usual swim pace. Made me bummed that I couldn't join with my arms yet. It's not often that you get that ideal circle of people going.
  • NoelFigart1
    NoelFigart1 Posts: 1,276 Member
    Eh, I swim slower than the lot of you! 2:39 per 100y and I'm a happy camper. (All I can say is that it's down from 3:02/100, so my missing is getting closer)
  • Robertus
    Robertus Posts: 558 Member
    Speed and calorie-burn are only partially related to efficiency. All other things being equal, a relatively inefficient swimmer will expend more calories when swimming at the same speed as a more efficient swimmer. This is one of the reasons why swimming can be such a great exercise even for beginners if they swim at a sustainable rate. This is a problem with all swim calorie calculators. They do not factor in any measure for efficiency. The only true measure of calories burned is long-term measures of weight loss. I found the calorie burn estimates of the MyFitnessPal swimming calculator to be amazingly accurate over 3 months of meticulous food and exercise logging, which suggests that I may be a less efficient swimmer than those of you who say it overestimates your calorie-burn!
  • gentlygently
    gentlygently Posts: 752 Member
    Nope Noel you are faster than me ... That was my PR sprint time. I can only join curly for the laps I am sprinting. (Sorry Curly, it would have been nice!)

    Usually I am really slow by you guys standard - 3.5 mins per 100 averaged across the whole session (which always includes my snail pace breast, drills etc). Checked back my notes and my fastest crawl only was 2.8 per 100 (timed across 1K session). That was January of last year. I haven't bothered to time it since.

    My goals are more about doing it all than getting faster I guess. I have to 'start again' a lot. Hey ho. Bodies eh. Lots of people in my situation don't make it to the pool at all, and don't get to feel pretty fit like I do.

    Quite agree Robertus. I imagine, now I am a lot more efficient, but not a lot faster - my calorie is as unimpressive as my Speed. But, swimming still makes me fitter and more able to eat cake without dire consequences. If the cake eating gets out of control I will have to go bad to realy bad technique swimming just to compensate.

    I guess they don't do an 'at least you stick with but your speeds/distances are not being very impressive' award - do they?!
  • fishgutzy
    fishgutzy Posts: 2,807 Member
    nuffer wrote: »
    I think in order to get past the "light/moderate" MFP is looking for a pace that's somewhere around 1:30/hundred yards. Can't remember where I saw that, though. When I started in the pool last year, I'd log half the time as light/moderate and half as fast/vigorous but I stopped doing that after I saw that delineation. My PR for 100 yds in a workout is 1:45 so I don't know if I will ever get to that pace.

    Actually, the light moderate assumes 50 yards per minute. The faster option assumes 75 yards per minute. I found a Web site that uses the same calculator and payed the assumptions.
    I do about 55 seconds per 50 and just log 1 minute per lap.
  • AquaticQuests
    AquaticQuests Posts: 947 Member
    Robertus wrote: »
    Speed and calorie-burn are only partially related to efficiency. All other things being equal, a relatively inefficient swimmer will expend more calories when swimming at the same speed as a more efficient swimmer. This is one of the reasons why swimming can be such a great exercise even for beginners if they swim at a sustainable rate. This is a problem with all swim calorie calculators. They do not factor in any measure for efficiency. The only true measure of calories burned is long-term measures of weight loss. I found the calorie burn estimates of the MyFitnessPal swimming calculator to be amazingly accurate over 3 months of meticulous food and exercise logging, which suggests that I may be a less efficient swimmer than those of you who say it overestimates your calorie-burn!

    True! For example a perfect calculator would take into account stroke rate! I can swim the same distance, at the same pace at different stroke rates, and I assure you the burn is much higher at the higher stroke rate, which of course means the efficiency was less at the higher stroke rate!

    So distance and pace are really good indicators (and probably the best we can hope for from a calculator), but factoring in stroke rate and heart rate would probably yield an even more accurate result!

    But to throw a spanner in the works, research seems to show that as the body gets used to exercise, it burns les calories from the same exercise. So even if I weighed today, exactly what I did same time last year, and had consistently been swimming 2.5 km 4 or 5 times a week at the exact same pace, my body is likely burning less calories today, then it was burning if I swam the same distance a year ago, at the same pace, at the same weight! Bummer :disappointed:
  • fishgutzy
    fishgutzy Posts: 2,807 Member
    And that is why I use the basic MFP k cal estimate. Too many variables to get really accurate for each person. My pace is around 55 seconds per lap. So the 1 minute per lap assumption works fine. Other calculators spit out a higher kcal burned. I'd rather err on the lower side.