Good point, and one that illustrates the point well. What you are referring to is the hypothesis that for a time, before projectiles were established, early humans may have used “persistence hunting”. This form of hunting actually takes advantage of the fact that moving more slowly is less costly than is sprinting. The idea behind it is that tracking and endurance running after prey, in very hot environments, could get the prey to engage in a series of costly sprints that they are are poorly equipped to recover from. The prey then collapses from heat exhaustion or is driven into a ravine. But that hypothesis still is proposing running for maybe 15 kilometers, not most of the time. Not “rare” but a still small portion of the day only in very hot environments. And of note the reason it is an attractive theory at all is particularly because running is so much less efficient for all animals but relatively less inefficient in heat for humans because we are able to run slowly and because we can dissipate heat better.
The question though was one of burning calories during the activity.
Well this bookends nicely with Otara’s comment. The whole fat burning zone concept is nonsense. Yes, staying in the aerobic zone will burn more fat during the activity, but if your goal is to lose fat you will do better to burn more calories be they immediately from glucose, glycogen, or fat. The fat will be burned later to provide energy and substrate while you build back up your glucose and glycogen stores. Moreover for the same calories burned high intensity interval training will result in more fat loss over time than lower intensity more prolonged exercise. (Something that always boggles the minds of those whose hang onto their Junior High School Physics class explanation of the First Law of Thermodynamics.)
A little tangential perhaps but it seems to fit in here, I lost half my body weight via eating less calories than I expended over a couple of years and then went and got myself diagnosed with lung disease, a side effect of which is in poorer quality air my heat rate leaps. According to a heart rate monitor a walk outside can raise my heart rate to 190 and it has been known to spike up to 234. Exercise indoors gives me more standard readings for someone my age (46) who has been exercising daily for 30 months and is pretty damned fit.
My question is can I trust the calorie burn estimates of my HRM? Is my inflated heart rate really impacting my calorie burn or are the equations going to be irrelevant with the lung complications? If I am really burning 13 -15 cal a minute going for a walk I need to get outside more, the best I seem to do inside is 10 and that is with sweating buckets and swearing included.
My doc knows about the spikes by the way, I am not seeking medical advice and I know that HRMs are not precise calorie estimating instruments but in general, does heartrate raised by environment mean more calories expended than the same activity in a non heart spiking environment?
An interesting question but one that is difficult to answer without speculating madly about the specifics of your particular lung disease.
My speculation is that in your case exercise in poorer quality air is triggering an airway reaction severe enough to result in low blood oxygen levels (hypoxia) and that the hypoxia is then causing your fast heart rate (tachycardia). Not a Good Thing and not reflective of total calorie burn.
The more general answer is that heart rate is just a proxy for your metabolic demands during exercise but can be misleading; increased metabolic demand (calories being burned) is not the only thing that can raise heart rate. Think of it this way: you might have a fast heart rate and breath heavy during an exciting part of a scary movie but you are not burning the calories you’d be burning from getting your heart rate to the same place by running hard.
That’s not really true. I mean, it’s not true that simple physics tells us that.
You have to be careful with the word “work” in this discussion because in the physical sense, there is no work done at all in moving a person from one location to another at the same elevation.
An energy analysis of the kind you have in mind would be applicable to a constant force problem such as raising weights, and would lead to a conclusion such as you stated above, but is not usefully applicable to this problem.
The simplest energy analysis of this problem (assuming no change in elevation) would take account of air resistance and rolling resistance (friction in the chain and wheel bearings, deforming the tyres, and so on). The former varies with speed and therefore the total energy input to the pedals over the length of the journey will vary with speed.
That is what I thought DSeid which is why I have never taken the calorie estimations seriously but I have been curious as I am trying to find a way to stabilise my weight at this point without dropping further. I was wondering if the gadget held the answer to the maths after all.
Just run of the mill boring as hell smoking created COPD, very well deserved in my case
