Calibrating equipment for altitude

Friday, February 23rd, 2007

One of the experiments I was a guinea-pig for on the space station was a study into the correlation of heart rate and metabolism (energy expenditure) in space.

I didn’t have to do much – drink some amazingly expensive water (isotopically distinctive so it would make a good marker) and keep track of everything I ate. And wear a heart monitor, which recorded every beat for much of the flight. Apart from the irritation associated with the wiring of the heart monitor it was straightforward, all the hard work was done on the ground at the Sports Science Institute of South Africa, at UCT.

This was an extension of research they had been doing into the correlation of heart rate and metabolic activity in athletes, and they wanted to see if the same rules apply to astronauts in flight. Conclusions:

  1. Yes, they do.
  2. Astronauts don’t burn a lot of energy in space. Floating around is the ultimate couch potato profession, except for interesting events like EVA’s and decompression scenarios where every movement is against the pressurization of your suit.

I was reminded of all of this yesterday when I took a look at the readings of my heart rate monitor – just a low-end Polar heart strap and watch that I’ve been wearing out on the slopes for interest’s sake. The dear thing thinks I’ve been doing AMAZING amounts of exercise while snowboarding. In one day, apparently, I burned off 6,000 kcal, which is hardly likely given my very relaxed (“Sunday tripper”) approach to exercise in general.

I think the issue is that my heart rate is generally elevated when at altitude. The watch doesn’t know anything about altitude, though, so it thinks that I’m tearing up some imaginary track when really I’m enjoying a cup of vin chaud * at 3,000m.

So, does anybody know how to recalibrate one of these things, for a more realistic result? I’m guessing somebody has a data set which would allow one to normalize heart rate for altitude and body mass, and get better results. Or is there a monitor out there which senses altitude and takes it into account automatically?

* thanks to Pierre for pointing out that I’m not, in fact, drinking “lime wine”. What a limey I am.

13 Responses to “Calibrating equipment for altitude”

  1. Andreas Klostermann Says:


    At least the heart monitors I know (probably a lot cheaper and simpler than yours) calculate the energy consumption by selecting an activity and measuring the time. The heart rate actually has no direct correlation, at least not after an hour or so. A healthy individual can have 140 beats per minute not burning a lot more than at 90 , even though the heart certainly consumes more. At fitness centers they have Crosstrainers that can measure the “work” you are doing and derive the amount of calories you burn from that. Without measuring either the actual work of the muscle or the CO2 exhalation, it is quite impossible to arrive at a certain figure.

    So I’d suggest either recording the time you are actually on the slopes and finding some calorie-per-hour figure that matches your style, or take the nutritional aproach: Keep account of what you are eating, keep track of your weight and then you can make a guess of what you are actually burning during the day.

    Thanks for creating Ubuntu,

  2. Pierre Says:

    Hello Mark,

    well for your health’s sake, I suggest you not to drink any “vin chaux” as “chaux” means “lime” in French and I reckon it won’t do you no good 😉 … Obviously you meant “chaud”, which stands for “warm”.

    My computer wanted to add something to this little message : “thanks a lot for creating Ubuntu, now I have a good reason to start up every day !”


  3. Bob Says:

    Why isn’t launchpad free software? Do you want to control end-users like all the other proprietary software developers?

    Mark Shuttleworth says:

    No, Launchpad is proprietary because we use it to offer some services to companies who work with Ubuntu, and that helps to pay for the cost of developing both Launchpad and Ubuntu itself. With the XML-RPC interface under development you will be able to get every bit of your data out at any time, there’s no attempt to control anybody here.

  4. Martijn Dekkers Says:

    Depends on the model of the Polar you have – some can be recalibrated. From :

    Word of Caution about Heart Rates
    Many factors affect both your morning pulse and training pulse.
    • Stress (work, emotional, etc.) will increase your HR.
    • Nutrition, especially hydration levels, will also greatly influence your HR. Dehydration will skyrocket your HR.
    • Heat will also increase HR until your body adapts to it; usually 7 to 12 days.
    • Altitude will affect your HR as well. You will have a higher HR for the same level of intensity at higher elevations so give your body 3 weeks or so to adapt.

    I guess you are going to have to stay a bit longer on the slopes to get accurate readings – all in the name of science, of course…

  5. Andrew Says:

    You make an interesting point, and you do get HR monitors which do measure altitude (Polar S625X, RS800 and numerous others) although I’m not sure they take altitude into account though. I’m sure Tim Noakes has some ideas on the effect of altitude on HR, let me go and dig out “Lore of Running” and I’ll get back to you.

  6. Johan ¨Klei Lat¨ de Vries Says:

    Hello Mark,

    found your blog on the internet today, and have been reading most of the posts, and enjoying it.

    Just moved over to Ubuntu as well, so I am rather new to it, but have installed and running it without ant probs so far.

    We (myself and my daughter) make a Afrikaans podcast (wat n potgooi genoem word) from London every week, and if you around, (and have an hour or so to kill (I know they you are busy !) – would like to do an interview with you about Ubuntu.

  7. Danielle Says:

    You could always go with one of these:

    But this sounds more like what you’re looking for:

  8. Danny Says:

    I use my heart rate monitor while hiking in higher altitudes. Being a Florida guy, I live pretty much at sea level. When I go up as much as 2500 feet, my heart rate will increase for about 3 days. When I hiked in the Grand Tetons, I used my monitor to tell when I’d acclimated to the altitude. When I’m first in a higher altitude, I notice with almost any effort, my heart rate will quickly jump up, sometimes to as high as 185. When I stop the activity, it will drop to 80 within 30 seconds. I know I’m fairly acclimated to the altitude when my heart no longer jumps up with effort.

    The only way to make the caloric expenditure close to accurate, under any condition:
    1. Get your current body composition analyzed.
    2. Instead of entering your bodyweight in the Polar settings, enter your lean weight only.

    The idea here is that your lean weight uses energy, your fat stores energy.

    Now, if we could get some software for Polar in Ubuntu?

  9. A.G. Says:

    Hey Mark,

    Has Ubuntu reached a point where it can sustain itself? I mean, it can’t be cheap to develop such a wonderful O.S. and I would hate for all your funds to dry up working on Ubuntu (and I would hate for Ubuntu to end).

    Are there any plans in progress to increase revenue/profit for Ubuntu or are we all just holding tight hoping for current plans to eventually kick-in?

    Just a few questions from a happy Ubuntu user.

    (Sorry This is a bit off topic, but oh well.)

  10. Inez Says:

    Alpine pulse:

    I’d imagine that the fitter you become, and the more skilled at whatever it is you’re doing; your heart rate will correlate less and less with metabolic expenditure, as well as respond less briskly to moderate exercise. And the longer you stay at altitude, the more readily your expanding red cell mass will help you achieve effortless snowboarding and settle the tachycardia. However, the combination of wine and the little hot ski-suit will of course vasodilate the peripheries and may once again elevate the heart rate, without actually burning calories.

    Which may be sufficient reason to stick to the basics of weight, surface area, and distance travelled to calculate work of snowboarding [I’m reaching into the Standard 9 physics cortex with limited success]. The truly scientific approach may require attachment of spirometer, ECG monitor, pulse oximetry, BP cuff and temperature probe; all well beyond the scope of the simple altitude / heart rate converter and a day in the life of the occasional snowboarder. Such dedication to absolute scientific measurement may well propell you into the realms of the ridiculous.

    Console yourself with the possibility of leaving the Alps with the Haemoglobin to rival a Nepalese Sherpa.

  11. Lesley Clayton Says:

    I had the same experience of a higher heart rate and metabolism when I was in the Alps snowboarding recently. Extreme fear in the back of a taxi with a mad Italian driving at 170kph, altitude, exercise & adrenaline from snowboarding, temperature changes ( a week before I was the Kalahari desert) and a lot of visual stimulation in the form of gourgeous ski intructors! I still lost weight even though I was stuffing my face daily with pizza and pasta!

  12. wodnik92 Says:

    Hello Mr Mark!

    One loses his health when beeing in space due to lack of gravity. You can’t change that even if you train a lot. One could say that you get older very, very fast. Anyway — this is not what I wanted to tell you.

    Please consider free energy generators in our civilization. Imagine vacuum cleaner, cell phone, TV that you don’t have to plug into wall… Plase imagine magnetic engines that don’t have to be filled with fuel.

    Here is the summary of free energy generators:
    And here is about that magnetic engines:

    Thank you for reading.
    wodnik92, totalizm supporter

  13. Yolandé Says:

    Hi Mark,
    Polar monitors are outdated – You should get yourself a Garmin Forerunner 305 – It’s a very funky all in one watch mainly for runners, well which you don’t like doing..but..skiing will be fine too! Although there will be disadvantages as well of course, it’s the “forerunner” at the moment in every way. It’s very light and sexy, has the same functionalities as the polar monitor, but it has a GPS system as well. Check the garmin website. (haha – I sound like a sales agent!) I’m buying one at the moment. You can download your whole journey, and surely that info can be used to rework your true energy loss & heart rate. Sport Science Institute or the clever scientists replying should have some complicated formulae to do that – if they can!