William M. Briggs

Statistician to the Stars!

Extremely fit have larger carbon footprints than do couch potatoes: scientific study

The following is a scientific study:

Extremely fit have larger carbon footprints than do couch potatoes


Dr H. Harrister, BS, MS, PhD, OBWAG


Ever since the Supreme Court has (wisely) ruled that carbon dioxide is a pollutant, the number of people who have been made exceptionally nervous has increased nearly exponentially (exponentially is a mathematical term). It is up to science to discover ways of reducing this vile gas, to root out its sources, and suggest interesting ways of scientifically punishing environmental malefactors.

Thus, it follows that it is the duty of every single person to reduce their carbon footprint in every conceivable way, and to do so in the shortest amount of time humanely possible before disaster strikes.

The purpose of this scientific paper, therefore, is to bring to mind a particular activity that had previously been assumed virtuous but under the unerring eye of science has proved to be pernicious. That activity is exercise.


We accept, as we must accept after the highest court in the land said so, that carbon dioxide (CO2) is a pollutant. Many common people—unfortunately, those without sufficient educations—are not aware that each time they exhale they are adding to the excessive burden of CO2 in our precious atmosphere. This is because humans inhale oxygen into their lungs with each breath—oxygen that is forever depleted from the air, because that oxygen is processed into CO2.

Each exhaled breath contains a certain amount of CO2. The exact amount is a function of total lung capacity, residual lung volume, and vital capacity, as well as related to other measures of pulmonary function. In this paper, we make the reasonable approximation that variations in the amount of CO2 exhaled per breath are negligible, that is, the amount of exhaled CO2 is fixed for all people, except in two ways which we note below. It is important to recognize, however, that most of this human CO2 outgassing takes place in the troposphere (troposphere is a meteorological term), in the boundary layer. Shockingly, this is also where most people live.

The main source of variation of exhaled pollution (CO2), the intra-person variability, is due to respiration rate (RR). Higher RRs mean more breaths per hour and therefore more pollution added to the atmosphere, and therefore the more likely we are to experience runaway greenhouse effects. Therefore, people with lower RRs have smaller carbon footprints (or lungprints as we should properly say) than those people with higher RRs.

Let LS = lung size. The average resting breath for an adult North American human male contains about LSrest = 325 ml of air. This expands to twice this under aerobic stress (exercise), to about LSstress = 650 ml of air. There will be variations in these values, of course, but we scientifically dispense with this uncertainty.

Because all tissue in the human body has to be oxygenated lest it turn sour, it implies that the fatter (larger) a person is the more oxygen they consume. This is mitigated somewhat because those at that highest scale of fatness, the couch potatoes, tend to engage in very little movement. And since movement means using muscles, and muscles rely on oxygen as part of their fuel, less movement means less oxygen usage (or utilization, if you prefer).

Since the humans under our consideration are assigned to have equal lung volume and other pulmonary functions, more oxygen usage is equivalent to higher RRs. As explained above, more oxygen usage is directly proportional to more CO2 creation. To be explicit: higher RRs give rise to higher amounts of CO2 degassing to the atmosphere. Not all of the air inhaled in processed into CO2. Let the fraction of each breath that is converted to pollutants be fco2.

The RR of couch potatoes is likely to be even and vary little throughout any 24-hour period because of their habit of remaining as stationary as possible. This rate will be slightly higher than thin, non exercising people, and higher than exercising people at rest because couch potatoes’ larger bodies need more oxygen. Studies have shown that this rate is RRCP = 14 breaths per minute. Thus, we present equation 1, the amount of pollutant added (PA) to the atmosphere per day for this class of individual:

Eq. 1    PACP = RRCP x LSrest x fco2 x 60 minutes hours-1 x 24 hours day-1

This equation is unlikely to be wrong because it has been written in the proper mathematical format. It also uses scientific notation, and your author has a PhD.

Equation 1 can be contrasted to a similar equation for those who engage in excessive exercise, which is defined as 22 hours of calm followed by two hours (not necessarily contiguous) of frenetic bursts of ludicrous activity. The RR for exercisers at rest is known to be RREx:rest = 12 breaths per minute. While engaged in stressful activities this rises to RREx:stress = 30 breaths per minute. Thus, the daily amount of PA for exercisers is

Eq. 2    PAEx = RREx:rest x LSrest x fco2 x 60 minutes hours-1 x 22 hours day-1 + RREx:stress x LSstress x fco2 x 120 minutes

Substituting the precise values into equations 1 and 2 gives

Eq. 1b    PACP = 14 x 325 x fco2 x 60 x 24 hours

which equals

Eq. 1c    PACP = 6552000 x fco2


Eq. 2b    PAEx = 12 x 325 x fco2 x 60 minutes hours-1 x 22 hours day-1 + 30 x 650 x fco2 x 120 minutes

which equals

Eq. 2c    PAEx = 5148000 x fco2 + 2340000 x fco2 = 7488000 x fco2

which makes the ratio of PAEx to PACP equal to

Eq. 3    PAEx/PACP = 1.142857

Conveniently, we do not need to know the exact value of fco2, as it cancels in the equation.


Through the strictest scientific procedures, the same as those used in a myriad of studies of this type, we have conclusively proven that those people who exercise have a carbon foot (or lung) print 14.29% higher than those who, altruistically it turns out, lie around on the couch. Future studies will examine the additional benefits of progressing to a drunken stupor, a state in which minimal oxygen usage is obtained.

It might be argued that CPs eat more, thus they increase the amount of CO2 added because of their increased food intake. But this argument is specious when contrasted with the habits of the very fit, defined as people who typically motor to Whole Foods in their SUVs to buy only “organic” comestibles, the creation of which produces far more CO2 than does, say, manufacturing bags of Cheesy Puffs, the chosen snack food of most couch potatoes. Plus, of course, those who exercise more actual consume a greater amount of food than do lazy slobs (this is scientifically true).

The policy implications of this study are obvious: people must be discouraged immediately from exercising. They should be taught the immorality of it, how their narcissistic habits unnecessarily add to carbon burden of the atmosphere, thus endangering the fragile climate system, and therefore the future for our children.

If we can each stop just one jogger from donning his multi-colored, garish shorts and trotting through the neighborhood, we will have done the Earth a tremendous service.

Editor’s note: please help disseminate this scientific study as widely as possible. Inform journalists of the perilous and frightening nature of its conclusions. The time to act is now.


  1. With my academic connection, I was able to obtain the following referee report on this article.

    Dr. Harrister has presented impressive, rigorous calculations (though nonsense) that undoubtedly only a PhD (and a notable OBWAG, whatever it is) can manipulate. Her/his implication that exercise is no “greener” than watching TV due to its CO2 production is mind-boggling. The potential of stirring up controversy and the diverting humor of great entertaining value in this paper have prompted me to recommend acceptance of this paper.

    As a formality I would like to remind authors to please follow carefully the instructions in the Author’s Guide. The Reference Section is obviously missing for no reason! ^_^

  2. One could add that couch potato are efficient carbon storage device. They fill themselves and when they die, they are put into the ground.

    Maybe we should fill up these people in the third world, they certainly don’t lack the capacity.

  3. I suspected as much – add this to the body of evidence that shows that walking to the supermarket is less environmentally-friendly than driving….


    Obvious really that walking should have a heavier carbon “footprint” ….

  4. Excellent work, fit for publication in the finest climate science journals. Maybe the next step is to do some regression analysis between the increasing amount of total exercise done (starting perhaps with the running boom of the 80’s) and temperature changes. It would probably have a high correlation coefficient so it has to be true that more exercise causes warming. Anyone who doesn’t think so is a Denier funded by Big Oil!

  5. Great study! To further this line of research, food types more condusive to other greenhouse gases, eg. methane, need investigation.

  6. Hansen wants the CEOs of Big Sneakers to be put on trial for crimes on the running trails.

  7. I’m giving up celery in protest. I suggest all concerned citizens do the same.

  8. I endeavored to determine what a OBWAG is. An extensive Google search disclosed on the first page of results two promising links:


    Unfortunately, the former got me into a loop and the second is all Greek to me. The next step is to write a computer program that takes all the “O’ words in a dictionary and combine them with all the B, W, A, and G words, I will post the results.

    I am rather fond of the Tour de France, though my enjoyment has diminished since I heard that the racers burn some 5,000 to 6,000 calories per day, more than a ill-trained human body can digest per day. Perhaps an appropriate offset is to teach CPs how to watch a bicycle stage race and get them hooked on watching, not doing.

  9. Mmmmmm! Cheezy Puffs. I’ve been vindicated.

  10. Ric Werme
    obstetrics, womens health and gynecology

  11. Following on from the above, I have said many times that it can be clearly shown that shortly before death, everyone who dies was breathing. Therefore it follows that breathing is very bad for you and the sooner everyone like Dr. Harrister stops breathing, the better off the rest of us will be.

    In a similar vein, Penn & Teller have a lot of fun in this


  12. Rick,

    It seems google was right after this site contain the answer. Nothing is faster than Google.

  13. WB,

    On separate topic, I would be interested in hearing your views on yesterday’s WSJ article claiming flawed statistical analysis by Boston Scientific:

    Will we be seeing a post from you on this topic?

  14. This means that the USA having the highest rate of over weight and obese people is actually the nation where a higher rate of people are producing less co2 than either fit or regular people.

    I think they deserve a few carbon credits for this.

  15. For every Big Mac McDonald sells, and for each pound Americans gain, the threat of global warming goes down a little.

    Can’t deny it now.

    It is scientific.

    And I’m only half joking…

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