When I go to log in to the website managed by the maker of my sports watch, I get a vivid sense of how many people are doing the same thing. A counter – like the one that shows the rising national debt – displays a torrent of tumbling figures as people with the same brand of sports watch as mine clock up miles of running or biking. The total stands at 1.85bn miles – or, as the site helpfully informs me, not quite 4,000 trips to the moon and back. Given all the times I've gone running or cycling and forgotten to start my watch and log the workout, I reckon we could claim that 4,000.

But it's not the miles that mean anything; mere miles are dumb. All those people with such sports watchs are also keeping track of their GPS-located routes, their pace and time, their calorie-burn, their heart-rate telemetry, and so on. A good proportion of those people could also give you decent working definitions of interval training, lactic threshold, the ATP system, VO2max and so on. A few years ago, these concepts belonged to an obscure priesthood of people with PhDs in human physiology. Nowadays, it's the lingua franca of the fitness coaching page in one of the recreational running or cycling magazine or any of the glossy health and fitness titles that promise "awesome abs" in five minutes a day.

Thanks to an information revolution over the past decade, a formerly arcane, laboratory-based field of human knowledge has passed into the realm of popular science. We are all exercise physiologists now.

I've watched this happen in several ways. In the mainstream media, blogs and columns have started up, which rely on culling titbits from academic research journals, translating and interpreting their findings for a lay reader. Among my bookmarks, for instance, are the excellent SweatScience and the New York Times's Phys Ed blog. Judging by how often the latter's articles ended up on the NYT's "most emailed" list, I'm not on my own.

One of my favourite examples of this breakthrough in the mass dissemination of specialist knowledge was the now famous 2009 paper presented at the American College of Sports Medicine annual meeting that found that chocolate milk is better at promoting athletic performance than pricey, purpose-made energy drinks. Not that this message seems to have quenched the marketing success of "scientifically" designed sports nutrition drinks.

At the serious end of the fitness fiend market, it's become routine for ambitious triathletes, runners and cyclists to subscribe to the services of a coach, either in person or via online correspondence. Training goals are set, workouts meticulously recorded, and performance monitored.

The technology enabling the analysis of all these individual workouts is constantly evolving: the GPS-enabled sports watches get cheaper, apps for smart phones mimic what they do, "democratising" the data-collection still further. Devices like power-meters, which precisely measure a cyclist's output in watts, were just a few years ago the preserve of professional athletes; now, they're commonplace among weekend warriors.

And finally, as a consequence of the boom in public demand for knowledge of athletic potential and performance, the hard science itself has become a sexy field. Suddenly, it is awash with research grants for all kinds of niche projects – about, say, how exactly your muscle cell mitochondria react when saturated with hydrogen ions – in order to feed the burgeoning academic journal publishing business, which in turn provides fodder for the popular blogs and newspaper columns.

For example, if, five or six years ago, you had wanted a VO2max test (the gold standard of aerobic fitness attainment, which measures how much oxygen your cardiovascular system can transport and use in a given time), you would have to pay a laboratory a three-figure fee to endure a horrible "ramp" test, aka "test to exhaustion", to get that number. Nowadays, it's common for researchers to advertise on cyclists' and runners' forums, seeking guinea pigs to hook up in their labs with electrodes.

Human subjects, of course, are not necessary for all studies. Consequently, there are also a lot of very fit rodents in labs these days – which gives a new, literal meaning to the expression "gym rats". I guess, from a mouse's point of view, a life on a treadmill beats cancer research.

Animal welfare concerns aside, though, what could possibly be wrong with extending the breadth and depth of human knowledge? It may not be opera or poetry, but it's useful, valuable even. Especially where health and fitness are concerned, is it not simply an unqualified good that more people know more exercise science?

Yes, and no. In practical terms, I would want to ask who, for instance, is getting the most value from this boom in sports science? Are its benefits evenly distributed? But there is a philosophical dimension also. As with any epistemological event, we should look behind the claims to the value-neutrality of pure science, and examine the ideology implicit in the "new knowledge". In this case: the proposition that there is an unlimited potential of athletic performance that can be realised with the correct scientific tools has at its kernel the idea of human perfectibility.

The quest for the body beautiful has many noble aspects: an Apollonian dream that can claim a heritage from Plato, through the Renaissance, to the Enlightenment and Modernism. But its fantasy of humanity's godlike self-actualisation also brought us, variously, racial "science" and eugenics, Leni Riefenstahl's ode to Hitler's Olympics, Ayn Rand's Nietzschean elite and so on.

Do I seriously see the spectre of fascism in contemporary exercise science? No, that would be ahistorical: eugenics-based racial "science" was specifically the nightmare flip side of the mid-20th century's fantasy of human perfectibility.

Every age gets the science it deserves, in the sense that its scientific interests and knowledge reflect the larger preoccupations, ideological themes and social conflicts of a given epoch. Twenty-first century western society is characterised by a growing gap between rich and poor, with power distributed ever more oligarchically by the market's "invisible hand", to the detriment of increasingly dysfunctional and hollow institutions of formal democracy. Since that is the larger context for the new sports science, which is our version of the perfectability trope, what we risk is a dichotomy between the super-fit 1% and the morbidly unhealthy 99%.

On one side of exercise science's epistemological divide, a fabulously toned elite is getting a perfect balance of carbs, protein and minerals, washed down with potassium-rich "natural" coconut milk in cartons that cost about the same as the hourly minimum wage, which fuels a daily personal trainer-coached session of high-intensity interval training. At 60 plus, the members of this exercise elite still have the body that 99% of the population stopped seeing in the mirror in their teens. Existential reality for the latter is survival against a backdrop of declining real income, indebtedness, time-crunched family life, and heavily marketed, mass-produced instant gratification dietary options.

For the majority of people, better health would be worth having; fitness is a luxury few can afford. To her credit, Phys Ed columnist Gretchen Reynolds implicitly recognises the problematic of privilege and inequality in her new book, with a self-explanatory title that is getting a great deal of play: The First 20 Minutes: Surprising Science Reveals How We Can Exercise Better, Train Smart, Live Longer. The attempted populism of her message is that the science tells us that you only need to get up off the couch and walk around for 20 minutes to be healthy; you don't need to work our harder than that to get most of the benefits of exercise. It's an admirable impulse, but will it by itself bridge the gap between society's skinny perfectionists and the broad mass of people?

The new sports science is not to blame for our society's inequalities of health and fitness, but it is a register of them, however we prefer to see our science as value-free and neutral. The dream of human perfectibility always has a strong and unattractive strand of self-congratulation. It is marvelous to be a perfect specimen of scientific fitness; in many ways, it is its own reward. But it is also good to recognise the inherent risk in those swelling feelings of superiority and bear in mind that inquiring into the conditions that produce society's fitness-"havenots" may be more useful application of knowledge.