Modern activity trackers take their roots from the Ancient Greco-Roman world and the odometer, (from Ancient Greek, hodós ‘path, way’ and métron ‘measure’) a device for measuring the distance travelled by a vehicle by recording the number of spins of its wheels.
And while DaVinci is known for making sketches of an odometer designed to measure the distance walked by a person, yet not reaching any further, a French craftsman, Jean Jernel is believed to have invented the first wearable device to measure the distance walked by its owner when in 1525 designed a watch that: “comprised a system of toothed wheels and pinions driven by the movement of a kind of swinging lever, which turned needles round the faces of four dials which successively counted units, tens, hundreds and thousands” (Errard de Bar‑le‑Duc , 1584).
The first description in English of “An instrument called a waywiser, by the motion whereof a man may see how many steps he takes in a-day” was recorded in 1679, in a personal diary, whereas the first definition of a watch pedometer comes from 1728 Ephraim Chambers’ Cyclopædia; or a Universal Dictionary of Arts and Sciences: “Pedometer, or Podometer, or Way-wiser, a mechanical instrument, in form of a watch; consisting of various wheels….which by means of a chain or string fastened to a man’s foot, or a wheel of a chariot, advance a notch each step or each revolution of the wheel…”
It is the Swiss horologist Abraham-Louis Perrelet to be officially recognised as the inventor of the pedometer-wind watch, worn in the pocket and self-winding just by the walking movement of the wearer, to later, in 1780, expand the mechanism to measure the steps and distance walked.
Several years later, Thomas Jefferson introduced the American public to the pedometer (discovering it while on a trip in France), which mechanism is well-described in a letter he sent to James Madison on May 3, 1788: “I send your pedometer. … cut a little hole in the bottom of your left watch pocket, pass the hook and tape through it, and down between the breeches and drawers, and fix the hook on the edge of your knee band, an inch from the knee buckle; then hook the instrument itself by its swivel hook, on the upper edge of the watch pocket. Your tape being well adjusted in length, your double steps will be exactly counted by the instrument, the shortest hand pointing out the thousands, the flat hand the hundreds, and the long hand the tens and units …”
The so-called Tomish meters evolved into less-complex wearable devices, to be fairly popular only among long-distance walkers, and by the 1930s marketed as Hike-o-meters to be worn attached to the ankle.
A real fitness-related breakthrough came in 1965, when a Japanese professor concluded that a 10,000-daily step regime is the target to achieve optimum weight control and fitness (the meaning of state of being physically fit is from 1935) and his research well-fitted into a marketing campaign for a Japanese company that had made a pedometer called Manpo-kei, Japanese for 10,000 (man), steps (po) and measure (kei).
The first wireless heart rate monitor, the Polar Sport Tester PE 2000, was released in 1982 and Fitbit, which debuted in 2008 as a clip-on device, is considered to be the first activity trackers to garner mainstream attention.
In the last 10 years, the fitness tracking and wearables industry has significantly skyrocketed, and while consumers are surrounded by a plethora of fitness tracking apps and wearable options to track their activity level and monitor health, and at the least try to keep up with the recommended 10k daily steps, the size of the global wearable fitness trackers market is forecasted to generate a revenue of EUR 42 billion by 2023.