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The device on your wrist is the latest chapter in a story that began with a Japanese walking club in the mid-1960s. From a mechanical clip-on step counter to a smart ring that tracks heart rhythm and overnight temperature, each generation solved one problem and created the expectations that shaped the next. This is how a simple curiosity became a health monitoring platform worn by hundreds of millions of people.
Manpo-kei: The First Mass-Market Step Counter
The story usually starts in 1965, when Japanese researchers and a watch company introduced the manpo-kei, or “10,000-step meter,” riding the fitness enthusiasm around the 1964 Tokyo Olympics. The device was a simple mechanical pedometer marketed to a walking club, and the round number stuck: it became the default daily goal decades before any wearable could verify it. Early pedometers counted steps with a spring-loaded pendulum that clicked when the wearer’s hip moved, which meant they missed subtle steps and overcounted bumps — limitations that persist in modern algorithms, as our explainer on why step counts differ across devices shows.
Through the 1970s and 1980s, pedometers remained a niche product sold to walkers and runners. They recorded a single number, reset each morning, and offered no memory, connectivity, or context. Yet the core idea — quantify movement, then change behavior — was already in place. Modern trackers like those reviewed in our guide to step counters that transform daily movement are direct descendants of the manpo-kei.
1970s Calculator Watches and Digital Wrists
The first electronic watches appeared in the early 1970s, and by the middle of the decade several companies were selling calculator watches — digital timepieces with tiny keypads for arithmetic. They were not health devices, but they established something important: people would wear a computer on the wrist if it did something a pocket device could not. The category also proved that watch form factors could absorb new functions without becoming unwearable, an argument every later wearable maker would reuse.
The 1980s added pulse sensors to sports watches aimed at runners and aerobic exercisers. Those first heart rate monitors used chest straps rather than optical sensors; wrist-based optical measurement, the technology inside most modern devices, did not reach consumer products until much later. If you want to understand how far that sensor has come, our breakdown of how smartwatch heart rate sensors work traces the path from green LEDs to medical-grade estimates.
The 2000s: Bluetooth, Phone Clips, and Wireless Data
Bluetooth arrived in 1999, and by the mid-2000s it was reshaping accessories. Wireless headsets, heart rate straps, and early activity monitors could finally stream data to phones and computers without cables, and the phone became the dashboard. GPS watches for runners appeared around 2003, moving positioning from bulky handheld units to the wrist and turning pace, distance, and route into everyday numbers.
Wearable cameras and fitness-focused Bluetooth accessories crowded the decade as well. Most were single-purpose: a step counter counted steps, a heart rate strap measured heart rate, and virtually nothing talked to anything else. That fragmentation set up the next shift — a device that combined sensors, software, and a social layer in one package.
Fitbit, 2007, and the Quantified Self
When Fitbit launched in 2007, the context mattered as much as the hardware. The quantified self movement was gaining momentum, smartphones had put sensors in everyone’s pocket, and social media had made sharing personal data normal. Fitbit’s clip-on tracker measured steps, distance, calories, and sleep, then synced wirelessly to a web dashboard where users could compare streaks with friends. The step count became a social object.
Competitors followed quickly — Jawbone’s UP band, Nike’s FuelBand, and a wave of budget pedometers — and the industry learned that behavior change, not measurement alone, was the product. Sleep tracking moved from a lab to the bedside, and the term “activity tracker” entered the mainstream vocabulary.
Pebble, Crowdfunding, and the Smartwatch Boom
The smartwatch era arrived in 2012 when Pebble raised more than $10 million on Kickstarter, an early proof that crowdfunding could launch hardware at scale. Pebble watches displayed phone notifications, ran third-party apps, and lasted about a week on a charge — a battery benchmark that still embarrasses many premium watches. Competitors including Samsung, Sony, and Motorola released their own smartwatches, and Android Wear brought a common platform to the category.
The boom exposed the central tension of wearable design: capabilities versus battery life. Devices that added color screens and sensors lost runtime; those that prioritized longevity gave up functionality. That trade-off still shapes the market, and it is part of why battery claims remain so difficult to compare, as we explain in our article on why smartwatch battery ratings are misleading.
Apple Watch and the Pivot to Health
Apple Watch arrived in 2015 and reframed the smartwatch from a notification accessory into a health device. The first generation included an optical heart rate sensor; later models added GPS, water resistance, fall detection, and, in 2018, an ECG app that recorded a single-lead rhythm and could flag atrial fibrillation. That FDA-cleared feature changed how regulators and consumers thought about wrist wearables. Our guide to ECG and AFib detection covers what the technology can and cannot diagnose.
Blood oxygen sensing arrived in 2020, giving wrist wearables a second clinical-adjacent metric — with important limitations, as we detail in our explanation of blood oxygen sensors. Skin temperature followed, built around overnight baselines rather than absolute readings. Within a decade, the smartwatch had become a multi-sensor platform rather than a wrist computer.
Sensor Milestones: Heart Rate, ECG, SpO2, Temperature
The Sensor Stack Expands
Each sensor generation widened the definition of a wearable:
- Optical heart rate (2010s). Green and red LEDs plus photodiodes made all-day heart rate practical without a chest strap.
- GPS and multi-constellation positioning. Watches moved from single-system GPS to combined GPS, GLONASS, Galileo, and BeiDou for faster, more reliable locks — a shift we unpack in GPS vs GLONASS vs Galileo.
- ECG (2018 onward). Single-lead recordings brought arrhythmia screening to the wrist, with regulatory clearance in some markets.
- SpO2 (2020 onward). Pulse oximetry joined sleep and altitude tracking, though accuracy varies by device and conditions.
- Skin temperature (2020s). Overnight deviation tracking opened the door to cycle, illness, and recovery insights, as covered in our article on skin temperature sensors.
From Gadget to Monitoring Platform
Together these sensors turned the wrist into a continuous monitoring site — not a hospital, but far more than a pedometer.
Smart Rings, CGMs, and the Invisible Wearable
The newest wave pushes hardware off the wrist entirely. Smart rings such as Oura, Ultrahuman, and the Samsung Galaxy Ring pack heart rate, temperature, and motion sensors into a few grams of titanium, trading screen space for comfort and battery life. Continuous glucose monitors, once reserved for diabetes care, now attract metabolic-health consumers, and the overlap between rings, CGMs, and watches is producing a layered personal health stack. Our guide to choosing health tracking rings covers what to look for in this fast-moving category.
Where Wearables Go Next
The next decade will likely be defined less by new sensors than by better interpretation. Expect tighter integration between wrist devices, rings, and skin patches; more regulatory clearance for screening features; and algorithms that detect health changes earlier in populations rather than individuals. Battery technology, sensor miniaturization, and privacy regulation will decide which promises survive contact with the market. The pedometer’s descendants will keep counting steps — but the question they answer is no longer how far you walked. It is how your body is doing.
Frequently Asked Questions
When was the first wearable step counter invented?
The manpo-kei went on sale in 1965 in Japan, designed around the 10,000-step concept promoted during the 1964 Tokyo Olympics. Mechanical pedometers existed earlier in various forms, but the manpo-kei was the first device to turn step counting into a mass-market health habit.
Did smartwatches exist before the Apple Watch?
Yes. Early digital watches with extra functions appeared in the 1970s, and modern notification-based smartwatches arrived in the early 2010s from Pebble, Samsung, Sony, and others. Apple Watch, released in 2015, pushed the category toward health features.
Why did Pebble matter to the smartwatch industry?
Pebble’s 2012 Kickstarter campaign proved that crowdfunding could launch a consumer hardware product at scale. It also set expectations for week-long battery life, app support, and always-on displays that later premium watches struggled to match.
When did heart rate tracking move to the wrist?
Chest straps dominated for decades, and reliable wrist-based optical heart rate only became common in the 2010s. The technology uses light rather than electrical signals, which makes it convenient but more sensitive to motion and fit.
What was the first health feature cleared by regulators on a smartwatch?
The ECG app on Apple Watch Series 4, released in 2018, was cleared by the FDA to record a single-lead electrocardiogram and flag signs of atrial fibrillation. It marked the moment wrist wearables crossed from fitness gadgets into regulated health tools.
Are smart rings newer than smartwatches?
Yes, as a mainstream category. Prototype and novelty rings appeared earlier, but consumer smart rings such as Oura reached broad adoption only in the 2010s and 2020s, after smartwatch sensors had already proven the underlying technology.
What will wearables track next?
The likeliest advances are in interpretation rather than brand-new sensors: earlier illness detection, blood pressure, non-invasive glucose monitoring, and tighter integration between watches, rings, and clinical systems. Regulatory clearance and battery life will shape how quickly these arrive.