Some choices shape our future in ways we can’t immediately see. Wearable smart devices fall into that category. At first glance, they are insightful, motivational, convenient — and, in some cases, life-saving. Yet they are far more than gadgets strapped to our wrists or clipped to our clothes. They are extensions of our bodies, constantly transmitting data that reaches deep into our security, our safety, and our privacy.
This isn’t a guide to hacking smartwatches. It’s an exploration of three connected questions: what biological data wearables collect, how that data can put us at risk, and what practical steps we can take to stay in control.
The hidden depth of wearable data
Modern wearables have moved far beyond counting steps or estimating calorie burn. They now measure heart-rate variability, oxygen saturation, gait and posture, menstrual cycles, tremors, GPS location, and even environmental signals. Over time, these streams combine to form a “digital twin” — a detailed, real-time reflection of our body, emotions, behaviour, and location. This twin stays perfectly in sync with our physical reality for as long as the device is worn.
In some contexts, such as clinical care, disability support, aged care, or even space missions, this level of monitoring is invaluable. It can identify health issues before symptoms are felt and, in some cases, save lives. In commercial settings, wearable-based payments can be faster and more secure, particularly when combined with biometric checks.
But when we consider the sheer range of personal, biological, and behavioural information being recorded — and the number of third parties and governments it may reach — the potential risks become impossible to ignore.
Where the real risks lie
For major brands like Apple, Fitbit, Samsung, and leading medical device makers, the devices themselves are built to high security standards. Firmware is updated, MFA is available, and data is encrypted in transit. Breaking into the device directly is rarely the easiest route for attackers.
The greater risk sits elsewhere — in the centralised storage and ongoing sharing of that biological data. Many third-party integrations are designed to keep data flowing continuously, often prioritising uninterrupted access over user privacy. This makes the ecosystem an attractive target not only for cybercriminals but also for state actors with their own agendas.
Safety, access, and the personal map we didn’t mean to share
Think about a typical week: home, work, school drop-offs, gym sessions, maybe a stop at a defence base or a client site. Our wearables log those same routes with precision. In the wrong hands, that data becomes a playbook for tracking us or those we care about.
This risk is not theoretical. Location and health data from wearables has been misused in stalking and coercive control cases. Spoofed device signals have been used to unlock vehicles or gain access to secure areas. When the device is part of payment authentication, a compromise can affect both our finances and our physical safety.
When accounts become attack surfaces
The risk doesn’t stop at the device. If a third-party service linked to a wearable is breached, attackers could take over our account. That can mean being locked out of secure premises, having payments declined mid-journey, or losing critical health alerts. Manipulated sensor data can trigger false medical alarms — or suppress genuine ones — forcing decisions based on false information.
Profiling, exposure, and the long memory of data
Once data leaves the device, it rarely disappears. Wellness app data can find its way into insurance assessments, shaping hidden “shadow profiles” that influence coverage eligibility. Other seemingly unrelated data points — Wi-Fi logs, receipts, advertising identifiers — can re-link supposedly anonymous records back to us.
Over the years, these profiles can surface in unexpected contexts: as court evidence, during border checks, or after corporate mergers where data changes hands without our consent. The trigger for all of this is often a single acceptance of terms and conditions long forgotten.
The gap between what we think and what is
Many of us believe deleting a wearable’s companion app stops all data transfers. In reality, the flow often continues until permissions are revoked directly on the device. Because consent requests are frequent and usually designed for speed, we tend to approve them without much thought.
Most companies handling this data are not acting with malicious intent — for them, it’s about business. But our continuous biological feed is part of what keeps that business viable. While our ability to control the flow exists, it is often hidden behind obscure settings or limited by the business model itself. Acquisitions, changes in ownership, and international legal requests can all alter where our data goes and who can access it.
Taking back control with KCD
For some of us — those managing chronic illness, recovering from surgery, or caring for family — wearables are essential. For the rest, whether opting out is possible or not, maintaining awareness and control is critical. That’s where the KCD framework comes in:
Know what is being collected, where it’s sent, how long it’s stored, and how it can be deleted.
Control access by enabling MFA or passkeys, removing unsafe integrations, and revoking permissions both on the device and in companion apps.
Decide whether the benefits outweigh the risks — and avoid devices without clear revocation processes, transparent end-of-life policies, or trustworthy partners.
The choice is ours — and so is the cost
A wearable is more than a piece of consumer technology. It is a living dataset that touches our physical safety, our access to services, and even our legal standing. We decide what to connect, and we decide the price we are willing to pay. If we cannot know what it collects or control where it goes, we cannot fully protect ourselves.
The benefits are real — but so is the cost of ignoring the risks.
