This glossary defines the terms you will see on almost every fitness tracker in India, from HRV and SpO2 to IP68 and PPG, in plain language rather than spec-sheet shorthand. Each entry links to a full guide if you want to go deeper.
HRV (Heart Rate Variability)
The tiny variation in time between one heartbeat and the next. It sounds like noise, but it is actually a useful signal: more variation generally means your body is relaxed and recovered; less variation generally means it is under some kind of strain, physical or otherwise. Full guide: What Is HRV in a Fitness Tracker?
SpO2 (Blood Oxygen)
An estimate of how much of your blood's oxygen-carrying capacity is in use right now, usually shown as a percentage. Most healthy adults at sea level sit around 95 to 100 percent. Full guide: What is SpO2?
PPG (Photoplethysmography)
The sensor technology behind most of this. A small light on the back of your tracker shines into your wrist, and the sensor reads how that light bounces back as blood moves through your skin with each heartbeat. Heart rate, SpO2, and blood pressure trend estimates all come from this one sensor. Full guide: What Is a PPG Sensor?
IP68
A water and dust resistance rating. The first digit (6) covers dust, the second (8) covers water beyond a basic splash rating. In practice, IP68 devices are generally fine for sweat, rain, and showering.
GPS-connected tracking
Route and distance tracking that uses your phone's GPS rather than a chip built into the tracker itself. It works well as long as you carry your phone during the activity.
Sport modes
Pre-set activity profiles (for running, cycling, gym sessions and so on) that a tracker uses to log a session with the right kind of data for that activity.
Blood pressure trend tracking
An estimate of systolic and diastolic pressure calculated from the wrist pulse signal. It is useful for watching a trend over weeks, not as a replacement for a validated arm cuff or a clinical reading. Full guide: How Fitness Trackers Monitor Blood Pressure
Stress tracking
A score derived mainly from heart rate and HRV, meant to show how strained your body seems compared with your own normal. It cannot read your emotions and is not a medical measurement. Full guide: Can a Fitness Tracker Help You Manage Stress?
Screenless tracker
A fitness band with no display at all. You check your data in a phone app rather than on your wrist. The trade-off is usually a longer battery life and a slimmer, lighter band. Full guide: Screenless Fitness Tracker: Is a No-Screen Health Band the Smarter Choice?
Companion app
The phone app a tracker connects to over Bluetooth to show your data. Qorfit Pulse uses the free QWatch Pro app on Android and iOS, with no subscription required.
Wellness tracker (as opposed to a medical device)
A device designed to give you general health awareness and trends, not a clinically certified diagnostic instrument. This distinction matters: a wellness tracker can flag a pattern worth discussing with a doctor, but it cannot diagnose anything on its own.
