THE TREVITBLOG
Can You Really Trust a Smartwatch to Track Your Health?
Published: Wednesday, July 2, 2025
The Truth About What’s On Your Wrist
From tracking steps to pinging notifications, today’s smartwatches claim to be mini wellness coaches. But how accurate are they really? Can a wrist gadget truly measure your heart rate, stress levels, or sleep quality?
Let’s unpack the tech behind health tracking and see how devices like The Trevit Smartwatch turn raw data into meaningful wellness insights. Spoiler: it’s more science than you think.
Jump to section quickly:
How Smartwatches Monitor Your Health
Today’s wearables use a trio of components to track your health: sensors, movement tracking, and AI-powered algorithms.
- PPG Sensors: Measuring Your Pulse with Light
Smartwatches use photoplethysmography (PPG), which is a fancy way of saying they shine light into your skin and measure how blood absorbs and reflects it.- Green light is used for heart rate monitoring because it’s absorbed by red blood cells.
- Red/infrared light penetrates deeper and is better for SpO₂ (oxygen) readings.
These signals help estimate not only your heart rate but also oxygen saturation, blood pressure trends, and even stress levels.
- Motion Sensors & Sleep Stages
Built-in accelerometers monitor your body’s movements 24/7. During sleep:- Stillness = you’re likely asleep.
- Micro-movements + heart rate changes = REM, light, or deep sleep stages.
Together, motion and biometric data create a sleep profile more detailed than you’d expect from something on your wrist.
- Algorithms That Turn Signals into Insights
Here’s where your watch gets smart. With advanced algorithms, wearables interpret:
- Heart rate variability (HRV) to gauge stress
- Pulse transit time to estimate blood pressure trends
- Blood flow changes over time to model glucose estimates
- Metabolic Equivalent of Task (MET) to assess workout intensity
This combo of light, motion, and machine learning unlocks insights that were once only found in clinics.
Health Features: How They Work and How Reliable They Are
- Heart Rate Monitoring
Uses PPG light pulses to estimate beats per minute, accurate for rest and moderate activity, but motion may skew results slightly. Studies show wrist monitors are ~95% accurate in steady states. The Trevit Smartwatch’s dual-colour sensor enhances accuracy across skin tones.
- Blood Oxygen (SpO₂)
Red and infrared LEDs measure how much oxygen your red blood cells carry. It’s great for wellness tracking, though not a clinical tool.
- Stress (HRV-Based)
By analyzing the time between heartbeats, the watch estimates HRV. Lower HRV often means higher stress. It’s best used for trend tracking.
- Blood Pressure & Glucose (Study Mode)
These features combine PPG, motion, and timing data to estimate trends. They’re helpful for awareness, but not a substitute for medical devices.
- Sleep Tracking
Motion and heart rate changes help identify sleep stages. Stillness with low heart rate suggests deep sleep, while movement indicates lighter stages.
- MET (Metabolic Equivalent of Task)
This metric estimates calorie burn and workout intensity by comparing heart rate to movement.
Photos of The Trevit Smartwatch showing heart rate monitoring and MAI Vitality Score
How The Trevit Smartwatch Stands Out
The Trevit Smartwatch isn’t just another fitness tracker. It’s designed to give you a holistic wellness overview:
- Dual-colour 3-channel PPG sensor for more reliable readings
- Tracks heart rate, blood oxygen, stress, blood pressure (study mode), blood glucose (study mode), and sleep cycles
- One-tap access to a personalized MAI Vitality Score
What Is the MAI Vitality Score?
The MAI (Metabolic Activity Index) Vitality Score is your daily health snapshot. Think of it as a smart summary that bundles:
- Resting heart rate
- Sleep quality and duration
- HRV and stress patterns
- Activity levels and METs
- Blood oxygen trends
You get a single score that reflects how your body’s doing physically, mentally, and metabolically. It’s not just for tracking... it’s for improving.
What You Can and Can’t Trust
Smartwatches aren’t medical devices, but they’re getting impressively close. Here's a quick breakdown:
| Feature | Trust Level | Use It For |
|---|---|---|
| Heart Rate | ✅ Very reliable
| Everyday fitness, cardio zones |
| Blood Oxygen (SpO₂) | ✅ Reliable
| Wellness checks, altitude training |
| Stress (via HRV) | 👍 Directional
| Mood trends, relaxation reminders |
| Sleep Stages | 👍 Directional
| Habit tracking, sleep hygiene awareness |
| Blood Pressure / Glucose | 🔎 Trend-based
| Awareness, not diagnosis
|
| Feature | Trust Level | Use It For |
| Heart Rate | ✅ Very reliable
| Everyday fitness, cardio zones |
| Blood Oxygen (SpO₂) | ✅ Reliable
| Wellness checks, altitude training |
| Stress (via HRV) | 👍 Directional
| Mood trends, relaxation reminders |
| Sleep Stages | 👍 Directional
| Habit tracking, sleep hygiene awareness |
| Blood Pressure / Glucose | 🔎 Trend-based
| Awareness, not diagnosis
|
How to Use Your Smartwatch the Smart Way
- Morning: Check resting heart rate and oxygen levels
- Midday: Use HRV/stress cues to take mindful breaks
- Evening: Reflect on sleep quality and activity goals
- Weekly: Review your MAI score to see improvements or red flags
Pro tip: Trends matter more than single numbers. You're looking for consistency and positive momentum, not perfection.
Final Thoughts: Wear the Data, Don’t Worry It
Smartwatches won’t replace doctors, but they will help you know your body better. If you're using a device like The Trevit Smartwatch, you're already ahead of the game measuring what matters, setting smarter health goals, and getting feedback that helps you grow.
So yes, you can trust your smartwatch. Just don’t forget: the real power lies in how you respond to the data.
