Your Reflex Active smartwatch does more than just count your steps: it keeps track of your health in real time. One of the most popular features across our smartwatch collections is heart rate monitoring.
But have you ever wondered how your watch actually measures your pulse without any wires or chest straps? Let’s look at the clever technology behind it: and how to get the most accurate readings possible.
Smartwatches measure heart rate using a technology called photoplethysmography, or PPG for short. It sounds complex, but the principle is surprisingly simple.
On the underside of your watch, you’ll notice tiny green LED lights. These shine light onto your skin, and sensors beside them detect how much light is reflected back. Because blood absorbs light differently as it flows through your veins, your watch can detect the tiny changes that occur with every heartbeat. By analysing these fluctuations, your Reflex Active smartwatch calculates your beats per minute (BPM).
It’s a completely non-invasive, light-based measurement; which means you can monitor your heart rate comfortably throughout the day, whether you’re working, resting or exercising.
Most heart rate sensors use green LEDs because green light is absorbed well by red blood (which contains oxygen). This makes it easier to detect the pulse signal from the wrist. Some high-end wearables also use infrared light for low-power, continuous monitoring, especially during sleep, but green LEDs remain the most responsive for daytime activity.
For best results, your smartwatch should sit snugly against your wrist, about one finger above your wrist bone. It shouldn’t feel tight, but it should stay in place when you move. Dirt, moisture, tattoos, or even very loose fitting can affect how well the light reflects into your skin: so it’s worth cleaning the back of your watch regularly and ensuring the strap is secure.
During workouts, a slightly tighter fit helps keep the sensor stable, reducing noise from wrist movement. Afterwards, you can loosen it again for comfort.
Temperature can also influence readings. Cold skin may cause blood flow to slow slightly, which can lead to lower or delayed heart rate readings. If you’ve just stepped outside on a chilly morning, give your watch a few minutes to warm up with you before checking your BPM.
Many Reflex Active models offer both continuous and on-demand heart rate tracking. Continuous monitoring measures your pulse at regular intervals throughout the day, giving you a complete picture of how your heart rate changes during rest, activity, and recovery.
On-demand tracking, on the other hand, lets you take a manual reading whenever you choose: perfect for spot checks during exercise or relaxation. You can view your data instantly on your watch, or dive deeper into trends and averages in the Reflex Active Red or Reflex Active Bluecompanion app.
Your heart rate can reveal a lot about your overall wellbeing. A consistently lower resting heart rate can indicate good cardiovascular fitness, while sudden increases during normal activities might signal stress, dehydration, or fatigue.
Monitoring trends over time helps you understand how your body responds to exercise, rest, and lifestyle changes. For example, if your resting heart rate is lower after regular workouts or improved sleep, it’s a good sign that your health is moving in the right direction.
Whether you’re wearing a classic model like the Series 12 or a vibrant Series 54 AMOLED, every Reflex Active smartwatch is designed with user comfort and accuracy in mind. Each model uses optical sensors to continuously collect reliable data: all displayed clearly on the watch screen or through the app.
You can explore the full Reflex Active smartwatch range to find a model that fits your style, from sporty designs to sleek everyday wear.
If your readings seem unusually high or low, it’s worth checking that your watch is positioned correctly and your skin is clean. Make sure you’re wearing it in good contact with the skin and that the latest firmware is installed. For troubleshooting steps, visit the Reflex Active Support Centre.
Heart rate tracking is more than just numbers: it’s a window into how your body performs, recovers and adapts. Your Reflex Active smartwatch gives you an easy, everyday way to stay connected with your wellbeing, helping you make informed choices about exercise, rest and lifestyle.
So next time you glance at your wrist to check your pulse, you’ll know exactly how your watch is capturing that data: with light, precision, and a little bit of science working quietly behind the scenes.
