Circular Ring 2 tracks your activity across low, medium, and high intensity zones, estimates your calorie burn from real effort, and connects it with your sleep, recovery, and HRV, so you know whether to push, adjust, or recover today.
Order Circular Ring 2You train, you track, you check the app. The numbers go up and down but nothing really changes. You don't know if you should push harder or pull back. You can't tell if yesterday's session helped or hurt. And after a while, the data starts to feel like noise.
Your calorie burn and intensity zones are right there on the screen. But the app stops there. What you actually do tomorrow is still your problem to figure out.
A hard training day means nothing if you cannot see how it lands on your sleep, HRV, and energy the next morning.
Most platforms charge a monthly fee to unlock the deeper data layer that turns activity data into real results.
Circular Ring 2 reads your activity like a coach. Heart rate and movement together, intensity scored against your own maximum heart rate, all of it read alongside your sleep and recovery. Push, recover, adjust. And it counts your whole day's calorie burn, not just your workout, so you always know where you stand.
Kira AI reads your activity, your recovery, your sleep, and your HRV, then writes one specific thing to do today for better results.
Low, medium, and high intensity zones built on your personal Maximum Heart Rate, not a generic benchmark.
Calories estimated from movement, heart rate, and activity context, not steps alone.
Your day's effort is never read in isolation. It is interpreted alongside how your body recovered overnight.
Kira AI calibrates to your body over your first two weeks, then keeps learning. The system reads your data against your own normal, not a population average.
Activity intensity, calorie burn tracking, and Kira AI's actionable insights are all included with your ring's free 14+ core feature plan.
Your legs feel heavy walking down the stairs. You open the app and see what your body already told you. HRV dropped overnight, sleep ran light, and yesterday's high intensity time was higher than you remembered. Kira AI suggests going easy today and you follow her advice.
You did not train. You crossed the office, ran errands, took the stairs more than once. By evening you are wrecked and cannot say why. The graph shows most of your afternoon in the medium zone. You did train. Just not the way you thought.
You finish an hour sure you did something serious. The breakdown says mostly medium, with a few short pushes into high. Kira says the soreness is real but the load is lighter than it feels, so tomorrow's session stays on the calendar. You almost cancelled it.
The last five days, almost nothing hit medium intensity. Not deliberate rest. Just life getting busy and the gym falling off the list. A short brisk walk today brings the week back into balance. You make time after lunch.
You ride for forty minutes. The ring catches the effort, but logging it as a session gives you a cleaner calorie estimate and a clearer picture of where the ride sits in your day. Tomorrow's recommendation reads it properly because you did.
Three hard days in a row. Recovery is dropping. Energy is sliding. You feel it before you see it, but the data backs it up. Kira AI says take it easy tomorrow. Your body would have made the same call, just a day or two later, when it would be harder to recover from.
You feel flat by three and have no idea why. No workout, normal food, enough sleep. The report shows most of your morning in the medium zone without you noticing. Kira ties it back to the day you actually had. An earlier night would help.
A calorie burn tracker shows you the calories you burned. Kira AI tells you what to do next.
Kira AI reads your activity intensity zones, calorie burn, sport sessions, and daily movement against your sleep, recovery, stress, and HRV. Every morning, it translates what your body actually did yesterday into one clear thing to do today for better results. Push, or pull back. Add a session, or take the easy walk. Adjust your bedtime. The answer is built on your personal baseline, not a generic recommendation.
You do not get raw data. You get a coach.
The ring tracks activity using accelerometer data, heart rate, and heart rate variability. These signals are read together to classify intensity zones, estimate calories burned, and detect movement patterns across the day.
Intensity is measured as a percentage of your maximum heart rate, personalised to your age, gender, fitness level, and your own baseline.
Low intensity: 40 to 55% of your Maximum Heart Rate. Easy movement like walking, stretching, shopping, or light dancing. Breathing stays normal.
Medium intensity: 55 to 75% of your Maximum Heart Rate. Brisk walking, jogging, flat cycling, or steady endurance work. Breathing gets deeper, with light sweat after about ten minutes.
High intensity: 75 to 90% of your Maximum Heart Rate. Hard efforts like HIIT, hill cycling, lap swimming, basketball, or boxing. Talking becomes difficult, and sweat starts within minutes.
Spend more than twelve minutes above 85% in a single session and your body can keep burning calories at a raised rate for up to 24 hours afterward.
Calories are estimated from movement intensity, heart rate, duration, and activity context. Sport sessions improve calorie accuracy by adding structured workout data. Estimates are tailored using your personal profile, including age, sex, height, and weight.
Daily activity is read against your Recovery Score and your Energy Score. A hard day shows up the next morning, and Kira AI accounts for it before recommending your next session.
Kira AI builds a 14-day rolling baseline of your activity patterns. A high intensity day is interpreted against that baseline, not against a population average.
Titanium body, hypoallergenic interior
2.55mm thick, 7.8mm wide, 3 grams
Sizes: US 6–14
Battery: 8 days (Power Mode), 5 days (Performance)
Charging: 30 mins via wireless charger
ECG, PPG, temp sensor, 3x accelerometer
Bluetooth Low Energy, Airplane Mode
iOS & Android compatible
GDPR & HIPAA compliant
"Honestly, I use it because it keeps things simple. I check my activity, calorie burn, and recovery, and Kira tells me what to do next. That's enough for me."
"Good activity tracker if you don't want another app full of graphs. I like seeing my low, medium, and high intensity zones, especially on days when I didn't 'work out' but still moved a lot."
"The calorie burn part is useful because it counts the full day, not just exercise. I can see sleep, rest, walking, and workouts in one place, which makes the numbers feel more real."
Activity tracking is one of 14+ core subscription-free health features built into Circular Ring 2. Your ring connects your activity to everything else your body is doing, from your sleep stages and HRV to your stress, temperature, blood oxygen, ECG readings, breathing patterns, coherence, and cycle data. All 14+ features work as one system, and the insights that Kira AI, the personal AI health coach built in the ring, delivers get sharper because of it. That is what turns activity data into real results, not just another graph to scroll past.
A 40-second ECG from your finger, with irregular rhythm and AFib detection.
Workout insights designed to help you train more effectively.
Shows how much energy you've accumulated based on sleep, stress, recovery, and immune function.
Overnight heart rate variability read against your own baseline, so you can see recovery move.
Circular continuously determines whether you are walking or running and counts for you the number of steps.
Learn when your body is stressed and needs rest or when it is ready to perform.
Circular Ring 2 does not stop at tracking. Kira AI reads your activity intensity zones, calorie burn, sport sessions, sleep, recovery, and HRV together, then writes one clear thing to do today, built on your personal baseline. The action layer is where the results come from.
Circular Ring 2 measures intensity as a percentage of your Maximum Heart Rate. Activity is sorted into three zones: low (40 to 55 percent), medium (55 to 75 percent), and high (75 to 90 percent). The system adapts to your age, gender, and fitness level rather than using a fixed cutoff.
Low intensity is daily routine movement where breathing stays normal, such as walking or stretching. Medium intensity is sustained effort like brisk walking or jogging, where breathing deepens. High intensity is near-peak effort like HIIT or hill cycling, where talking becomes difficult.
Both. Movement is detected by the accelerometer, and effort is read through your heart rate. The two are interpreted together, which is why a hard mental day spent sitting does not get scored as a workout, and a flat walk uphill does not get scored as easy.
The calorie burn tracker uses movement intensity, heart rate, duration, and your personal profile. Active calories are estimated continuously across the day, with additional accuracy added when you log a sport session.
Yes. Circular Ring 2 tracks your total daily energy expenditure, which includes your basal metabolic rate, the calories your body burns at rest just to keep you alive, alongside active calories from movement and exercise. You get the full number, not just the workout slice.
The Activity Circle shows your total daily calories alongside steps, active minutes, cardio points, and VO₂ max. We do not currently show a separate active-calorie and resting-calorie breakdown.
Your profile and personal baseline help us make the estimate relevant to you, alongside ring data such as movement and heart rate. We do not publish every variable or weighting used in the calculation.
Kira AI generates one personalized, actionable recommendation a day, on demand. Daily summaries appear automatically, and pattern detection runs continuously in the background.
Yes. You can log notes about travel, caffeine, alcohol, illness, workouts, late meals, and stress events. Kira folds these into her interpretation, which sharpens the accuracy and relevance of her recommendations.
Yes. Kira AI reads training loads against recovery and energy trends and generates actionable pacing recommendations. This is particularly useful for athletes managing cumulative fatigue across training blocks or peaking for competition.
No. Kira AI does not diagnose conditions, prescribe treatment, or replace medical professionals. It translates biometric signals into lifestyle and behavioral guidance you can act on. For anything clinical, the Circular app generates PDF reports and trend summaries designed to be shared with your doctor.
Yes. We encrypt data between your ring, the app, and our cloud systems. We do not sell your health data or use it for advertising, though we process and share limited data when needed to run, protect, and improve the service.
Circular Ring 2 is not intended to diagnose, treat, cure or prevent any disease, and is not for use in an emergency.
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