Features/Activity & Energy

Want better Health? Get engaged with your Energy levels

Improve your energy levels and immune system like never before thanks to sophisticated tracking, easy-to-read insights and pertinent recommendations.

EnergyRing 78%
Today 84energy score
Ready to train
Kira

Energy is high today. Good day for a run, if you want one.

HRV +12 msSlept 7h 33m
One day, as the ring saw it

Energy is spent across a day, not in a workout.

Movement intensity · 06:00 to 23:00

11,480steps

Active minutes

68

Calories

2,410

Cardio points

42

VO₂ max

48

06:0010:0014:0018:0023:00
Everyday movement Run, detected automatically · 8.4 km Recovery windows

Nothing was started by hand. The run at 18:10 was recognised on its own, priced against the morning's energy score, and folded into the day's load.

Why it matters

A powerful tool for smarter decision

Your energy levels aren't just about how you feel; it's about what's happening inside your body and mind as it adapts to daily stressors before you feel it. Circular gives you quantified metrics, so you make informed decisions each day.

82Move
64Zones
93Steps

Three daily targets, set from your own history rather than a round number someone picked.

Three parts to the score

Join the fitness revolution

84out of 100

Improve your energy levels

The Energy score is the ultimate score that tells you how much energy you have accumulated for the day. It is made up of many night and day markers so that you can evaluate your vitality and know every morning if you can surpass yourself or if you may avoid intensive activities and focus on rest.

Sleephigh
HRVhigh
Resting HRmid
Activity loadmid
Temperaturelow

Data you can count on

Circular calculates your energy levels based on many physiological contributors: Physical Activity, Sleep, Heart Rate Variability (HRV), Resting Heart Rate (RHR), temperature variation, Blood Oxygen Saturation and Breathing Rate. These metrics are calibrated to your baseline, which means that your score is personal to you.

Zone 1 · 6 min
Zone 2 · 11 min
Zone 3 · 18 min
Zone 4 · 6 min
Zone 5 · 0 min

Data driven training

Getting the most out of training doesn't always require working harder: it requires working smarter. Quantify your physical activities and optimize your effort with heart rate training range.

How to read it

What each training zone is actually for.

Zones are set from your own maximum and resting heart rate, so the same run lands differently for two people — as it should.

Zone 1

Very light. Warm-up, cool-down, and the walking that fills most days.

Zone 2

Conversational. Builds the aerobic base most people are short of.

Zone 3

Steady effort. Where most runs and rides actually sit.

Zone 4

Threshold. Hard, sustainable for a while, expensive to recover from.

Zone 5

Maximum. Short intervals only — and the ring will price it tomorrow.

The science

Fueled by Science

Heart Rate Variability (HRV), Resting Heart Rate (RHR), Blood Oxygen Saturation and Breathing Rate get a lot of attention nowadays. It has uses for athletes to optimize their training, for professionals and individuals wanting to check on overall wellness and is studied globally for its correlation to our autonomic nervous system and stress. The HRV analysis is a powerful and reliable metric that is made easy to track with Circular.

  • MeasuredHeart rate, HRV, SpO₂, breathing rate, skin temperature, motion.
  • DerivedEnergy score, activity load, training zones, VO₂ max estimate, cardio points.
  • PersonalEvery threshold comes from your own two-week calibration, then keeps updating.
  • WhereThe finger, where arteries sit closer to the surface than at the wrist.
  • WhenContinuously, including in the shower and the pool.
Designed for your everyday use

The effect of your sleep on your energy and the effect of your activities on your sleep

By wearing Circular 24/7, you'll get feedback on every moment of the day. Kira will reveal how your body is responding to things like physical activity, rest, stress, travel, and work, so you can find the right balance and make smarter decisions when it comes to recovery or training.

Last night sets today's ceiling

Deep sleep, HRV and resting heart rate decide how much load today can absorb — which is why the energy score arrives with the morning, before you have done anything.

Today sets tonight's target

A hard session moves your wind-down earlier and raises the sleep you need. The ring says so in the evening rather than in hindsight.

The routine

Biohack your way to energy gain

Make the most of your day by improving your energy

1

Track your energy levels each day and trends over time.

2

Understand your body and learn about the parameters that positively or negatively impact your energy levels and how it correlates with your sleep & activities.

3

Build better habits for better performance.

Questions

Before you train with it.

More in the help centre.

Walking, running, cycling and swimming are recognised without pressing anything. Anything else can be logged by hand, and the ring still counts the heart-rate cost.

Yes, though a barbell against titanium is hard on any ring. Many people move it to the other hand or take it off for heavy sets — the day's data closes the gap from heart rate either side.

It is recovery expressed as something usable: what you have available today, drawn from last night's sleep, your HRV, resting heart rate, temperature and the load you have been carrying.

Yes. Swims are detected, and the ring is made to be worn in water — showers, baths and swimming included.

It is an estimate from heart-rate response to known effort, useful as a trend rather than a lab number. Watch the direction over months, not the digit.

No. Activity, zones, VO₂ max, the energy score and Kira's recommendations are included with the ring, permanently.

Next

Your sleep also has a great impact on your energy

Learn how
Man on stone steps wearing the Circular Ring 2 in gold titanium
Get to know yourself. Full circle.

Start with one day.

Wear it tomorrow and read what the day actually cost you.

Buy now Get a sizing kit
Man on stone steps wearing the Circular Ring 2 in gold titanium
Get to know yourself. Full circle.

Start with one day.

Wear it tomorrow and read what the day actually cost you.