# Fitbit Air vs Amazfit Helio Strap: the scores compared

Facts about other products checked: 2026-10-09.

Canonical page: https://pulse.portlabs.in/compare/fitbit-air-vs-amazfit-helio-strap/

Both are screenless bands that work without a subscription. The Helio Strap reports Amazfit's BioCharge energy score and a weekly PAI total; the Air reports Google's Daily Readiness and Cardio Load. The two sets of scores are built from different inputs and are not interchangeable.

## What each band is

The Helio Strap launched in June 2025 at $99.99, the same price tier as the Fitbit Air ($99 at its May 2026 launch). Reviewers say the strap works without a subscription; Amazfit sells an optional Zepp Aura Premium plan ($11.99 a month or $69.99 a year, as reported). Google Health Premium is the Air's optional extra.

One caution on the Helio side: BioCharge was announced as coming soon at launch, and Amazfit has moved Readiness and BioCharge around between devices since. I could not confirm from Amazfit's own pages how it stands on the Helio Strap today, so check the Zepp app's release notes before buying for that score.

## The scores side by side

Checked 2026-10-09. Amazfit's pages were read through search excerpts; confirm in the Zepp app.

| Question | Fitbit Air (Google Health) | Amazfit Helio Strap (Zepp) |
| --- | --- | --- |
| Morning readiness | Daily Readiness, 1-100: HRV, resting heart rate, recent sleep | Readiness (on some devices): sleep resting heart rate, sleep HRV, breathing quality, skin temperature, once each morning |
| All-day energy | No equivalent | BioCharge: a percentage from HRV, stress, activity and sleep |
| Training load | Cardio Load, with a weekly Target Load | PAI: weekly heart-rate points, target 100 a week; also a Training Load |
| Sleep | Sleep Score 0-100, six published components | Sleep score; Amazfit gives no breakdown of weights |
| Stress | Resilience (Optimal, Balanced, Low) | Stress, no method on the technology page |

## PAI and Cardio Load are close cousins

These are the most comparable pair. PAI (Personal Activity Intelligence) turns your heart rate during the week into points, using your age, sex, resting and maximum heart rate, and sets 100 points a week as the target. Cardio Load turns heart rate during activity into a load number, using age, resting heart rate and sex, and weights harder effort more. Both are heart-rate based and both reward a mix of moderate and hard effort. Neither tells you whether you are recovered; that is the readiness score's job.

Amazfit says 100 PAI a week is linked to a longer life, which is Amazfit's claim; treat it as a target, not a promise.

## Readiness: same name, different inputs

Amazfit's Readiness leans on sleep-time measurements (resting heart rate, HRV, breathing, skin temperature). Google's current Readiness page lists HRV, resting heart rate and recent sleep. Both need a few nights of wear before the number means much, and both are lowered by the same things: a short night, alcohol, illness, a late meal. If yours is stuck low, [the checklist for Fitbit Readiness](https://pulse.portlabs.in/blog/fitbit-readiness-always-low/) covers the usual causes.

## What the reviews say about depth

TechRadar's comparison of the Helio Strap with the Polar Loop and WHOOP 5.0 says the strap's readiness stats lack the depth of WHOOP's system, and calls the Zepp subscription neat but not necessary for most owners. That is one reviewer's view, not Amazfit's claim, and it is worth reading next to the Android Authority review before you buy.

Google's scores have no all-day gauge. Amazfit's BioCharge is one, which is the clearest functional difference between the two bands. Whether it counts for or against the Air depends on whether you want that gauge. If you are only after a morning number and a weekly activity total, the two are close.

## Checks before you buy either

- Look at which scores your phone and region actually show. Reviewers report Zepp's BioCharge rollout has been uneven across devices, and SpO2 on the Air is reported as unavailable in some regions.
- Decide whether you want a coach. Google Health Premium and Zepp Aura Premium both sell one, and both are optional.
- Remember that history stays in each ecosystem. Switching later means new baselines in the other app.

## Where Pulse fits

Pulse does not read Amazfit bands. For a Fitbit Air owner, it computes a 0-100% [Recovery](https://pulse.portlabs.in/metrics/recovery/) and a 0-21 [Strain](https://pulse.portlabs.in/metrics/strain/) from the Air's data, and [Energy Bank](https://pulse.portlabs.in/metrics/energy-bank/) as its all-day gauge. It is free and self-hosted, needs Docker and a Google Cloud project, and is tested on the Fitbit Air only.

## Questions

### Does the Amazfit Helio Strap need a subscription?

Reviewers report that it does not for day-to-day use. Amazfit sells an optional Zepp Aura Premium plan. Check Amazfit's current terms.

### Is Amazfit PAI the same as Fitbit Cardio Load?

No, but they are similar. Both turn heart rate during activity into a number. PAI is a rolling weekly total with a target of 100; Cardio Load is a daily figure that Google also compares against a weekly target.

## Sources

- [Android Authority: Amazfit Balance 2 and Helio Strap launch](https://www.androidauthority.com/amazfit-balance-2-helio-strap-launch-3570260)
- [Android Authority: Amazfit Helio Strap review](https://www.androidauthority.com/amazfit-helio-strap-review-3570632)
- [TechRadar: Amazfit Helio Strap vs Polar Loop vs WHOOP 5.0](https://techradar.com/health-fitness/fitness-trackers/amazfit-helio-strap-vs-polar-loop-vs-whoop-5-0-which-should-you-buy)
- Zepp Health: technology and algorithm pages (read via search excerpts)
- [Google Health Help: Daily Readiness](https://support.google.com/googlehealth/answer/14236710?hl=en)
- [Google Health Help: Cardio Load and Target Load](https://support.google.com/googlehealth/answer/15402655?hl=en)