All three track sleep and recovery, with no screen. The real difference: what you pay over time.
SSPARRA S1
€99
one-time payment
- No subscription
- 10 days of battery life
- Sleep, HRV, recovery, stress
Polar Loop
€179.90
one-time payment
- No subscription
- 8 days of battery life
- Sleep, HRV, recovery
WHOOP One (entry plan)
€199
per year, subscription
- Subscription required
- 14+ days of battery life
- Sleep, recovery, strain
What you pay, year after year
Cumulative cost of device and subscription, using the WHOOP One plan at €199 per year.
Side by side
| S1 | Polar Loop | WHOOP One | |
|---|---|---|---|
| Price | €99 once | €179.90 once | €199 / year |
| Subscription | No | No | Yes, required |
| Screen | No | No | No |
| Battery life | 10 days | 8 days | 14+ days |
| Sleep and recovery | Yes | Yes | Yes |
| Stress alerts | Yes | Not verified | Yes |
| ECG, blood pressure (beta) | No | No | Yes |
| After-sales service | 100% French | Depends on brand | Depends on brand |
Want to track sleep, recovery and stress without paying every year? The S1 costs €99, once.
Prices and specifications noted in October 2026 on polar.com and whoop.com (WHOOP One entry plan at €199 per year); they may change. WHOOP and Polar, their names and images, belong to their owners, are not affiliated with SSPARRA, and are shown only to identify the compared products. We compare the features each brand advertises, not measurement accuracy. The S1 is a wellness and training tool, not a medical device.