Apple's new Watch Ultra 4 is here, and the headline feature is a training readiness score — something Garmin users have enjoyed for years. Apple may be late to the party, but based on testing by Outside Online, its version may be the most approachable one yet.
The readiness score sits on a simple 1-10 scale with plain-English guidance: 0-1 means "Recover," 2-4 means "Pace Yourself," 5-7 says you're "Ready," and 8-10 tells you to "Go For It." That's a friendlier read than Garmin's 1-100 scale, which many casual athletes find overwhelming. The score is built from sleep, activity, vitals and heart rate data, with HRV (a key recovery marker) sampled every five minutes around the clock and heart rate checked every five seconds — a big step up from the Ultra 3. In testing, the reviewer's scores landed at 5-6 daily and matched how they actually felt, though scores only arrive after your morning workout rather than first thing.
Underpinning it all are new sensors that Apple claims are the most accurate wrist-based heart rate trackers on the market, backed by a study spanning participants of different ages, sexes, body types and skin tones. The upgraded hardware also powers a redesigned iPhone health app arriving later this year, with an Insights tab, personalised coaching via Apple Intelligence, a "Health Age" feature and a Longevity tab tracking everything from sleep to metabolic health.
For travellers, the battery story matters most. The Ultra 4 lasts up to 50 hours in normal use — eight more than the Ultra 3 — and 18 hours of full-power workout tracking. Fast charging is the quiet win: 15 minutes on the charger adds 18 hours of runtime, enough to cover a night of sleep tracking. Extended Workout mode stretches to 25 hours with full GPS and heart rate, or 45 hours of GPS-only tracking — handy for long hiking days without a power outlet.
The catch? Dedicated endurance watches still crush it. Garmin's Enduro 3 runs 120 hours of GPS (320 with solar), and the new Coros Pace 4 Pro offers 60 hours for $350 less. If you're racing 100-milers, Garmin remains the default. If you're a hiker, runner or regular gym-goer who also wants calls, maps and notifications on your wrist, the Ultra 4 finally hits a comfortable balance. The cheaper Apple Watch Series 12 gets the same readiness features but maxes out at 24 hours of battery, and only these two models have the new sensor hardware.
Bottom line: serious-but-normal athletes get a genuinely useful recovery tool with battery life that no longer gets in the way. Pure metrics obsessives should still look at the Coros Pace 4 Pro or Suunto Run 2 and pocket the difference.
