Comparison

Helys vs Peak Intervals

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Helys

Features
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I am Helys, your companion for maintaining optimal vitamin D levels and help you create a healthy and effective habit of safe sun exposure. I am here to empower you and help you harness the power of sunlight for your overall well-being. Main Features: — Vitamin D Tracking I use a scientific formula which considers your skin type, geographical location, time of day, weather conditions and UV index to provide personalized insights on safe sun exposure durations. — Personalized Sunscreen Reminders I will remind you to apply sunscreen based on your skin type and current UV index. — Progress Insights and Reports I want to take care of you and ensure you're meeting your recommended levels of vitamin D. — User-Friendly Interface I have an intuitive interface, which makes it simple and effortless to navigate and track your vitamin D levels. Disclaimer: I do not provide medical advice. Always consult with a healthcare professional for personalized guidance regarding your vitamin D levels and sun exposure habits.

About

Peak Intervals

Features
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Peak Intervals guides two endurance workouts on Apple Watch: the Norwegian 4x4 to train your VO₂ max, and steady Zone 2 sessions to build your aerobic base. Your iPhone follows along live and shows how each session went. Guided workouts need Apple Watch and a Peak Intervals Pro subscription, with a 2-week free trial where available. History, Trends and the analysis of your Apple Health workouts are free. NORWEGIAN 4x4 • Four 4-minute intervals at 90–95% of your max heart rate, with 3-minute recoveries. • Live guidance keeps you in the zone: haptic cues on your wrist, and voice cues with headphones. • Afterwards, see whether you reached the zone quickly, stayed in it during every interval, held your pace or power from the first interval to the last, and how fast your heart rate came down in each recovery. ZONE 2 • Run, ride, row or walk on an incline, indoors or outdoors, with a guided warm-up and cool-down. • An alert tells you when you drift out of the zone, and a talk test at 15 minutes asks how the effort feels. • Afterwards, see how much of the session you spent in the zone, whether your heart rate crept up at the same effort (decoupling), and how your power or pace at Zone 2 heart rate compares with your last session of the same activity. ZONES THAT FIT YOU • Your max heart rate starts from an age estimate and goes up if a recent workout in Apple Health reached a higher heart rate. • Zone 2 uses your Apple Health heart rate zones on iOS 27, or your resting and max heart rate. • Your talk test answers help tune the zone: after three easy sessions the app offers to raise it, and when talking gets hard it offers to lower it. You decide. TRENDS AND HISTORY • Compare your last 3 sessions with the 3 before, with a clear verdict such as Improving or Stable. • See your VO₂ max and resting heart rate from Apple Health next to your training. • Every session in one place, including workouts from Apple Health. • Share a session as a story or post, with your own photo in the background. APPLE WATCH AND iPHONE Workouts start and record on Apple Watch. Your iPhone follows live, also on the Lock Screen and in the Dynamic Island. Apple Health Peak Intervals reads workout and heart rate data from Apple Health (HealthKit) to calculate your metrics and trends. You control what is shared at any time in iOS Settings. Subscriptions Peak Intervals offers an auto-renewing subscription with monthly and yearly plans, including a 2-week free trial where available. After the trial, an active subscription is required to start new workouts. Payment is charged to your Apple ID account at confirmation of purchase. Subscriptions renew automatically unless canceled at least 24 hours before the end of the current period. You can manage or cancel your subscription in App Store account settings. Peak Intervals is not a medical device and does not provide medical advice. High-intensity exercise may not be appropriate for everyone. Consult a physician before beginning a new training program. Privacy Policy: https://peakintervals.app/privacy Terms of Use: https://peakintervals.app/terms

Screenshots

Helys4 screens
Peak Intervals4 screens

Verdict

The call

The clearest difference is in-app purchases: Helys at none against Peak Intervals's 2. Helys also leads on iOS requirement (16.0 vs 26.0). Peak Intervals's advantage is update cadence (every 4 days vs every 3 months). On price, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Peak Intervals sells 2 in-app purchases, starting at $9.99 per month. Helys asks for nothing beyond the download.

UpkeepUpdate frequency

Helys ships an update every 3 months, Peak Intervals every 4 days. The most recent releases landed on October 10, 2026 and October 11, 2026 respectively.

Scorecard3 real differences · 3 level
Helys versus Peak Intervals: the parameters behind the verdict, then further details
ParameterHelysPeak Intervals
PriceFreeFree
Update frequencyEvery 3 monthsEvery 4 days — better
AdsNoNo
In-app purchasesNo — betterYes
DevicesiPhoneiPhone, Apple Watch — better
Requires iOS16.0 — better26.0
Further details — not scored
Size3 MB18 MB
Age rating12+17+
DeveloperAntonio PalombaJustin Polidori

In-app purchases

None

Helys

No in-app purchases

2 purchases

Peak Intervals

Subscriptions2
  • Pro3 Days trial$9.991 Month
  • Pro Yearly14 Days trial$49.991 Year

Questions

Is Helys free?
Helys is free to download, with no in-app purchases.
Is Peak Intervals free?
Peak Intervals is free to download, with in-app purchases available.
Do Helys or Peak Intervals have ads?
Neither Helys nor Peak Intervals shows ads.
Which is updated more often, Helys or Peak Intervals?
Helys ships an update every 3 months, and Peak Intervals every 4 days. Most recently, Helys was updated on October 10, 2026 and Peak Intervals on October 11, 2026.

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