N2nap in a nutshell

Why it matters

Most nap timers solve the wrong problem. They set an alarm — they don't account for the time it takes to fall asleep.

This creates two issues:

1. Shortened naps. A 20-minute timer that starts at button press delivers inconsistent amounts of actual sleep, depending on how long it takes to fall asleep that day.
2. Deep sleep risk. If you compensate by setting a longer timer, you risk entering N3 (deep sleep). Research shows 54.8% of ~30-minute naps end in deep sleep, and waking from N3 causes sleep inertia — grogginess that can impair performance for up to 30 minutes.

N2nap solves both by starting the countdown at sleep onset and using science-guided durations that target N2 sleep — the stage associated with restored alertness and memory consolidation — while ending before deep sleep begins.

Key features

• Sleep onset detection — Apple Watch sensors identify when you fall asleep. The countdown starts there, not at button press.
• Science-guided presets — Default durations based on sleep stage timing research, targeting the N2 window.
• Haptic wake — A gentle tap on the wrist. No audio alarm to disturb others.
• Nap history — Track naps, onset latency, and sleep duration over time.
• Apple Health sync — Nap data integrates with Apple Health (optional, user-controlled).
• No account required — No signup, no login. Data stays on device.

The science behind it

Sleep progresses through stages. During a nap, you pass through N1 (light transition sleep) into N2, where the brain produces short bursts called sleep spindles. Research links spindles to restored alertness, memory consolidation, and learning capacity.

Most people reach N2 within 3–7 minutes of falling asleep and stay there for 10–25 minutes before risking entry into N3 (deep sleep). The ideal nap captures N2 while ending before N3 begins.

The NASA study everyone gets wrong

The landmark NASA study (Rosekind et al., 1995) gave pilots a 40-minute rest window and measured ~26 minutes of actual sleep — finding a 54% improvement in alertness and 34% improvement in performance. But those results were measured from sleep onset, not from the moment pilots closed their eyes. Average onset latency was 5.6 minutes. N2nap's approach mirrors this methodology.

Pricing

N2nap is completely free.

Full nap timer with onset detection, haptic wake, nap history, and Apple Health sync. No subscription. No ads. No account required.

Origin story

The common advice is "take a 20-minute nap," but that assumes you fall asleep instantly. In reality, sleep onset varies from day to day — sometimes 3 minutes, sometimes 15. A 20-minute timer is only as good as that assumption. N2nap was built to close the gap between the timer and actual sleep.

Story angles

1. "The only nap timer that counts from sleep onset"

   The mechanism story. Immediately understandable, easily demonstrated.

2. "The NASA nap study: what it actually measured"

   Most people misquote the study. The real protocol measured from sleep onset within a longer rest window — exactly what N2nap does.

3. "No subscription, no ads, no account"

   A completely free indie app in a market full of subscriptions. Privacy-first: all data stays on device.

4. "Apple Health companion"

   Apple is expanding health and wellness features. N2nap complements the ecosystem with nap-specific optimization.

Reviewer's guide

Setup (2 minutes)

1. Install N2nap on Apple Watch via the App Store or TestFlight.
2. Open N2nap on the watch. No account setup — the app is immediately ready.
3. Select a nap duration (default: 20 minutes).

Taking a nap

1. Tap Start and place your wrist down naturally (as if resting).
2. The watch displays "Monitoring..." as it waits for sleep onset signals.
3. When onset is detected, you'll feel a subtle confirmation tap and the countdown begins.
4. At the end of the countdown, a gentle haptic pattern wakes you.
5. A summary screen shows: actual sleep duration, onset latency, and total time.

What to look for

• The onset gap. Compare your onset latency (shown in the nap summary) to the timer you set. The difference is the sleep you'd lose with a regular timer.
• Consistency. Take 2–3 naps on different days. Notice how onset latency varies but actual sleep duration stays consistent.
• Haptic wake. Gentle enough to not startle, firm enough to wake reliably.

Known limitations

• Sleep onset detection uses heart rate and motion heuristics, not clinical EEG. Accuracy is within approximately 3 minutes of clinical polysomnography.
• Detection works best when the watch has a snug fit and the wearer is in a quiet resting position.
• Very short naps (under 8 minutes of target sleep) may not allow reliable onset detection.

FAQ

Contact

For review copies, interview requests, or additional assets:

[email protected]