Peaks - Circadian Rhythm Tracker
iOS and Apple Watch app that uses the two-process model of sleep regulation to predict focus, fatigue, and recovery windows. Combines circadian rhythm with sleep pressure using NASA-level science to optimize daily scheduling, with complete offline functionality and local data storage for privacy.
Last updated: 2026-03-18 11:25
Overview
Peaks turns your health data into clear patterns so you can see what helps you sleep, recover, and stay consistent.
Scientific Foundation
Peaks uses the two-process model of sleep regulation, combining your circadian rhythm with sleep pressure to predict focus, fatigue, and recovery windows. It's the same framework used in aviation and shift-work research—the same science behind NASA's astronaut protocols.
Key Features
Energy Tracking
- Energy Peaks: See exactly when focus is highest. Schedule deep work and important tasks during these windows.
- Energy Dips: Know when crashes are coming before they hit. Plan breaks and lighter tasks accordingly.
Sleep Analysis
- Sleep Timing: Track when your body releases melatonin so you know when to dim lights and wind down.
- Sleep Debt: Every missed hour accumulates. See your running total and how it clears over time.
- Recovery Score: HRV and heart rate analysis shows how ready you are for today. Updated every morning.
Apple Watch Integration
Seamless integration with Apple Watch, though Peaks doesn't exclusively require it. Any sleep data that syncs to Apple Health will work.
Privacy
Health data never leaves your iPhone. No sign-ups, no servers, no third parties. Peaks works entirely offline.
Pricing
- Free: Available on the App Store for devices running iOS 18 or watchOS 11 and later
- Peaks Pro: $4.99/month or $29.99/year - unlocks widgets, custom schedules, sleep scores, and calendar integration
Related Items
$450 Billion Context Switching Cost
Estimated annual economic impact of context switching and multitasking on U.S. productivity. Represents the enormous hidden cost of workplace interruptions, task switching, and fragmented attention across the American economy.
1,200 Daily App Switches Statistic
Research finding from Harvard Business Review study showing that average digital workers toggle between applications and websites nearly 1,200 times per day, spending almost 4 hours per week just reorienting after switching apps.
14.8 Hours Weekly Meeting Average
Research showing average professionals spend 14.8 hours per week in meetings, representing 37% of a 40-hour work week. Critical context for understanding why focus time is scarce and why morning time blocks must be protected before meetings consume the day.
Ahead App - Energy Peak Tracker
Productivity app that helps users track their natural energy patterns throughout the day and optimize task scheduling based on circadian rhythms and ultradian cycles. Matches tasks to biological peak performance times for maximum productivity and reduced burnout.