Your Data, Connected
Leo's correlation engine cross-references your symptoms, medications, vitals, weather, and lifestyle to find the patterns that matter. No AI — just statistical analysis of your own data that makes every doctor visit more productive.
Correlation Engine
Discover connections hidden in your health data
Leo's built-in correlation engine cross-references your symptoms, medications, vitals, sleep, weather, and lifestyle data to surface patterns you might never notice on your own. No AI — just statistical analysis of your own data to help you understand what truly affects your health.
Sleep-Symptom Correlations
Understand how rest affects your health
- Sleep duration impact on next-day symptoms
- Sleep quality correlation with energy and mood
- Optimal sleep window recommendations
- Sleep debt accumulation and symptom severity
- Wake time consistency and symptom patterns
Vital Sign Trend Analysis
See how your body metrics relate to how you feel
- Heart rate variability and symptom occurrence
- Blood pressure patterns and lifestyle factors
- Blood glucose trends with meal context
- Resting heart rate and recovery patterns
- Multi-metric correlation insights
Medication Effectiveness Tracking
Measure how well your treatments are working
- Symptom improvement after medication start
- Time-to-relief measurements for each drug
- Side effect onset and duration tracking
- Dose timing optimization suggestions
- Adherence correlation with symptom control
Mood & Energy Patterns
Track emotional and energy fluctuations
- Daily energy rhythm mapping
- Mood correlation with activities and events
- Stress impact on physical symptoms
- Social activity influence on wellbeing
- Seasonal mood pattern detection
Flare-Up Pattern Detection
Understand what leads to your worst days
- Flare-up frequency and duration tracking
- Common factors present before flare-ups
- Weather and barometric pressure correlations
- Sleep quality impact on symptom days
- Medication timing and symptom control analysis
Long-Term Trends
See the big picture of your health journey
- Monthly and yearly health summaries
- Treatment effectiveness over time
- Lifestyle change impact measurements
- Seasonal pattern identification
- Progress toward health goals
Conditional Correlations
Discover how a third variable changes the relationship between two others
- Stratified analysis by high/low conditioning variable
- e.g. Sleep-mood link strengthens when adherence is high
- Automatic scanning of meaningful variable triplets
- Median-split grouping with per-group Pearson correlation
- Only surfaces when correlation difference exceeds 0.2
Threshold Segmentation
See how outcomes change across low, medium, and high ranges
- Tercile binning (low / mid / high) for predictor variables
- Average outcome computed per bin with sample counts
- Cohen's d effect size between low and high groups
- e.g. Mood averages 7.2 with 7+ hrs sleep vs 4.8 with <6 hrs
- Actionable ranges you can target for improvement
Weekday vs Weekend Patterns
Compare how correlations shift between workdays and rest days
- Separate Pearson correlations for Mon–Fri vs Sat–Sun
- Average value comparisons across day types
- Percentage difference highlighting (e.g. 15% higher on weekends)
- Identifies routine-dependent vs routine-independent factors
- Requires at least 2 weeks of data for reliable results
Recency-Weighted Analysis
Detect whether correlations are getting stronger or weaker over time
- Exponential decay weighting (30-day half-life)
- Compares recent-weighted r vs equal-weighted r
- Flags strengthening patterns (e.g. recent r=0.72 vs overall r=0.45)
- Flags weakening patterns that may indicate positive change
- Helps you see if lifestyle changes are working
Self-Prediction Cycles
Find out if today's values predict your state days from now
- Autocorrelation at 1, 2, 3, and 7-day lags
- Detects carry-over effects (good days lead to more good days)
- Detects rebound patterns (high followed by low)
- Best-lag selection with statistical confidence scoring
- e.g. Your mood today predicts your mood 2 days later (r=0.65)
Perfect For
Migraine Sufferers
Discover that your migraines occur 2.5x more often when you sleep less than 6 hours AND have high stress, allowing you to prioritize rest during demanding periods.
Chronic Condition Management
Identify that your symptoms improve 40% when you maintain consistent meal timing and medication schedules, motivating you to build better routines.
Autoimmune Flares
Detect that stress levels and sleep quality two days prior correlate with flare-ups, giving you awareness of your personal triggers.
Everything Included
Private & On-Device Analysis
Your health insights are protected by industry-leading security. Analysis happens on your device when possible, and all cloud processing is encrypted end-to-end.
On-Device Processing
All analysis runs locally on your iPhone using our on-device correlation engine — your data never leaves your phone
You Control Sharing
Choose exactly what to include in reports and who can access your health insights
HIPAA Coming Soon
Enterprise-grade security and compliance for all your health data
Insights Everywhere You Need Them
Access your health intelligence across all your Apple devices
iPhone App
- Complete pattern analysis dashboard
- Trigger correlation engine
- Trigger tracking with weather
- PDF report generation
- Share reports directly to providers
Apple Watch
- Log symptoms and medications quickly
- View upcoming medication reminders
- Heart rate and vital monitoring
- Complications for health metrics
- Sync data automatically to iPhone
Widgets & Notifications
- Daily insight widget
- Pattern alert notifications
- Trigger warning push alerts
- Weekly summary notifications
- Smart suggestion reminders
Continue exploring Leo
Discover Your Health Patterns Today
Join the beta and unlock health insights you never knew existed with Leo