Metabolic & Labs
Lab results and metabolic markers. Blood glucose, lipids, and other laboratory values tracked through connected devices.
HbA1c (Glycated Hemoglobin)
Long-term blood sugar control indicator, the gold standard for diabetes management.
Lipid Panel
Cholesterol and triglycerides—HDL, LDL, and cardiovascular risk factors.
Blood Alcohol Content (BAC)
Definition
The concentration of alcohol in the bloodstream, expressed as a percentage or g/dL.
Example: 0.08% BAC = 0.08 grams of alcohol per 100 mL of blood.
Why It Matters
BAC has significant safety and health implications: - Legal limits - Driving limits in most jurisdictions - Impairment assessment - Cognitive and motor effects - Safety decisions - When safe to drive or operate machinery - Health tracking - Alcohol consumption patterns - Medical relevance - Affects medication interactions, health conditions
How It's Measured
- Breathalyzers - Estimate BAC from breath alcohol
- Blood tests - Direct measurement (clinical/legal)
- Estimation apps - Calculate based on drinks, weight, time
- Smart devices - Some wearables estimate BAC
HealthKit data: Typically from estimation apps or connected breathalyzers.
Reference Levels
| BAC | Effects |
|---|---|
| 0.02% | Relaxation, slight mood change |
| 0.05% | Lowered alertness, impaired judgment |
| 0.08% | Legal limit in many jurisdictions; reduced coordination |
| 0.10% | Clear impairment of coordination and judgment |
| 0.15% | Significant impairment, difficulty walking |
| 0.20% | Confusion, nausea, possible blackout |
| 0.30% | Stupor, unconsciousness possible |
| 0.40%+ | Potentially fatal |
Confounders & Limitations
- Individual variation - Body weight, metabolism, tolerance
- Food intake - Eating slows absorption
- Time course - BAC rises and falls over hours
- Device accuracy - Consumer breathalyzers vary in precision
- Estimation errors - Apps provide rough estimates only
Factors Affecting BAC
- Body weight - Lower weight = higher BAC per drink
- Biological sex - Women typically reach higher BAC
- Rate of consumption - Faster drinking = higher peak
- Food - Eating slows absorption
- Carbonation - May speed absorption
- Medications - Interactions with some drugs
Use Cases
- Safety decisions - When safe to drive
- Consumption tracking - Monitoring alcohol intake
- Health awareness - Understanding alcohol effects
- Event planning - Responsible drinking
Important Notes
- Legal BAC limits vary by jurisdiction
- Even below legal limits, impairment occurs
- No amount of alcohol is "safe" for driving
- "Sobering up" only happens with time—coffee/food don't speed it
References
Blood Glucose
Definition
The concentration of glucose (sugar) in the blood, typically measured in mg/dL (US) or mmol/L (international).
Conversion: 1 mmol/L = 18 mg/dL
Why It Matters
Blood glucose is central to metabolic health: - Diabetes diagnosis - Elevated glucose indicates diabetes - Diabetes management - Daily monitoring for treatment - Prediabetes detection - Early intervention opportunity - Metabolic health - Blood sugar regulation reflects overall health - Energy levels - Glucose is the body's primary fuel
How It's Measured
- Fingerstick meters - Traditional home glucose monitors
- Continuous Glucose Monitors (CGM) - Real-time tracking (Dexcom, Libre, etc.)
- Lab tests - Clinical blood draws
- Data sources - Many glucose devices sync to HealthKit
Reference Values (Fasting)
| Category | Fasting Glucose |
|---|---|
| Normal | <100 mg/dL (<5.6 mmol/L) |
| Prediabetes | 100-125 mg/dL (5.6-6.9 mmol/L) |
| Diabetes | ≥126 mg/dL (≥7.0 mmol/L) |
HbA1c (long-term average): - Normal: <5.7% - Prediabetes: 5.7-6.4% - Diabetes: ≥6.5%
Confounders & Limitations
- Timing - Fasting vs post-meal readings differ significantly
- Stress - Acute stress elevates glucose
- Medications - Steroids, some drugs affect glucose
- Illness - Infections can raise glucose
- Sample handling - Improper technique affects accuracy
- Meter accuracy - Consumer devices have ±15% tolerance
Use Cases
- Diabetes monitoring - Daily management
- Prediabetes tracking - Lifestyle intervention assessment
- Dietary impact - How foods affect your glucose
- CGM trends - Time in range, variability
- Medical visits - Sharing data with healthcare team
Time in Range (CGM Users)
Target for most diabetics: - In range (70-180 mg/dL): >70% of time - Below range (<70): <4% of time - Above range (>180): <25% of time
When to Seek Care
- Fasting glucose consistently >100 mg/dL
- Symptoms of high glucose (thirst, frequent urination, fatigue)
- Symptoms of low glucose (shakiness, confusion, sweating)
- Difficulty achieving target ranges
- Any glucose >300 mg/dL or <54 mg/dL
References
Insulin Delivery
Definition
The cumulative amount of insulin delivered, measured in International Units (IU or U). Tracked for people using insulin pumps or smart insulin pens.
Why It Matters
Insulin tracking is essential for diabetes management: - Dosing records - Complete insulin history - Pattern analysis - Understanding insulin needs - Basal vs bolus - Different insulin types serve different purposes - Treatment optimization - Adjusting doses based on patterns - Safety auditing - Preventing errors, tracking usage
How It's Tracked
- Insulin pumps - Automated logging (Omnipod, Tandem, Medtronic, etc.)
- Smart pens - Connected insulin pens (InPen, NovoPen Echo, etc.)
- CGM integration - Automated insulin delivery systems
- Manual logging - User-entered injections
Insulin Types
| Type | Onset | Peak | Duration |
|---|---|---|---|
| Rapid-acting | 15 min | 1-2 hr | 3-4 hr |
| Short-acting | 30 min | 2-3 hr | 5-6 hr |
| Intermediate | 2-4 hr | 4-12 hr | 12-18 hr |
| Long-acting | 1-2 hr | Minimal | 24+ hr |
Key Metrics
Basal Insulin
- Background insulin for fasting glucose control
- Delivered continuously (pump) or as long-acting injection
- Typically 40-50% of total daily insulin
Bolus Insulin
- Covers meals and corrects high glucose
- Rapid/short-acting insulin
- Dosed based on carbs and correction factor
Total Daily Dose (TDD)
- Sum of all insulin delivered in 24 hours
- Used to calculate pump settings
- Varies by individual, typically 0.5-1.0 U/kg/day
Confounders & Limitations
- Incomplete logging - Manual entries may be missed
- Absorption variability - Same dose, different effect
- Site issues - Lipohypertrophy, infusion set problems
- Device sync - Some devices don't connect to HealthKit
Use Cases
- Diabetes management - Daily insulin tracking
- Pattern recognition - Identifying insulin needs
- Healthcare visits - Share complete insulin history
- Pump settings - Optimizing basal rates, ratios
- Closed-loop systems - Automated insulin delivery