What is the expected rate of algor mortis (body cooling) in a temperate environment (15–20°C) during the first 12 hours after death?

Explanation

## Algor Mortis: Rate of Body Cooling **Key Point:** Algor mortis is the post-mortem cooling of the body towards ambient temperature. The rate of cooling is not constant and depends on environmental and body factors. ### Cooling Rate Timeline | Time Period | Temperature Drop | Rate per Hour | Environmental Assumption | Notes | |-------------|------------------|---------------|--------------------------|-------| | **First 8–12 hours** | 1–1.5°C/hour | 1–1.5°C | Temperate (15–20°C) | Faster initial cooling; larger temperature gradient | | **After 12 hours** | 0.5–1°C/hour | 0.5–1°C | Temperate (15–20°C) | Slower cooling; smaller temperature gradient | | **Plateau phase** | Minimal | ~0°C | When body temp ≈ ambient | Body reaches ambient temperature; no further cooling | **High-Yield:** The classic NEET PG answer for algor mortis in temperate conditions is **1–1.5°C per hour** during the first 12 hours. This is the most frequently tested interval. **Mnemonic:** **ALGOR = 1°C/hour (early phase)** — remember "1 degree per hour" as the baseline for temperate environments in the first 12 hours. ## Factors Affecting Algor Mortis Rate 1. **Environmental temperature** — higher ambient temp → slower cooling; lower ambient temp → faster cooling 2. **Body composition** — obese bodies cool slower (insulation); lean bodies cool faster 3. **Clothing and covering** — insulation slows cooling 4. **Cause of death** — fever before death (e.g., sepsis) → initial faster cooling; hypothermia → slower cooling 5. **Body surface area** — larger surface area → faster heat loss 6. **Humidity** — affects evaporative cooling **Clinical Pearl:** Algor mortis is less reliable than livor mortis for estimating time of death because of the many confounding variables. A body found in a cold environment may cool much faster than the standard 1–1.5°C/hour rate. ## Henssge Nomogram Forensic pathologists use the **Henssge nomogram** (or similar temperature-based calculators) to estimate time of death by accounting for ambient temperature, body weight, and clothing. The simple 1–1.5°C/hour rule is a rough approximation for teaching purposes.