平熱

• Reading: へいねつ
• Romaji: heinetsu
• Kanji breakdown: 平 (hei) — normal, ordinary, level; 熱 (netsu) — heat, fever, temperature
• Pronunciation: /heː.ne.tsɯ/

Meaning

Normal body temperature. The baseline body temperature of a healthy individual when not ill.

A noun describing a person's typical healthy resting temperature, used as the reference point for determining whether someone has a fever. Average Japanese adult 平熱 is around 36.0–37.0°C, though individual baselines vary. Clinically relevant when assessing whether a temperature reading constitutes a 発熱 (fever). Also used figuratively to mean a calm, unexcited state.

Examples

1. 朝起きて体温を測ったところ、37.5度あり平熱より1度高かった。 When I took my temperature after waking up, it was 37.5°C—one degree higher than my normal body temperature.
2. 体調不良が続いていたが、今日はようやく平熱に戻った。 I hadn't been feeling well for a while, but today my temperature finally returned to normal.
3. 人によって平熱には差があり、36度台前半の人もいれば37度近い人もいる。 Normal body temperature varies from person to person—some people run in the low 36s while others are close to 37.

Usage Guide

Context: health, daily life, illness, medicine, fever management

Tone: neutral

Origin & History

Sino-Japanese compound: 平 (hei) means normal, ordinary, or level, and 熱 (netsu) means heat, fever, or temperature. Together they describe the baseline or 'level' temperature of the body. The concept became standardised with the adoption of clinical thermometry in the Meiji era.

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal