What Is the Ideal Sleep Temperature?

Bryan Johnson’s 17 August article adds a temperature protocol to his public sleep guidance. It recommends a bedroom range of 60–67°F (15–19°C), with 60–67°F described as favorable for deep sleep and 68–72°F for REM sleep. Johnson says he uses an Eight Sleep mattress that changes temperature during the night and warms before waking. He reports that 71°F for deep sleep and 73°F for REM works best for him, based on tracking REM and deep-sleep measures. The post also recommends breathable bedding, airflow, and a warm bath or shower 1–2 hours before bed. It cites general claims about core-temperature drops, heart rate, and time to fall asleep, but it does not provide a study table, baseline, number of nights, adherence, device, or comparator. The 8-month statement of 100% sleep performance is presented as a personal result. The article includes an affiliate disclosure for Eight Sleep and says individual results vary. This is a protocol recommendation based on an instrumented n=1, not a randomized sleep trial. The useful update is operational: Johnson now specifies different temperature targets for sleep stages and says he adjusts the mattress in real time. The causal claim remains untested because temperature, routine, sleep environment, and device settings are not separated.

The most important thing: Take steps to cool your body before sleep and stop it from overheating at night.