Gurugram, January 09, 2025.

Samsung has introduced the ‘Good Sleep’ mode, a new featureto promote pleasant sleep throughout the night by adjusting the temperature according to sleep stages. This mode has now been upgraded to allow users to connect their air conditioners with their Galaxy Watch series and have the ‘Good Sleep’ automatically activated when they fall asleep.[1]

The influence of a suitable ambient temperature on sleep is immense. The common experience of waking up in the middle of the night drenched in sweat or shivering in cold, is relatable for most people. It is for this reason that Samsung decided to develop a mode on its air conditioners to help people get better sleep during the night.

The key point in this mode, however, was that the optimal temperature for sleep is not fixed for the entire period that a person sleeps. This is why although many set their air conditioner to the optimal temperature before going to bed, they still wake up. The optimal temperature varies according to the sleep stage a person is at – whether a person is falling asleep, in deep sleep, or waking from sleep. The Samsung team, in 2015, partnered with Kyunghee University to find the optimal temperature for each sleep stage, and develop an adequate algorithm for the air conditioner.

The ‘Good Sleep’ mode fluctuates the indoor temperature over a course of a person’s sleep cycle. Sleep consists of 5 stages – wake, REM (Rapid eye movement), and 3 stages of NREM (Non-rapid eye movement sleep). Each stage of sleep includes variations in brain wave patterns, eye movements, and body temperature. These five stages make up one complete sleep cycle which typically lasts about 90 minutes. Throughout the night, this cycle repeats itself approximately four to six times.

The ‘Good Sleep’ cycle adjusts the indoor temperature according to the stage. First, when a person falls asleep, temperature is quickly lowered within 5 minutes to immediately create a pleasant environment. The temperature is kept low consistently during the next 90 minutes to facilitate deeper sleep. Starting from 90 minutes, the air conditioner increases the temperature to prepare for the deeper stages of sleep – N2 and N3. In these stages, body temperature and blood pressure fall the most, indicating that outer temperature needs to be warmer. Temperature is increased within two degrees above target level to prevent awakening due to cold sensation.

Throughout the eight-hour sleep cycle, alternating periods of lighter REM sleep and deeper NREM sleep occur. The 'Good Sleep' mode continually modifies the temperature throughout the night, adjusting it approximately three times. Approaching the end of sleep, temperature is kept high, but gentle wind is blown to create a refreshing atmosphere.