Tossing and turning at night, waking up frequently in the early hours? Perhaps it’s not that you aren’t tired enough, but that the temperature of your sleep environment is off.
As a mattress research enthusiast, I have always been keenly interested in the latest developments in sleep science. Today, based on the latest scientific research data from 2025, I will provide an in-depth analysis of how temperature affects sleep quality and share some practical advice to help you achieve higher-quality rest by optimizing your sleep microclimate.
01 The Scientific Basis of Temperature and Sleep
The human body undergoes complex physiological changes before and after falling asleep, in which thermoregulation plays a key role. As we prepare for sleep, our core body temperature naturally drops, which is an important signal triggering sleep. This physiological process prepares the body for the onset of deep sleep, which is essential for cognitive function, memory consolidation, and overall well-being.
Sleep is not a uniform process but consists of multiple stages that cycle. Based on electroencephalogram (EEG) characteristics, sleep can be divided into non-rapid eye movement sleep(NREM) and rapid eye movement sleep(REM).
NREM sleep can be further divided into three stages, N1 to N3, with the N3 stage being what we commonly call deep sleep, which is most crucial for physical and mental restoration. Throughout the night, REM and NREM sleep alternate approximately every 90 minutes.
The impact of temperature on sleep is mainly reflected in two aspects: affecting the time it takes to fall asleep and affecting sleep quality. An appropriate temperature can help the body fall asleep quickly and maintain deep sleep; whereas an inappropriate temperature can lead to frequent nighttime awakenings, disrupting sleep continuity.
02 Unveiling the Optimal Sleep Temperature Range
Multiple studies have attempted to identify the temperature range most conducive to sleep. The National Sleep Foundation (NSF) in the US suggests that keeping the bedroom temperature between 15.5°C and 19.4°C (60°F and 67°F)is ideal. Research involving over 34,000 participants found that sleep quality tends to decline as bedroom temperatures exceed 16°C (approximately 60°F).
A new study published in March 2025, focusing on adults aged 65 and older, found that participants’ sleep efficiency was highest and restlessness lowest when the bedroom temperature was between 20 and 25 degrees Celsius (68°F and 77°F). Among these, 20 degrees Celsius (68°F) was identified as the most ideal temperature point for this group.
It’s not just the ambient room temperature that matters; the bedding microclimate is equally critical. Research indicates that people fall asleep most easily when the temperature within the bedding is between 32°C and 34°C (approximately 90°F to 93°F). If the bedding temperature is too low, the body has to expend energy to warm it up, which not only consumes body heat but can also stimulate brain cortex activity, prolonging the time to fall asleep.
A 2020 study testing different settings of a temperature-controlled mattress found that when the bedding microclimate temperature was maintained at 31.45-32.50°C (approximately 89°F to 90.5°F), subject satisfaction rates could exceed 85%, and sleep efficiency was highest.
The China Sleep Research Association’s report on sleep-related home environment standards also points out that in winter, with the use of bedding for warmth, the comfortable sleep temperature for the human body is between 27-32°C (approximately 81°F to 90°F).
03 Latest Scientific Research on How Temperature Affects Sleep
A groundbreaking study published in 2025 offers a new perspective on understanding the relationship between temperature and sleep. A research team from Fudan University’s School of Public Health, in collaboration with several institutions, conducted a nationwide longitudinal study based on over 23 million days of sleep monitoring data collected from wearable devices.
The results, published in a prestigious journal, showed a significant negative correlation between ambient temperature and sleep duration. Specifically, for every 10°C increase in the daily mean temperature, the risk of insufficient sleep increased by 20.1%, and the total sleep duration decreased by 9.67 minutes. More crucially, the study also found that different sleep stages were affected by temperature to varying degrees.
Deep sleep was the most affected by temperature increases, with its duration proportion decreasing by 2.82%, followed by dream (REM) sleep duration decreasing by 2.20%, and light sleep duration decreasing by 2.02%. This means that high temperatures not only reduce total sleep time but, more detrimentally, impair the most restorative deep sleep stage.
Another study published in May 2025 explored the improvement in sleep quality through dynamic temperature regulation. The research found that using a temperature protocol involving “initial warming followed by cooling” could significantly enhance sleep quality.
Specifically, for both women and men, cooling after an initial warming phase significantly improved sleep quality by 13.2% and 7.2%, respectively. Through large-scale data analysis, the researchers identified ideal temperature protocols tailored to different genders.
04 Differential Effects of High and Low Temperatures on Sleep
The detrimental effects of a high-temperature environment on sleep are particularly evident. One study using climate models estimated that rising nighttime temperatures could lead to humans losing an average of 44 hours of sleep per year. By 2099, annual sleep loss could further increase to 50-58 hours.
>When the nighttime temperature exceeds 30°C (86°F), the average sleep duration decreases by over 14 minutes. Compared to a baseline temperature of 5°C-10°C (41°F-50°F), the probability of people sleeping less than 7 hours increases by 3.5 percentage points when the minimum nighttime temperature is above 25°C (77°F).
The mechanism by which heat affects sleep lies in the fact that for the body to dissipate excess heat, the surrounding environment typically needs to be cooler than the body temperature. The initiation of human sleep is often synchronized with the drop in core body temperature. When the ambient temperature is too high, this process is hindered, leading to delayed sleep onset and lighter sleep.
Low-temperature environments can also disrupt sleep. Research has found that at 13°C (55.4°F) compared to a more normal 25°C (77°F), people experience significantly reduced NREM sleep, especially REM sleep, and increased wake time.
When the total thermal resistance of bedding is small, compared to high-temperature environments, low-temperature environments disrupt sleep more strongly, manifesting as increased duration of wakefulness and light sleep (N1), and shortened durations of NREM and REM sleep, thereby reducing sleep quality.
05 Population Differences in Temperature Sensitivity
Studies show that sensitivity to temperature varies significantly among different populations. Older adults are more sensitive to temperature changes. Compared to younger and middle-aged adults, the sleep of those over 65 is significantly more sensitive to increases in nighttime ambient temperature.
This increased sensitivity appears rapidly after age 60 and further increases after age 70. The 2025 study specifically targeting the elderly also identified the 20-25°C (68-77°F) range as most favorable for their sleep.
Gender is also a factor. Under the same conditions, women are more susceptible to the effects of temperature fluctuations. This may be because women’s core body temperature begins to drop earlier in the evening, meaning they enter sleep while exposed to relatively higher temperatures. Additionally, women generally have a thicker layer of subcutaneous fat, which might affect nighttime heat dissipation.
Socioeconomic factors also play a role. Research indicates that residents of poorer regions may experience greater sleep loss due to nighttime temperatures compared to those in high-income countries.
By the end of the century, residents of low-income countries could face sleep loss approximately three times greater, and the elderly could experience about double the sleep loss.
06 Practical Strategies for Optimizing Sleep Temperature
Based on the latest scientific research, here are several practical recommendations for optimizing your sleep temperature:
1. Create a Dynamic Sleep Temperature Environment
Research suggests that a nighttime sleep environment temperature that follows a U-shaped curve(first decreasing, then increasing) is more conducive to improving sleep quality. A gradually decreasing ambient temperature after falling asleep can delay the timing of the body’s temperature minimum, potentially increasing the duration of deep sleep.
In the later stages of sleep, a gradually increasing temperature can help the body prepare for waking up, improving alertness the next day. Smart climate control devices or bed systems can simulate this ideal temperature curve, creating a sleep environment that better aligns with physiological needs.
2. Personalized Temperature Regulation
Given the varying temperature sensitivity among different populations, personalized temperature regulation is crucial. The 2025 research proposed optimized temperature protocols for different genders, indicating that starting with low heating followed by a cooler setting can enhance sleep quality.
For the elderly, women, and those sensitive to temperature, paying special attention to the regulation of the sleep environment and choosing suitable bedding and temperature control strategies is particularly important.
3. Bedding Selection and Sleep Environment Optimization
Choosing the right mattress and bedding is essential for maintaining an ideal sleep microclimate. In winter, consider using a temperature-regulated mattress or a heated mattress pad to maintain the bed microclimate temperature within the ideal range of 31-32°C (88-90°F).
Studies show that in cold seasons, warm bedding can help older adults fall asleep faster and improve sleep efficiency by 5%. In summer, opt for mattresses and bedding with good breathability to help dissipate heat and moisture.
Besides temperature, humidity control should not be overlooked. A relative humidity of 50%-60%inside the bedding is most comfortable. Maintaining good ventilation not only aids temperature regulation but also prevents high carbon dioxide levels from affecting sleep quality.
Conclusion
Rising global temperatures are already having a substantial impact on our sleep health. One study predicts that by 2099, due to increased nighttime temperatures, people could lose 50 to 58 hours of sleep per year. Facing this challenge, we need to more actively optimize our sleep environment temperature.
As a mattress research enthusiast, I believe that future sleep technology will become more intelligent and personalized. Smart mattresses capable of automatically adjusting temperature based on individual physiological characteristics and sleep stages will become effective tools for improving sleep quality. Investing in a mattress that can regulate the sleep microclimate is no longer a luxury but an important investment in health.
Sleep is a cornerstone of health, and the right temperature is an invisible guardian of high-quality sleep. Tonight, why not pay attention to your sleep environment temperature? A small adjustment could lead to a completely different sleep experience.