Sleep brand 'NELL (Neru)' has conducted the 'Tropical Nights × Turning During Sleep × Mattress Survey' targeting 1,000 men and women aged 20 to 50 across Japan.

As July arrives and the intense heat continues, this survey reveals that approximately 60% of people feel dissatisfied with their summer sleep, with a large number experiencing 'sweating on the back and waist' and 'body fatigue' upon waking.

However, only 18.1% are aware of the fact that 'turning during sleep' is essential for 'body temperature regulation (heat dissipation)'—a potential root cause of poor summer sleep.

We report on the overlooked factor of 'turning during sleep' and the importance of supportive mattresses, alongside the survey results.

Key Survey Findings

Summer sleep dissatisfaction is severe: 58.4% report dissatisfaction with their sleep every summer, and 72.4% feel negative effects (such as fatigue and sweating) upon waking.

Lack of awareness about 'turning = temperature regulation': 61.8% were unaware that the purpose of turning is 'temperature regulation (heat dissipation).' Only 18.1% answered correctly.

Those who know are more aware of 'insufficient turning': 56.5% of those aware of the role of turning recognize they 'cannot turn properly during sleep,' compared to only 14.7% among those unaware.

Awareness and latent demand for bedding: Only 13.7% have changed their mattress or futon for summer heat relief. However, 38.8% who have never reviewed their mattress say they 'want to in the future,' indicating strong latent demand.

Detailed Survey Results

【1】Current state of summer sleep: Nearly 70% experience 'back sweating' and 'fatigue' upon waking

68.1% have experienced 'inability to sleep or light sleep during tropical nights,' and 58.4% are dissatisfied with their summer sleep annually. Additionally, 72.4% feel negative effects upon waking, with 67.9% reporting specific symptoms such as 'sweating on the back and waist' and 'body fatigue.'

【2】Hidden cause of tropical nights: Over 60% unaware of 'temperature regulation through turning'

'Insufficient turning' may underlie summer sleep dissatisfaction. 61.8% answered they 'did not know' that 'turning = temperature regulation (heat dissipation).' Only 18.1% correctly identified the purpose.

Interestingly, 56.5% of those aware of turning's role recognize they 'cannot turn properly at night,' while only 14.7% of those unaware have this self-awareness. This suggests many suffer from heat buildup due to insufficient turning without realizing it.

Self-awareness of 'insufficient turning' by knowledge of its role:

Those aware of the role: 56.5%

Those unaware: 14.7%

【3】Current state of summer heat countermeasures: Mattress review remains low at just over 10%, but latent demand reaches nearly 40%

The most common heat countermeasure is 'air conditioning adjustment (38.8%),' while only 13.7% have 'changed their mattress or futon.' However, 29.1% have considered 'ease of turning' when choosing a mattress, and 38.8% who have never reviewed their mattress say they 'want to in the future,' indicating growing interest in bedding.

Why is 'turning during sleep' important for summer sleep?

Humans enter deep sleep (non-REM sleep) by lowering core body temperature. During tropical nights, heat and humidity easily get trapped between the body and bedding, making it difficult for body temperature to drop. 'Turning during sleep' is an essential action to release (dissipate) this trapped heat.

As 51.2% of respondents believe 'the speed of post-turning temperature drop varies by material,' choosing a mattress that allows easy turning and has high breathability is the essential path to quality summer sleep beyond just relying on air conditioning.

Why the 'NELL Mattress,' designed for turning, is chosen for better summer sleep

The 'NELL Mattress' is a pocket coil mattress designed to support comfortable 'turning during sleep' and enhance restful sleep.

Over 1°C difference in urethane comparison! Exceptional breathability for efficient heat dissipation

Its unique multi-layer structure, alternating thin urethane and non-woven fabric, achieves higher breathability than conventional urethane mattresses.

In testing, after 2 minutes of use, the surface temperature of a standard urethane mattress was 26.2°C, while the NELL Mattress was 25.0°C—a difference of over 1°C. The independent structure of the pocket coils creates airflow, preventing heat buildup even on tropical nights, reducing 'back sweating' and 'body fatigue' upon waking.

Survey Overview

Purpose: To understand actual summer sleep conditions and awareness of 'turning during sleep' and 'mattresses' during tropical nights

Target: 1,000 men and women aged 20–50 across Japan

Period: July 6–8, 2026

Method: Online survey

About NELL, the sleep brand enhancing 'sleep recovery'

Launched in October 2020, NELL is a D2C sleep brand. It views sleep as 'preparation' and aims to provide 'high-quality preparation = sleep' so that individuals can perform at their best in daily life beyond sleep hours, through continuous product research and development.

• Official website: https://nell.life/

About the sleep media 'WENELL (Weineru)'

'WENELL (Weineru)' was launched with the idea of comprehensively delivering useful information to help solve sleep-related concerns. We hope users will take various actions based on WENELL's content to discover bedding and routines that suit their individual needs. • WENELL: https://nell.life/wenell/

Company Overview: Morght Inc.

Founded: May 23, 2018 Representative: CEO Kota Doi Business: Planning and sales of D2C sleep brand 'NELL' products Headquarters: 3rd MINAMI AOYAMA 6F, 3-1-34 Minami-Aoyama, Minato-ku, Tokyo Capital: 33.12 million JPY

• Company website: https://morght.com/

• Official Instagram: https://www.instagram.com/nell_mattress/

• Official X (formerly Twitter): https://twitter.com/NELL_mattress

• Sleep media 'WENELL (Weineru)': https://nell.life/wenell/

FACT BOX

  • Source: PR TIMES
  • Category: Survey