Sleep is not rest.
It is active recovery. Understanding what happens during sleep changes how you think about what you sleep on.
What the body does during sleep
During deep sleep, the body repairs muscle tissue, consolidates memory, regulates hormones, and strengthens the immune system. Growth hormone is released almost exclusively during deep sleep. Testosterone and cortisol are recalibrated. The glymphatic system clears metabolic waste from the brain.
REM sleep plays a critical role in emotional regulation, creativity, and long-term memory formation. The average adult cycles through four to six sleep stages per night, each lasting approximately 90 minutes. Disruptions to any stage reduce the quality of recovery.
Temperature and sleep quality
Core body temperature needs to drop by approximately one degree Celsius to initiate sleep. Materials that trap heat disrupt this natural cycle.
Synthetic foams absorb and retain body heat. They restrict airflow and create a microclimate that can be several degrees warmer than the room. This leads to restlessness, night sweats, and fragmented sleep.
Wool actively regulates temperature. Its crimped fibres create air pockets that insulate in cold conditions and ventilate in warm ones. Wool can absorb up to 30% of its weight in moisture without feeling damp.
30%
Wool can absorb up to 30% of its weight in moisture without feeling damp, drawing perspiration away from the skin and releasing it into the air.
Chemicals in the sleep environment
Synthetic mattresses can release volatile organic compounds (VOCs) through off-gassing. These compounds are released slowly from foam and adhesive materials over the lifetime of the product.
Research into the effects of long-term, low-level VOC exposure continues to develop. What is established is that these compounds are endocrine disruptors. substances that can interfere with the body's hormonal systems.
Aeris mattresses contain no synthetic foam, no polyurethane, and no synthetic chemicals. The sleep environment stays clean, breathable, and free from off-gassing.
Sleep, hormones, and recovery
HGH
Human growth hormone is released almost exclusively during deep sleep. Essential for tissue repair, muscle recovery, and cellular regeneration. Disruptions to deep sleep directly reduce HGH output.
10 to 15%
Sleep restriction of even one week has been shown to reduce testosterone levels by 10 to 15% in healthy young men. Testosterone rises during sleep and peaks in the early morning.
REM
For women, disrupted sleep affects progesterone and oestrogen regulation, with implications for menstrual health, fertility, and menopausal symptom management. Quality sleep supports the full hormonal cycle.
The mattress is the single largest surface the body is in contact with for the longest period of time. What it is made from matters.
Sleep better on natural materials.
Every Aeris mattress is 100% natural. No synthetic foam. No chemicals. Handmade in England.