High rebound mattress toppers facilitate core body temperature drop and enhance deep sleep in the initial phase of nocturnal sleep.
Level 2 - randomized trial
Randomized single-blind crossover trial
PubMed 29949584 · doi:10.1371/journal.pone.0197521
What was done
Researchers evaluated the physiological and sleep effects of high rebound (HR) versus low rebound (LR; memory foam) mattress toppers. The study used a randomized, single-blind, crossover design in 30 healthy adult males (10 young and 20 older participants). Nocturnal core body temperature (CBT) and EEG deep sleep/delta power were measured, alongside a separate daytime assessment of muscle activity during rollover movements.
What was found
Sleeping on HR compared to LR resulted in a significantly greater drop in minimum CBT during early nocturnal sleep in both young (36.05 °C with HR vs. 36.35 °C with LR) and older subjects (36.47 °C with HR vs. 36.55 °C with LR). This was associated with an increase in early-night (11:00–01:00) deep sleep delta power (+27.8% in young, +24.7% in older men). In separate daytime testing, HR reduced rollover-associated muscle activation by -53.0% to -66.1% depending on the muscle measured.
Why it matters
Mattress mechanical properties can influence thermoregulation and sleep architecture, suggesting that high-rebound sleep surfaces may facilitate core heat dissipation and initial slow-wave sleep better than conforming memory foam.
Limits
The study had a small sample size (n = 30 total) and included only healthy male participants, limiting generalizability to females and clinical populations. Blinding was single-blind and likely challenging given tactile surface differences, and long-term sleep outcomes were not assessed.