HormonesMelatonin

Heat stress disrupts sleep in older adults by prolonging sleep onset, fragmenting slow-wave and REM sleep, and suppressing melatonin secretion.

This narrative review synthesizes evidence that elevated nighttime temperatures disrupt sleep in older adults through multiple mechanisms, including prolonged sleep onset, fragmentation of slow-wave and REM sleep, and suppression of melatonin secretion. Age-related declines in thermoregulatory capacity, such as reduced sweating and impaired vasodilation, exacerbate these effects. The review notes that sex-related differences, particularly menopause-associated vasomotor instability in women and testosterone-related autonomic changes in men, further modulate individual vulnerability.

Last updated: Jul 31, 2026•0 RCTs•📖 Read as article →

Evidence Score

Evidence Score32/100
Human RCT☆☆☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Mechanisms of Heat-Induced Sleep Disruption in Aging: A Narrative Review.

observational

Ezgin N, Krčum J, Šutulović N, Pavlović M, Djurić E, Mladenović D, Vesković M, Cetin AE, Rašić-Marković A, Stanojlović O, Hrnčić D · Clocks & sleep (2026)

Participants: N/A
Duration: N/A
Intervention: Heat stress (elevated nighttime temperatures)
Outcome: Sleep disruption (sleep onset latency, slow-wave and REM sleep fragmentation, melatonin suppression)
Effect Size: N/A
Population: Older adults (aging populations with age-related thermoregulatory decline)

Result: This narrative review synthesizes evidence that elevated nighttime temperatures disrupt sleep in older adults through multiple mechanisms, including prolonged sleep onset, fragmentation of slow-wave and REM sleep, and suppression of melatonin secretion. Age-related declines in thermoregulatory capacity, such as reduced sweating and impaired vasodilation, exacerbate these effects. The review notes that sex-related differences, particularly menopause-associated vasomotor instability in women and testosterone-related autonomic changes in men, further modulate individual vulnerability.

PubMed: 42496250DOI: 10.3390/clockssleep8030043

Mechanism Graph

Elevated nighttime temperatures increase thermal load on the body
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Age-related declines in thermoregulatory capacity (reduced sweating, impaired vasodilation, diminished hypothalamic responsiveness) impair heat dissipation
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Thermal stress activates sympathetic overactivation and suppresses melatonin secretion
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Result: Prolonged sleep onset, fragmentation of slow-wave and REM sleep

Limitations

  • ⚠Many proposed mechanistic pathways are primarily derived from animal models, not human studies
  • ⚠Controlled human studies specifically targeting heat-exposed older adults remain scarce
  • ⚠The review is narrative and does not provide quantitative meta-analytic effect sizes

Frequently Asked Questions

How does heat stress affect sleep in older adults?▼

Heat stress prolongs sleep onset, fragments slow-wave and REM sleep, and suppresses melatonin secretion, primarily due to age-related declines in thermoregulatory capacity.

Are there sex differences in heat-induced sleep disruption?▼

Yes, menopause-associated vasomotor instability in women and testosterone-related autonomic changes in men modulate individual vulnerability to heat-induced sleep disruption.

What environmental factors amplify heat-related sleep problems in older adults?▼

Socioeconomic disparities, urban heat island exposure, and differential access to cooling infrastructure function as critical environmental modifiers that amplify biological vulnerability.

What interventions are suggested to mitigate heat-induced sleep disruption?▼

Interventions include environmental cooling, circadian-aligned behaviors, and targeted public health strategies to reduce compounded risks of heat exposure.

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References

  1. 1.Ezgin N, Krčum J, Šutulović N, Pavlović M, Djurić E, Mladenović D, Vesković M, Cetin AE, Rašić-Marković A, Stanojlović O, Hrnčić D. "Mechanisms of Heat-Induced Sleep Disruption in Aging: A Narrative Review.." Clocks & sleep, 2026. PMID: 42496250 DOI: 10.3390/clockssleep8030043
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.