Effects of Daylong Exposure to Indoor Overheating on Thermal and Cardiovascular Strain in Older Adults: A Randomized Crossover Trial.
| Autor: | Meade, Robert D.1,2, Akerman, Ashley P.1, Notley, Sean R.1, Kirby, Nathalie V.1, Sigal, Ronald J.1,3,4,5,6, Kenny, Glen P.1,6 gkenny@uottawa.ca |
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| Předmět: |
*Climatology
*Smoking *Diseases *Temperature Mortality Self-evaluation Statistical power analysis Effect sizes (Statistics) Body temperature regulation Body mass index Data analysis Research funding Statistical sampling Human research subjects Questionnaires Sample size (Statistics) Home environment Randomized controlled trials Population geography Restraint of patients Descriptive statistics Heat Crossover trials Hydration Heart beat Cardiovascular system physiology Informed consent (Medical law) Statistics Health outcome assessment Comparative studies Data analysis software Body fluids Confidence intervals Dehydration Time Old age |
| Zdroj: | Environmental Health Perspectives. Feb2024, Vol. 132 Issue 2, p027003-1-029002-3. 14p. |
| Abstrakt: | BACKGROUND: Health agencies recommend that homes of heat-vulnerable occupants (e.g., older adults) be maintained below 24–28°C to prevent heat-related mortality and morbidity. However, there is limited experimental evidence to support these recommendations. OBJECTIVE: To aid in the development of evidence-based guidance on safe indoor temperatures for temperate continental climates, we evaluated surrogate physiological outcomes linked with heat-related mortality and morbidity in older adults during simulated indoor overheating METHODS: Sixteen older adults [six women; median age: 72 y, interquartile range (IQR): 70-73 y; body mass index: 24.6 (IQR: 22.1-27.0 kg/m²] from the Ottawa, Ontario, Canada, region (warm summer continental climate) completed four randomized, 8-h exposures to conditions experienced indoors during hot weather in continental climates (e.g., Ontario, Canada; 64 participant exposures). Ambient conditions simulated an air-conditioned environment (22°C; control), proposed indoor temperature upper limits (26°C), and temperatures experienced in homes without air-conditioning (31°C and 36°C). Core temperature (rectal) was monitored as the primary outcome; based on previous recommendations, between-condition differences >0.3C were considered clinically meaningful. RESULTS: Compared with 22°C, core temperature was elevated to a meaningful extent in 31°C [+0.7C; 95% confidence interval (CI): 0.5, 0.8] and 36°C (+0.9C; 95% CI: 0.8, 1.1), but not 26°C (+0.2C, 95% CI: 0.0, 0.3). Increasing ambient temperatures were also associated with elevated heart rate and reduced arterial blood pressure and heart rate variability at rest, as well as progressive impairments in cardiac and blood pressure responses to standing from supine. DISCUSSION: Core temperature and cardiovascular strain were not appreciably altered following 8-h exposure to 26°C but increased progressively in conditions above this threshold. These data support proposals for the establishment of a 26°C indoor temperature upper limit for protecting vulnerable occupants residing in temperate continental climates from indoor overheating. [ABSTRACT FROM AUTHOR] |
| Databáze: | GreenFILE |
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