Evaluating the Efficacy of Lower Leg Immersion With and Without Neck Cooling for Limiting Heat Strain in Elderly Adults During Extreme Heat Events
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 18
- 试验地点
- 2
- 主要终点
- Core temperature
研究概览
简要总结
The incidence and severity of hot weather and extreme heat events (heat waves) is increasing. As such, there is an urgent need to develop heat-alleviation strategies that can provide targeted protection for older adults who are at an elevated risk for heat-induced illnesses or death due to impaired body temperature and cardiovascular regulation. While air-conditioning provides the most effective protection from extreme heat, it is inaccessible for many individuals and cannot be used during power outages (e.g., heat-related rolling blackouts). Immersion of the lower limbs in cold water and/or the application of cold towels to the neck have been recommended as simple and sustainable alternatives to air-conditioning. However, empirical data to support the efficacy of these interventions for mitigating physiological strain and discomfort in older adults is lacking. To address this knowledge gap, this randomized crossover trial will evaluate the effect of lower limb immersion with and without application of cold towels to the neck on body core temperature, cardiovascular strain and autonomic function, dehydration, and thermal comfort in adults aged 65-85 years exposed to simulated heat wave conditions (38°C, 35% relative humidity) for 6 hours.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Double (Participant, Outcomes Assessor)
盲法说明
Participants will be informed of the study interventions before providing informed consent but will be masked to the specific trial until exposure (i.e., participants will not know the cooling intervention before the trial or during baseline measurements). Data will be blinded prior to analysis.
入排标准
- 年龄范围
- 65 Years 至 85 Years（Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Male or female adults.
- •Aged 65-85 years.
- •Non-smoking.
- •English or French speaking.
- •Ability to provide informed consent.
排除标准
- •Physical restriction (e.g., due to disease: intermittent claudication, renal impairment, active proliferative retinopathy, unstable cardiac or pulmonary disease, disabling stroke, severe arthritis, etc.).
- •Use of or changes in medication judged by the patient or investigators to make participation in this study inadvisable (e.g., medications increasing risk of heat-related illness; beta blockers, anticholinergics, etc.)
- •Cardiac abnormalities identified via 12-lead ECG during an incremental exercise test to volitional fatigue (performed for all participants).
- •Peak aerobic capacity (VO2peak), as measured during an incremental exercise test to volitional fatigue, exceeding the 50th percentile of age- and sex-specific normative values published by the American College of Sports Medicine (ACSM).
结局指标
主要结局
Core temperature
时间窗: End of heat exposure (hour 6)
Rectal temperature measured as an index of core temperature (15 minute average)
次要结局
- Rate pressure product(End of heat exposure (hour 6))
- Heart rate(End of heat exposure (hour 6))
- Diastolic blood pressure(End of heat exposure (hour 6))
- Fluid consumption(End of heat exposure (hour 6))
- Change in plasma volume(End of heat exposure (hour 6))
- Orthostatic intolerance symptoms assessment(End of heat exposure (hour 6))
- Systolic blood pressure(End of heat exposure (hour 6))
- Cardiac response to standing from supine (30:15 ratio)(End of heat exposure (hour 6))
- Thermal comfort(End of heat exposure (hour 6))
- Heart rate variability: RMSSD(End of heat exposure (hour 6))
- Systolic response to standing from supine(End of heat exposure (hour 6))
- Integrated baroreflex sensitivity (sit-to-stand maneuvers)(End of heat exposure (hour 6))
- Fluid loss(End of heat exposure (hour 6))
- Heart rate variability: SDNN(End of heat exposure (hour 6))
研究者
Glen P. Kenny
Full Professor, University Research Chair
University of Ottawa