Tuesday, November 1, 2016

How Does Heat Stress Affect the Thinking Ability of Old Men?

Cognitive function and short-term exposure to residential air temperature: A repeated measures study based on spatiotemporal estimates of temperature (Abstract, Lingzhen Dai, Itai Kloog, Brent A. Coull, David Sparrow, Avron Spiro III, Pantel S. Vokonas, Joel D. Schwartz, Environmental Research, Jul. 5, 2016)

Today we review research into the cognitive abilities of a sample of older men (average age 74) in the northeast USA to exposure to indoor temperatures of up to 25.7 C for short periods of time. This is important for at least two reasons: over the next 20 years, climate change will lead to a doubling of the number of days above 30C and, in addition, the number of people over 70 is also expected to double over the next 20 years. Earlier studies indicate that exposure to outdoor temperatures above 32C (and below -10C) led to the greatest drop in cognitive abilities. Heat stress may lead to poor decision making that adds to the health risk that these people face during heat waves. Results indicate that higher temperatures affect hippocampal neural activities that are crucial for brain functions like learning and memory. Both hot and cold temperatures are associated with a loss of cognitive abilities and this may be greater for persons over the age of 70. Further research along these lines is needed to examine the impact on older women. heat-stress-and-thinking  

Key Quotes:

“temperature-induced declines in cognition may lead to poor decision-making ability and executive function (Muller etal.,2012; Racinais etal.,2008). Hence the elderly may not be aware of the need of cooling, hydration,or escaping the heat and put themselves at an elevated risk of danger during heat waves.”

Elderly people are very likely to spend most of their time at their residence. Therefore, it is crucial to understand how residential temperature plays a role in their health”

“reported that exposure to hot temperatures of >32 °C and cold temperatures of <10 °C resulted in the greatest decrement in cognitive performance. Temperature in the current study ranged from -5.8 to 25.7 °C”

“First, characteristics of the study population, such as age and occupation, differed. Second, the way in which the subjects were exposed and how long they were exposed mattered. Last but not least, cognitive tasks of different types and durations could be affected by temperature differentially.”

“that warmer outdoor temperature was linked with greater BOLD activation in frontal and parietal regions of cerebral cortex among subjects with multiple sclerosis. Furthermore, it is established that temperature affects hippocampal neural activities that are crucial for brain functions like learning and memory”

“people are less comfortable in both hot and cold temperatures, and this may flow through to cognitive function via multiple pathways.”

 “Our results suggest a U-shaped relationship between cognitive function and residential temperature: either low or high temperature is associated with an increased risk of impairment in cognitive function. The association among individuals aged >70 years may be stronger.”

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