Paper Summary
Title: Passive Heat Exposure Alters Perception and Executive Function
Source: Frontiers in Physiology
Authors: Rachel A. Malcolm et al.
Published Date: 2018-05-25
Podcast Transcript
Hello, and welcome to paper-to-podcast. Today we're diving into a topic sure to raise your temperature, or at least make you think twice before going to that hot yoga class right before an important brain-storming session.
We'll be discussing a research paper published in Frontiers in Physiology titled, "Passive Heat Exposure Alters Perception and Executive Function" authored by Rachel A. Malcolm and colleagues. The date of publication? 2018-05-25. But, don't sweat it if you didn't catch it back then, we've got you covered.
Get your beach towel ready. This study put 41 rather sweaty chaps from the United Kingdom through their paces, not on a football pitch, but in a hot room with the temperature turned up to a sizzling 39.6 plus or minus 0.4 degrees Celsius. The purpose of this sauna-like scenario? To see what happens to your noggin when the heat is on!
Turns out, after an hour of lounging in this heated room, these guys became slower at tasks requiring quick thinking and decision making. Imagine running a mental marathon in a desert. Their speed dropped by around 38 milliseconds on a simple visual search test and by the same amount on a more complex test affectionately named after a chap called Stroop. But, here's where it gets interesting! While they were slower, they were also more accurate, their accuracy leapt from 96.8% to 98.1% on the complex visual search test. It's as if their brains said, "Easy there, hot shot, let's take our time with this one."
But it wasn't all sunny skies and improved accuracy. Their heart rates were higher (well, duh, it was hot), and they reported feeling more confused, depressed, and fatigued. So, the moral of the story? If you have a task that requires quick thinking, you might want to avoid doing it in a sauna, but if it's all about accuracy, crank up the heat!
The design of this research was commendable. The researchers used a randomized crossover design and multiple cognitive function tests, ensuring each participant experienced each condition, reducing individual differences. They carefully controlled the conditions and used best practices in statistical analysis, making sure to keep their participants hydrated and avoiding strenuous exercise prior to the trials.
However, this hot topic does have a few cold spots. The findings only apply to the cognitive domains tested, and other areas might react differently to heat exposure. The study might have benefited from an additional time point to measure cognitive function as core temperature increased further. And while they used a single site for skin temperature measurement, this doesn't provide a whole body measure. Lastly, the order of the cognitive function tests may have caused mental fatigue, potentially exacerbated by the increasingly uncomfortable conditions.
But before we cool down, let's talk about the potential applications. These findings could be significant for fields where cognitive function under heat exposure is crucial, such as firefighting, military operations, and sports medicine. It could inform the development of cooling systems in protective clothing or specific training programs. It could also shape public health guidelines and architectural design in regions with high temperatures.
So, next time you're feeling the heat, remember, you might be a bit slower, but you'll likely be more accurate in your work. Now, if you'll excuse me, I think I'll go turn down the thermostat.
You can find this paper and more on the paper2podcast.com website.
Supporting Analysis
Get ready to have your mind blown! A study involving 41 sweaty guys found that lounging around in the heat (39.6±0.4°C) for an hour made them slower at tasks that required quick thinking and decision making. They were around 38 milliseconds slower on a simple visual search test and a whopping 38 milliseconds slower on a complex level of a test named after a guy called Stroop. However, here’s the twist! While they were slower, they were also more accurate, especially on the complex visual search test where their accuracy jumped from 96.8% to 98.1%. It seems that their brains were saying, "Okay, it's hot, let's not rush this". The study also found that their heart rates were higher in the heat (duh!) and they felt more confused, depressed, and fatigued. So, the takeaway? If you have something that requires quick thinking, maybe avoid doing it in a sauna. But if accuracy is your game, then bring on the heat!
In this research, 41 healthy active males were subjected to varying temperature conditions to study the effects of passive heat exposure on cognitive function. The participants, who were all from the UK, took part in a control trial in a thermoneutral environment and a hot trial in an environmental chamber. In both trials, the participants were asked to complete a battery of cognitive function tests, both before and after one hour of passive rest in their assigned conditions. They were also asked to provide subjective feelings of heat exposure, arousal, and their general feelings. Physiological measures like core temperature, skin temperature, and heart rate were also recorded. The cognitive function tests involved tasks like Visual Search, Stroop, Corsi Blocks, and Rapid Visual Information Processing (RVIP) tests. The participants' responses were then analyzed to draw conclusions about the effects of heat exposure on their cognitive functions.
The researchers in this study adhered to several compelling and commendable research practices. They utilized a randomized crossover design, which is a strong, robust experimental approach that helps to minimize bias and confounding variables. This is especially beneficial as it ensures each participant experiences each condition, reducing the effects of individual differences. Furthermore, they carefully controlled the experimental conditions, ensuring the temperature conditions were well-maintained and consistent. The use of multiple cognitive function tests also helped provide a comprehensive understanding of the effects of heat exposure on different cognitive domains. Moreover, the researchers followed best practices in statistical analysis, using appropriate tests for their data and clearly reporting their results. They also paid attention to participant well-being, ensuring hydration and avoiding strenuous exercise prior to the trials. Lastly, the decision to conduct their study during winter months to prevent heat acclimatization effects was strategic and thoughtful.
This research may have some limitations. Firstly, the findings can only be applied to the specific cognitive domains tested. Additional cognitive areas not tested might react differently to heat exposure. Secondly, the study might have benefited from an extra time point for cognitive function, allowing core temperature to increase further. This could have provided a broader understanding of how both skin and core temperature changes affect cognitive function over a longer period. However, the focus was on short-term effects and the reliability of the data could have been affected by mental fatigue. Thirdly, the use of only one site for skin temperature measurement doesn't offer a whole body measure, but it did allow for a quick and accurate measurement. Finally, using a standardized order for the cognitive function tests may have caused mental fatigue, potentially exacerbated by greater discomfort in the later tests.
This research could have significant implications for a number of fields where cognitive function under heat exposure is crucial. It could be particularly helpful in enhancing safety measures and performance in professions such as firefighting and military operations, where individuals are often exposed to high heat conditions. Moreover, sports medicine could utilize these findings to improve athletes' performance and safety during hot weather events. It could also inform the development of strategies or technologies to mitigate the cognitive effects of heat exposure, such as cooling systems in protective clothing or specific training programs. Furthermore, it could be applicable in addressing cognitive performance issues in regions with high temperatures, potentially shaping public health guidelines and informing architectural design for schools and offices. The findings might also be beneficial in understanding cognitive responses in certain health conditions associated with increased body temperature.