Shifting to an unfamiliar climate can be difficult enough, especially when going between very hot and very cold climates. Researchers from the Centre for Heat and Health Research at the University of Sydney, based on Gadigal land, have found ways that humans adapt physiologically to different temperatures. They explored the behavioral adaptations individuals take to warmer or colder climates. Dr. Harry Brown and Professor Ollie Jay, both renowned experts in this field, provide meaningful insight into the adaptation process and how it’s affecting those moving to help us adapt.
Dr Brown adds that those physiological adaptations to heat exposure are an increased sweat rate and a reduced heart rate. For example, these adaptations enable the body to better tolerate more extreme heat, leading to improved work capacity even in strenuous heat stress conditions. He says these adaptations will evolve pretty soon after, usually within a few weeks’ time.
Professor Jay explains that contrary to this notion, there is a ceiling on the physiological benefits you get from heat exposure. He goes onto describe others—including a decrease in baseline body temperature—adaptations that could be in the cards. These adaptations require much of the time, experience to extreme environments. “The stimulus that’s needed to induce these adaptations is really quite severe,” he states.
Understanding Acclimatisation
Acclimatisation involves two distinct types: physiological and behavioral. Professor Jay explains that physiological adaptations are physiological changes within the body to adjust to environmental conditions. He explains that most of the ways we adapt to cold climates are behavioral rather than physiological.
“There is some evidence our adaptive response to the cold is much more behavioral than physiological,” Professor Jay explains. People have survived extreme cold by acquiring learned practices. This adaptation happens in place of drastic transformations taking place inside their bodies during development.
Dr. Brown further elaborates on behavioral adaptations, which he defines as “the ways in which you respond to an environment.” He stresses the importance of remaining well hydrated. In addition, he stresses the importance of looking for shade and dressing in layers when acclimatizing to hotter weather.
The Role of Routine in Adaptation
For some of these newcomers, developing a simple daily routine can be an enormous help in settling into their new environment and supporting their transition. Sayaka Sayeed, who moved at least four times growing up, explains that having to adjust is “anxiety-provoking but kind of exhilarating. She points out that it typically takes her three to six months to “have all the basics down and figure out [her] new routine.”
Crafting a consistent routine fosters structure in a moment-to-moment world. Sayeed’s point speaks to the need for mental adaptation in addition to physical adaptation when reorienting your community to a new climate.
Dr. Brown urges those just getting their feet wet to start with the low-hanging fruit, as we all navigate this new world. He stresses the need to track your hydration and know exactly how hydrated you are. It’s just as important to know how to keep your body warm or cool by changing what you wear.
The Science Behind Adaptation
The study by Brown and Jay highlights that acclimatisation is not a straightforward process. As Professor Jay points out, “It’s not like you keep on adapting — you plateau.” That is, after the early adaptations have taken place, people might find themselves at a point where ongoing physiological changes become more muted.
He cautions against prevalent myths about acclimatisation. “I think the mistake that most people make is that they assume these physiological adaptations occur more readily than they do,” he says. He stresses that folks tend to assume that these adaptations arise solely from heritable genetic causes or from place of birth. That’s not always the case.
As Professor Jay points out, it is time for a serious re-imagination. He points to a heat acclimation study that had participants training 90 minutes to two hours daily in scorching 45-degree heat including high humidity over seven to ten days straight. These harsh conditions highlight the intensity of exposure required for effective adaptation.
