What’s cooler than being cool?
Longevity is a hot topic; always has been, and always will be. I think it is inevitable that as (mortal) humans it is in our nature to think about the prospects of immortality and consider the implications of living to be over a century old, perhaps even older.
Because of this, we continually search for the “magic pill”, the diet, exercise regimen, or meditation practice that will grant us freedom from the unstoppable decline of our “years left” column.
Sadly, we don’t know what really “works” when it comes to enhancing longevity (in humans, at least). Studying lifespan is technically if not impossibly difficult — since we live so long. It’s easier to study the lifespan of fruit flies, or c. elegans worms, who live such a short life that we can study the impact of a variety of interventions in a compressed period of time.
Putting interventions aside, we know that environment profoundly influences longevity (another factor impossible to isolate). One of those environmental factors, temperature, has been studied due to its associations with lifespan. In this post, I’ll discuss the influences of environmental and body temperature, namely the cold, on health and lifespan.
From a longevity standpoint, a cold environment has been shown to be optimal vs. a warmer environment in terms of median and maximal lifespan in a variety of species. Body temperature is one of the most well known and important factors involved in lifespan; increased body temperature has been shown to negatively associate with longevity (i.e. earlier death) and conversely, lower body temperature is associated with increased longevity and reduced aging.
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Lifespan extension due to cold/reduced body temperature is related variety of mechanisms linked to various “theories of aging.” For example, lower body temperature is associated with a reduced metabolic rate, supporting the “rate of living” theory of aging — that longevity and aging are inversely regulated by metabolic rate. (2). Additionally, immune function and resistance to environmental stressors is increased in organisms born in/living in a cold environment, and so the presence of many disease that occur with age might be lowered.
All of this suggests that people living in cold environments should experience the benefits of a longer life. There isn’t a lot of data on this, and regardless, much of what has been reported is pretty messy. A lot of the tropical (i.e. warmer) countries where average lifespan is lower are poorer/underdeveloped; the additional factor of health care + increased risk of tropical diseases confounds the data.
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An alternative viewpoint to “where should you live (hot or cold) to live longer?” might be “in what environment do you want to be born?” Indeed, the environmental conditions under which one is born profoundly influence internal mechanisms directly and indirectly related to longevity. For instance, being born during the colder season of the year is associated with increased birth weight, gestational age, longevity, and a lower risk of fetal growth restriction and premature birth (4). Temperatures (internal and external) during critical developmental periods might influence the overall rate of aging from birth.
Perhaps babies are metabolically “programmed” in many ways via temperature, involving changes in structure, function, and metabolism of the newborn. Flouris et al cite a prominent example that the response of a newborn to a cold extra-uterine environment, resulting in enhanced brown adipose tissue (BAT) and thus increased activity of uncoupling proteins (UCP): with the net effect of reduced reactive oxygen species (ROS), decreased fat mass, and lower inflammation — all of which separately and distinctly influence pathways involved in longevity. Babies born in colder environments might also gain some of the aforementioned immune/stress resistance benefits arising from reduced temperatures in the neonatal period.
Should I live somewhere cold to benefit my health?
Despite the evidence, personally, I think my longevity is better influenced by warmer environments, but there is also additional evidence that is separate from mechanisms discussed in the previous paragraphs. For instance, warmer environments, where I am happier (subjectively, albeit) can participate (and enjoy) my physical activity, and increase my sun exposure (vitamin D, immune function, etc.) undoubtedly and somehow influence my longevity. Perhaps my inclination arises due to my having been born in the summer months (July) and thus having a genetic expression of temperature sensitive ion channels which predispose me to cold intolerance/extreme cold sensitivity. I do, it turns out, hate the cold. Nevertheless, living in a warm environment subjectively enhances my well-being and surely, down the line, my longevity.
And if cold is all that beneficial, then cryotherapy might just be one way we can mimic the effects of cold environment and get the longevity benefits, if you happen to live somewhere warmer. That, or take a cold shower.
There isn’t really any data to cite (I’m not going to reference longevity.com, sorry) and everything else published on cryo seems to come from studies in athletes for injury reduction/performance and attenuation of muscle damage. Nevertheless, sometimes #anecdotes provide all the evidence one needs.
1. Vriens et al. Peripheral thermosensation in mammals. Nature Reviews Neuroscience 15:573–589 (2014)
2. Conti. Consideration on temperature, longevity and aging. Cell Mol Life Sci. 65(11): 1626–1630 (2008)
3. Flouris et al. Links between thermoregulation and aging in endotherms and ectotherms. Temperature 2(1): 73–85 (2015)