New Paper: Age at Menarche and Its Potential Role in Early Detection of Hyperandrogenic Polycystic Ovary Syndrome

I will be upfront in that I had absolutely nothing to do with this design and data collection of this study. Lead author, the amazing and brilliant Courtney Manthey, led this study and she wanted to better understand if there is a connection between early age at menarche and Polycystic Ovary Syndrome (PCOS). She was also interested in if there are potential evolutionary reasons for the existence of PCOS, but that didn’t make it into the paper. She asked me to collaborate in the interpretation of the results in an energetics framework. I don’t say this to wash my hands of this work – quite the opposite! More that I only had the tiniest of roles in this work and credit goes to Courtney.

She found that early age at menarche is associated with developing PCOS, but we still have a lot of unanswered questions. In terms of evolution, an early age at menarche would mean growth stops sooner than it would have otherwise. This would lead to smaller body sizes and a decreased energetic demand to maintain that small body – a potential benefit in our ancestral environments. This might help explain the high heritability of PCOS, but again, lots of work needs to be done to confidently say this.

New Paper: Exploring the Use of Thermography for Monitoring Recovery in Division-I Collegiate Female Soccer Players

Recently, I have been collaborating with Notre Dame Athletics on some fun work. This is a little bit a of a new context for me, formally working with athletics, and it has been a lot of fun. It is really wonderful to be able to collaborate with people with different backgrounds but similar research interests.

This collaboration came about because I have thermal imaging experience because of my work with brown adipose tissue. ND Athletics wants to run a pilot study to see if we could use thermal (infrared) images to track athlete recovery and potentially even identify body regions that are extra hot or cold potentially indicating an emerging injury.

We worked with women’s soccer players and limited our analysis to the lower body, taking thermal images before and after practices and matches.

Sample thermal images of the lower body in the anterior (upper left), left lateral (upper right), posterior (lower left), and right lateral (lower right) views.

We found that increased player load was associated with a decrease in surface temperatures of the lower body. This could be due to muscle damage and recovery – blood flow would be restricted during this process leading to cooler surface temperatures. Conversely, the body could be using peripheral cooling to maintain core body temperature within a normal range and improve recovery. However, there is a great deal more work that needs to be done to better understand how we can use thermography to track recovery.

New Paper: Energetic Value of Women’s Work: Assessing Maternal Energetic Costs From Acorn Foraging

This research was the direct result of a conversation at a conference. Conversations and ideas fly at conferences, but I am not sure I have ever had one go from just talking to collecting data within a few short months.

Our collaborator, Dr. Alexandra Greenwald, is an archaeologist interested in what women were doing and the technologies they used to not only care for children, but also maintain their subsistence activities. For this study, looked at the metabolic cost of gathering acorns. then we compared that cost to the cost of gathering acorns while carrying a “child” (it was a sandbag) in a sling and then in a cradle that can be worn on the back or set down. We measured metabolic cost as well as caloric return on acorns gathered.

Left: woman carrying a sandbag baby in a cradle while foraging for acorns. She is wearing a mobile metabolic unit.

Right: woman gathering acorns while carrying a sandbag baby in a sling. She is also wearing a mobile metabolic unit.

Results were not significantly different for this study, but we were also only able to measure among six participants. However, the trends do indicate that the cradle improved foraging efficiency, demonstrating the importance of improved technology enabling women to maintain their activities while also caring for children. This is a great basis and model for examining the impact of early technologies on foraging efficiency as well as the importance and impressive nature of women’s work.

Figure demonstrating the energy expenditure, foraging returns, and return efficiency of different carrying technologies.

New Paper: Estimated energetic demands of thermoregulation during ancient canoe passages from Tahiti to Hawaii and New Zealand, a simulation analysis

This work was one of those fun collaborations that kind of came out of nowhere. Lead author, Alvaro, contacted me out of the blue one day asking if there were a way I could help him estimate the metabolic costs of long overseas journeys like the ones that ancient peoples did when traveling to and inhabiting Hawaii and New Zealand. For this model, we focused particularly on just resting metabolism as that was a key first step. We hope to add activity costs in the future when we are able to get some better empirical evidence of the metabolic cost of this particular kind of seafaring.

Alvaro brought the calculating, modeling, and coding skills. Myself and Dr. Alexandra Niclou managed the metabolic work. Atholl and Scott provided the geographic and archaeological contexts for this work. We found, that following Bergmann’s and Allen’s Rules, that individuals with larger body sizes would have faired better during the harsh sea conditions of these long journeys. The larger body sizes would have meant less heat loss in wet and windy conditions, and it seems females faired better than males in these models.

It was a beast of math and estimates on estimates, of course, making our certainty with these numbers lower than we might like. However, this is the first work of its kind and provides a basis for future work to refine the model and improve its accuracy. So, consider this the first step in trying to determine the metabolic/physical demands of seafaring and prehistoric overseas colonization.

New Paper: Indication of mixed glucose and fatty acid use by inferred brown adipose tissue activity in Samoans

I am very behind on updating the website with new publications, so these will be quick summaries.

This research was conducted by Dr. Alexandra Niclou and her team in Samoa, and looked at substrate metabolism in brown adipose tissue (BAT). The Samoan individuals in this study exhibited brown adipose tissue activity, and their BAT metabolized a mix of glucose and fatty acids.

Violin graph demonstrating that the Samoans in this study used a mix of fatty acids and glucose to fuel brown adipose tissue activity.

This is different from what we have seen in other populations for whom BAT substrate metabolism has been documented. For example, BAT among the Sakha of Siberia seems to preferentially use glucose. While reindeer herders in Finland exhibit BAT that uses a majority fatty acids.

This work demonstrates that there is a great deal of individual in interpopulational variation in BAT activity and substrate utilization. We still do not know why variation in substrate utilization exists. It could be driven by dietary differences, mitochondria level differences, and potentially even the intriguing possibility that BAT has anaerobic and aerobic metabolic components.

Human Bodies in Extreme Environments

This is the big review article I wrote for Annual Review of Anthropology covering the ways humans have adapted and acclimatized to extreme environments. I talk about the class big three (hot, cold, high altitude) and then discuss emerging extremes such as climate change and socioeconomic disparities.

This is a great article for undergraduate classes because of its scope, citations, and accessibility.

Scientific American Biological Sex Commentary

The indomitable Dr. Charles Roseman and I have a commentary out in Scientific American. In it we discuss the ever-controversial topic of sex and gender. We present a question first framework, as the questions should drive the ways in which we operationalize sex. We contend that a strict sex binary is useful in some circumstances (evolutionary questions about sexual reproduction or utilizing historical demographic data, for example), but in others it is inadequate (e.g., associations between the sexes, hormones, and athletic performance).

We also discuss why non-human comparisons are not particularly helpful in the current debates, and suggest that “Scientists like us would do well to embrace intellectual humility and listen carefully before deciding that any one definition of sex is useful for understanding the living world.”

Thank you to Kate Wong for working with us on this commentary

Scientific American: Woman the Hunter

Growing up, my family made regular trips to Borders Books (yes, that still existed in my childhood). The first thing I did upon entering the story was run to the magazine section and check out the latest issue of Scientific American. I loved the accessibility of the articles and clear, engaging graphics. Scientific American instilled my love of science early on; however, never did my 10-year-old-self imagine writing for Scientific American much less having an article be the cover story.

Well, today the article I wrote with Dr. Sarah Lacy hits the stands, AND it is the cover story! A massive thank you to Kate Wong for approaching us to write the story and working with us to produce the final version. We also want to thanks Samantha Mash for the gorgeous artwork both on the cover and the inside spread. Thank you also to the whole production crew for pulling together the figures and layout.

This has been wonderful and overwhelming. Thank you to all the friends and family who have supported us through this process and continue to support us through the social media frenzy.

Important to note, the SciAm article is based on our two American Anthropologist articles you can find here: https://anthrosource.onlinelibrary.wiley.com/…/aman.13915

And here: https://anthrosource.onlinelibrary.wiley.com/…/aman.13914

They are behind a paywall, so PLEASE email us for copies!

https://www.scientificamerican.com/article/the-theory-that-men-evolved-to-hunt-and-women-evolved-to-gather-is-wrong1/

Human Cold Adaptation: An unfinished agenda v2.0

Nine years ago, I was in my final year of graduate school and gave my first ever talk at the Human Biology Association. My talk was about the interactions between physical activity and thermoregulation I assessed for my dissertation research. After I presented, an older gentleman with a kind smile, but who I did not know, came up to me and said how impressed he was with my presentation and work. I put out my hand to shake his and glanced briefly at his name tag…It was Ted Steegmann.

I was stunned and awestruck. I had read and gained so much inspiration from Ted’s work on human adaptability. To me, at the time, he was one of those people who stood large in my life, but I never imagined I would meet him much less receive a compliment from him. His 2007 paper on the unfinished human cold climate agenda, based on his Pearl Memorial Lecture for the Human Biology Association, was formative for me.

Fast forward to 2022, when I have established a research program in Finland examining cold climate adaptations and their impact on human health, and was invited to present at the Human Biology Association plenary session on Humans at the Extremes. This plenary was organized by the brilliant Drs. Alexandra Niclou and Mallika Sarma, and they asked me to present on human adaptation to cold.

I knew immediately that I would model my talk and subsequent paper after Ted’s original unfinished agenda. This paper, is as much a tribute to Ted as it is good review of cold adaptations and road map for future research. Having this paper come out is a bit of a full circle moment for me, one leaving me with a deep sense of gratitude.

COVID-19 and Exercise: Part I

Back in May 2020 (which, let’s be honest, feels like a decade or more ago), I hadn’t been to a gym in over two months and I lost so much of my hard earned muscle mass. COVID-19 has had a devastating effect on almost every facet of everyone’s lives. There are the obvious health and socioeconomic hardships experienced due to the pandemic. There were other aspects the pandemic harmed as well such as social connections and routine disruption. One such disruption was to exercise routines. Due to gym and wellness center closures and altered work-home situations, many people had to drastically shift how and where they exercised.

During the depths of the lockdown, I attempted working out at home, but it just wasn’t the same as powerlifting in the gym. I didn’t have the equipment, and more importantly, I didn’t have my community. I shifted to doing long walks and lots of yoga to maintain some level of physical activity, but it never provided the same fulfillment. I figured that I wasn’t alone in this.

So, I contacted my friend and colleague Dr. Katherine Rose Hejtmanek to see if she wanted to collaborate on a survey based study to see how exercise routines were disrupted by COVID-19, especially the stay at home orders. She immediately agreed, which lead to a wonderful collaboration that is resulting in three publications.

The first one just came out! This one focuses on the ways in which the stay at home orders revealed how exercise routines are a part of vitality politics (“vitality politics” of everyday life, or the “growing capacities to control, manage, engineer, reshape, and modulate the very vital capacities of human beings as living creatures,” Rose, 2007 page. 3).

In response to the pandemic, white, affluent women (who were the most common respondents to our survey) shifted their motivations for working out from one of pleasure to an almost business-like motivation. They were no longer working out for the joy/entertainment of working out and interacting with others, but did so to maintain some level of physical and mental wellbeing.

There is a great deal more in this article that touches on the intersections among race, class, body ideals, and politics – so give it a read!

Another article that has been accepted but not published yet examines how the COVID-19 pandemic differentially affected regular gym goers vs. CrossFitters. That should be out any time now. And the third article is a chapter in an edited volume – this one explores the ways in which women displayed greater resilience and flexibility in their exercise routines during the pandemic relative to men. Be on the lookout!!!!