Reindeer Herder Total Energy Expenditure…Reindeer Herders Work Hard!

I am excited to share our new publication about Reindeer Herder total energy expenditure (TEE, kcal/day)! This work is the result of a collaboration with Dr. Päivi Soppela, Dr. Minna Turunen, Ville Stenbäck, Dr. Karl-Heinz Herzig, Dr. Rebecca Rimbach, and Dr. Herman Pontzer. We measured how many calories the reindeer herders in sub-Arctic Finland expend and consumed during an exceptionally busy time of year…the autumn herd roundup. We also included some pilot data from a much less busy time in the spring.

The herd round up consists of collecting reindeer from their summer pastures either on foot or with the aid of all-terrain vehicles, motorbikes, snowmobiles, or helicopters. During this time, herders count the number of reindeer, separate the animals to be left alive from those to be slaughtered, mark calves with the owner’s earmarks, and return any wayward reindeer to their proper owners.

A picture of the 2019 autumn herd round up. Photo taken by Dr. Minna Turunen.

Here are some of the key findings:

Herders are very active during the annual herd roundup!

We measured TEE using two methods: the gold standard doubly labeled water technique and the flex-heart rate method. During the herd roundup, herders expended a mean of 4183 ± 949 kcal/day with female TEE ranging from 2898-3887 kcal/day and male TEE ranging from 3463-5853 kcal/day. There was no significant difference between the two methods.

Herder total energy expenditure by sex and measurement method

Herders eat way fewer calories than they burn during the roundup, and their diet is relatively high in fat.

Females consumed 883-2195 kcal/day and males consumed from 854-3638 kcal/day, which is well under the number of calories they were burning each day. Diet information was collected via diet diaries, and this can be a rather inaccurate estimate of calories consumed. However, even if herders underreported calories by as much as 20%, they still would have expended ~1000 kcal more than they were consuming each day during the herd roundup. The herders’ diet consisted of a greater proportion of protein and fat than is recommended by the World Health Organization (WHO).

Herder diet composition (right) compared to WHO recommendations (left)

Herders expend a similar number of calories to farming economy populations like the Aymara speaking peoples and Shuar…at least during the herd roundup.

We compared the herder total energy expenditure to that of hunter-gatherers, farming economy populations, and market economy populations. Herder TEE was significantly higher than hunter gatherer and market economy populations, but very similar to that of the farming populations. However, herder TEE was much lower during the spring pilot study, though May is a particularly less busy time of the herder year.

Log TEE vs. Log Body Mass Regression. The herd roundup is represented in bold red and the herder spring pilot study in bold black.
TEE residuals for each of the comparative populations

Given exposure to extreme cold in addition to high physical activity levels, one might expect herder TEE to be significantly higher than, rather than equivalent to, equatorial farming economy populations with similar activity levels but a potentially reduced thermoregulatory burden. There are several potential explanations for the similar energy expenditure among the herders and the farming economy populations, all of which highlight how local ecologies and biologies likely play an important role in shaping energy expenditure.

  1. Herders are very good and very experienced at mitigating cold stress – using technology, alternating tasks, and eating warming foods, for example.
  2. The herders’ high levels of physical activity may help reduce the cost of trying to stay warm in their cold climate.
  3. The farming economy populations are also known to carry a high parasitic burden (though cold climate populations have their fair share of such burdens, too, though not to the degree of equatorial populations). This high parasitic burden can raise energy expenditure in the way that the need to keep warm may raise energy expenditure among the herders.

What’s Next?

Well, we are applying for funding in hopes of expanding TEE measurements across seasons to get a better, more detailed view of energy expenditure across the herder work year. We would also like to expand the number of participants, and begin to look at the impact of climate change on reindeer herder TEE and other physiological measures.

Cultural Cold Climate Coping Mechanisms among Reindeer Herders

Our new paper in ARCTIC is out! This paper looks at the cultural cold climate coping mechanisms among the reindeer herders we worked with in 2018 and 2019. We discuss different coping behaviors that range from physical activity style decisions, ecological knowledge, technology, clothing, food, and more!

A picture from this paper was also chosen to be the cover of the upcoming ARCTIC Issue.

Please contact me for a PDF!

Dare To Be Human

I recently had the opportunity to be on the Dare To Be Human podcast that is hosted by Kat Koppett and Livia Walker who I was fortunate enough to get to know and befriend during my time in Albany, NY. They are a part of the Mop Co Improv Theatre, where my husband did improv for almost three years. They were also essential to the improv and anxiety study I conducted with colleagues.

I thought this interview was going to revolve entirely around that study, but it didn’t! It was perhaps one of the most wonderfully wide-ranging interviews I have ever been a part of. I touch on a number of topics that are near and dear to my heart, and I am so grateful to Kat and Livia for giving me the time and space to discuss them.

Have a listen here – I hope you enjoy!

Rock and a Cold Place: Neanderthal Biocultural Cold Adaptations

Comparison of a female Neanderthal to a female anatomically modern human. Illustration by Morgan Zepf

My review paper on Neanderthal biocultural adaptation to cold (email me for a copy), written with the amazing Dr. Sarah Lacy and Alexandra Niclou, came out today!

This paper was born out of a poster (link to file below) I and Alex made for a special American Association of Physical Anthropology poster session held to celebrate Dr. Erik Trinkaus‘ career. It was a wonderful session that gathered together all of his students.

A picture of Dr. Erik Trinkaus and many of his students. A truly wonderful celebration of his career and impact on the field.

For this poster, we wanted to talk about the different mechanisms that may have been utilized by Neanderthals to survive and thrive in cold climates. While making this poster, we realized that there was no paper that brought together the anatomical, physiological, and cultural evidence of Neanderthal cold climate adaptations. So, we decided to write one! We brought my friend, colleague Sarah Lacy in on this as Neanderthals are her area of expertise, and we got to work!

This paper puts in one place the variety of different cold climate adaptations Neanderthals may have had. Furthermore, we identify ten different areas we think should be the focus of future research.

I adore this paper for many reasons:
1. This paper provided the opportunity to collaborate and write with two brilliant women who I adore. Writing with them was a joy, and we worked incredibly well together.
2. The the image of Neanderthals and Anatomically Modern Humans depicts females…such a rare thing. This figure was also drawn by an undergraduate student of mine, Morgan Zepf.
3. It has an awesome reference list! The original draft had 275 references, but had to cut that down to 100 to fit the journal guidelines.
4. This will be a great paper to use in undergraduate classes!
5. We hope this paper will guide and inspire future dissertations.
6. I started writing this review on my Spring Break 2020 where I went to a cabin in the middle of no where and just wrote. When I emerged from this writing retreat, the entire world had gone on lock down due to the COVID-19 pandemic. This paper will always hold an odd place in my memory because of that.

The research that keeps on giving

Every winter for the past four years I have been interviewed about my work in cold climates, and in particular, what the benefits of exercising in the cold may be. Each year, I think the call for interviews for stop. Each year I am wrong.

However, this year might be the biggest outlet yet, – Washington Post! I was very excited to do this interview, and Christie Aschwanden did a fantastic job! I could have chatted with her for hours, and I am incredibly grateful to her for taking my ramblings and making them something coherent.

Improv & Anxiety

We got a nice little write up by PsyPost about our work looking at stress, anxiety, and absorption among comedy improvisors.

I always enjoy doing interviews or answering questions, but I always get very personally anxious about it. Once you put the information out there, you lose control of it. However, Beth Ellwood at PsyPost did a great job.

American Journal of Human Biology Editor’s Choice

As I have posted about the article before, I won’t go into details, you can find those here. However, I am delighted and proud to share that my article with collaborators Dr. Minna Turunen, Dr. Päivi Soppela, Ville Stenbäck, and Dr. Karl-Heinz Herzig was selected as the Editor’s Choice article for the 32(6) issue of the American Journal of Human Biology.

A photo Minna took was also selected to be the issue cover photo!

COVID-19 Impact on Gym Lifters

This was our recruitment poster

Back in May during one of the many peaks of the COVID-19 pandemic and stay at home orders, I was feeling useless. I felt the need to contribute and help. I also was personally feeling terrible since I wasn’t able to maintain my powerlifting routine. I decided to combine the two.

I got in touch with my friend and colleague, Dr. Katie Rose Hejtmanek, and we put together an online survey looking at gathering information on how the stay at home orders affected exercise routines. Furthermore, we wanted to find out how the changes in routine also affected perceived physical and mental well being.

We quickly got over 500 survey respondents, and it became very clear that folks who almost exclusively used gyms before the pandemic faired the worst during the stay at home orders. We have not published these results yet, but wanted to put something together in hopes of getting results back as quickly as possible to out participants as well as providing some techniques for coping.

Here is the infographic we created based on the preliminary analysis.

Thanks to all who participated!