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A Foreword: Where I am Going and What I am Doing

May 18, 2011

This blog will be a documentation of the next seven months of my dissertation research and field work. I am doing this in part for myself so that I keep a log of all the adventures and stories I will accumulate. But I am also doing this so that any of you who are interested will be able to keep informed about my work and travels. So, let’s start with the basics, and sorry for the long first post, the rest will be shorter I promise.

The past several months have revealed that my friends and family really have no idea what it is that I study. This is entirely my fault and due in large part to me not really wanting to talk about my project for fear of it not coming to fruition. Well, now everything is in place, some grant money has come through (thank you NOLS and Leakey Foundation), and I am leaving this coming Monday, May 23, so it is high time I shed some light on my dissertation research.  I am currently working on earning my PhD in Anthropology, this is common knowledge to most, but I like to emphasize this since the scope of my research is rarely viewed as anthropology. For the big picture of my dissertation, I am looking at human metabolic rates in different climates, and producing a new model for better predicting metabolic rates (calories per day) in a variety of environments. The currently used model for such predictions is actually quite terrible. It consistently underestimates the amount of calories humans use, and this underestimation can be as high as 30% among highly active people.

Since, this model is used to determine the number of calories people use; it is also used to determine the number of calories people need…optimal diets. This can be quite a problem when calculating the optimal diet among many third world populations who are already not getting proper nutrition, but governmental organizations are not even able to recommend the right amounts given the poor quality of the model they use.

So, my overall goal is to measure metabolic rates among a group of highly active people, and use that data to test the new model I have built for predicting metabolic rates. The hope of course, is for my model better predict human metabolic rates in a variety of climates. Then, the anthropological goal is to use this model to make predictions for any population of living humans and even apply it to past humans such as Neanderthals.

 Where I am Going

I will be working closely with the National Outdoor Leadership School (NOLS) which is a school that teaches its students wilderness skills, leadership, and environmental ethics. Basically, students taking part in NOLS courses go up into the mountains, or the Australian Outback, or Patagonia (just to name a few) and live in the wilderness for 1-2 months at a time. They are exposed to the elements, take with them only what they can carry on their backs, and take part in rigorous physical activity such as mountain climbing, hiking, skiing, and kayaking.

NOLS Logo

The NOLS international headquarters is located in Lander, Wyoming. It is there that I will set up my home base for the next seven months. I will be collecting data from NOLS students taking part in semester long courses in the Rocky Mountains…specifically the Wind River Range. I will collect data on 4 semester-long courses, two in the Spring/Summer and two in the Fall/Winter. This allows me to collect data on all four seasons to incorporate that climate variable into metabolic rate predictions, and determine if cold climates produce the highest metabolic rates, temperate the middle of the road rates, and hot climates the lowest. However, between us, I believe that hot climates will produce metabolic rates higher than temperature climates.

Why NOLS?

You may say to yourself that my subject pool seems slightly contrived…and why not work with some traditional population? Here are the reasons why:

  1. Working with NOLS students in one location (domestic location) over a long period of time is cheaper and lets me collect data on temperate, hot, and cold temperatures – all of which they would be exposed to. If I were to work with a traditional population, it would be far more expensive travel and I would be limited in climatic variability. Working with NOLS allows me to collect all the data I want within a PhD dissertation budget.
  2. The setup of this project also allows for a neat control. Since I am looking at two semesters, each of which cover two seasons, each subject will be able to act as their own control. I will be able to compare the temperate metabolic rate in each person to their metabolic rate in either a hot (Spring/Summer semester) or cold (Fall/Winter semester) temperatures. This will help cut down on individual differences in metabolic rate when trying to compare the hot or cold metabolic rates to the temperate metabolic rate.
  3. By using a US population, I eliminate language barriers, cultural aversions to the techniques used, and possible cultural aversions to a female researcher collecting data among both male and female subjects. This too saves money by not having to hire a male research assistant and a translator.
  4. The NOLS subject pool provides not only exposure to a variety of environments, but also provides a physically variable group of people. Another part of my work looks at the role of body shape and size has on metabolic rates in different climates. Current thought (Allen’s and Bergmann’s Rules for those interested) is that people who are short and broad are better adapted to cold environments such that they will expend fewer calories in the cold than someone who is long and more narrowly built. This is based on surface area theory that the short and broad person (imagine a stereotypical Eskimo body type) has less skin surface area exposed to cold temperatures than the long and narrow person (imagine a stereotypical Sub-Saharan African body type) meaning there is less area for heat to escape. The opposite is true in hot climates; the high surface area of a long and narrow person confers higher surface area for heat to dissipate allowing them to expend less energy to cool himself than a short, broad, low surface area person. Study one traditional population would limit the amount of variability in body shape and size. The NOLS population provides greater body shape and size variability allowing me to explore the validity of Allen’s and Bergmann’s Rules among humans.
  5. Finally, the NOLS students are super excited about this project, which makes them willing and motivated to participate despite the large amount of time and effort I will be demanding from them.

The Data Collection Plan

I will take a whole suite of measurements on my subjects before they head up in the Wind River Range for their NOLS course. I will look at the body segment lengths, weight, percent fat, muscle mass, basal metabolic rate, and exercise metabolic rate. I will measure all of these things again once they return from their course, so I can see how measurements changed during their rigorous NOLS course and also to have the proper details for my model. Once I collect the Pre-Course measurements I leave the students alone for two weeks on their course so they can acclimate to their environment. After that two weeks is up, I will then hike out to their position in the mountains to assess the activity level, energy expenditure (daily metabolic rates calories/day), and diet. I will measure activity levels using heart rate monitors and student kept personal logs about distance traveled and activities performed. I will measure energy expenditure using the heart rate monitors and something called doubly labeled water (DLW). DLW is basically just heavy water; it has an extra neutron on one of the hydrogens and an extra neutron on the oxygen. Subjects will drink a dose of DLW and I will collect urine samples from them every couple of days for 1-2 weeks. DLW is perfectly safe and can be given to babies. The way it works is that, every time you metabolize food you use water from your own body water stores. The water broken down into oxygen and hydrogen. The oxygen is excreted both through carbon dioxide (when you breathe out) and through water. The hydrogen, however, is only excreted through water. So, by following the concentration of that tagged hydrogen in urine samples over several days, I am able to see the rate at which that hydrogen is being excreted (using mass spectrometry). That hydrogen excretion rate is related to metabolic rate. Yes, I know far more weird sciency details than you want.

Me pipetting urine samples

Finally, since the students have to pack all the food they need, they are able to keep very detailed diaries of the food they consume.

Additional Projects…at least the ones for now

A lot of fun projects are spinning of this such as nutritional needs of NOLS students. NOLS used to think their students were getting exactly what they needed while on a course. However, my pilot study last summer suggested they were not. I found that male NOLS students were losing a significant amount of muscle mass during their course. Now since many of these students are super fit to begins with (7% body fat for example) they have little body fat stores to rely upon, and so their body turns to their own muscle to support their high levels of activity. One way to prevent this is to include higher levels of protein in the diet. After I shared this data with NOLS, they have now put together a committee to look into some of these diet issues.

Another project I will be working on is pinning down the best way to estimate the cost of hiking up and down hill while carrying load…a heavy backpack. So, that is something else in the works.

End of The First Post

I will end for now with close to three pages of a first post. I do hope you enjoy reading about my work and travels; I certainly enjoy sharing. To all my friends and family, I will miss you dearly while I am gone, and I hope that we will all use this blog to keep in touch.

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5 Comments leave one →
  1. Kay permalink
    May 18, 2011 9:15 pm

    This is a great intro to your work. Thanks! Glad you are keeping in touch with all of us.

  2. jessica permalink
    May 18, 2011 9:58 pm

    Had I known that studying metabolic rates would have allowed me to live in one of my favorite cities in the world (Lander, WY), I probably would have been a phys anthro instead of a med anthro. 🙂 Sounds like a stellar project with great justification.

  3. Kelly O permalink
    May 18, 2011 10:15 pm

    Wow, this sounds amazing! I am excited to see how everything goes for you!

  4. Sarah L permalink
    May 18, 2011 11:25 pm

    This is a great way to document your journey. I am expecting lots of photos! Kisses and luck!

  5. Abby S permalink
    May 19, 2011 11:00 am

    Cara – This sounds amazing. Do you need a research assistant?! Good luck with it all. I’m looking forward to the updates!

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