During the winter of 2019/2020, I embarked on an ambitious 30-day expedition to the interior of Antarctica. The goal was not only to complete the last of the Seven Summits, but also to research female physiological responses to prolonged polar expeditionary travel. From the start, the trip was beset with obstacles and setbacks, but in the end, all three of my objectives were accomplished:
- Ski to the South Pole (12/28/19): Took a week of skiing 8-14 hours a day while hauling a heavy sled, temps as cold as -40 degrees C, all of it above an elevation of 9,000 ft.
- Summit Vinson Massif (1/6/20): Completed the Seven Summits! We had terrible luck with weather and ended up trapped at high camp for several days, turning what’s normally a week-long expedition into 15 days. Food rationing and frostbite made this climb particularly tough. I’m okay now, just some minor frostbite on the toes, but still scary.
- Summit Mt. Sidley (1/18/20): The highest volcanic peak on the continent and one of the most remote peaks on Earth. Climbed by fewer than 50 people. Beautiful and isolated, we camped out with the plane that brought us the 600 miles from Union Glacier camp until we made our summit bid.
In retrospect, being nine months down the road from my longest-ever expedition, I realize now just how much I have learned from the experience. It was an adventure in every sense of the term. Survival instinct, mental toughness, and resilience all took center stage as I stretched my capacity to tolerate discomfort and uncertainty nearly to the limit. Here’s what worked, what didn’t, and what I’d do differently if I had to do it all over again. Oh, and also a bit of the science for my fellow number geeks.
- The WarmCube™ gear and the custom Marmot polar gear was a lifesaver. I wrote a recap for the team at HQ shortly after my trip; here are some excerpts:
- Custom Gear: It was amazing! During the ski, the down skirt was the envy of my teammates and it saved my butt (literally). Such a key piece of this trip. Also, the ruff we attached to the hood of my Huntley shell proved invaluable. It’s incredible how well it keeps the wind from getting at your face. Game changer. I am so grateful to Aubrey, Maria, and the rest of the team for these custom items!
- WarmCube: The West Rib Parka was a life saver. I wore it every single day. In camp, during breaks from skiing/climbing, as a sleeping bag one time… The large and numerous pockets were key for stashing all my necessities (nutrition, sunblock, Garmin InReach, trash) at each break. The warmth was felt the second you put it on. Also, it’s really durable; I wore it while descending fixed lines on Vinson using an arm wrap technique on the ropes which could have easily worn through/damaged less durable materials. Lots of friction involved. But the West Rib held up perfectly.
- 8000-Meter Mitts: I’ve never been able to wear heavy mitts during climbs and maintain dexterity until now! Wow, these are great. The down insert gloves I wore often alone during the ski, and I threw on the outer mitts when it got really cold. I was able to use them on the fixed lines on Vinson…no problem opening carabiners and clipping/unclipping through transitions/anchors. Hard to believe how well these worked. Well done! So warm, too. I think between my simple liner gloves and these mitts, I was covered nearly 90% of my expedition.
- Mt. Tyndall Synthetic Insulated Pants: It was great to have these to throw on during the day when the wind came up and dropped temps instantly. The full side zips made this easy. Super warm but very packable. The best insulated pant I’ve tried to date.
What didn’t work
- I blew through my planned nutrition early on in the trip due to our prolonged stay on Vinson, and ended up rationing food, running out, and then living off of candy bars shared with my tentmate for several days. The subpar nutrition not only made me feel awful, it ultimately resulted in some thyroid issues that I’ve since had to correct.
- In my packing frenzy, I somehow forgot my 8000-Mmeter boot liners and had to borrow some that didn’t quite fit right, which eventually resulted in me getting frostbite. Big-time fail. I’ll never leave without first checking inside my boots before an expedition. Lesson learned, the hard way.
What I’d do differently
- Bring more food (!) and pack additional devices to measure physiological data (ketones, continuous glucose monitor, salivary cortisol, my portable metabolic cart). Because you can never collect enough data.
- Bring entertainment options for days stuck in the tent. It was never an issue on previous expeditions, but in Antarctica I did a lot of lying in wait. Luckily, my tentmate also shared his entertainment options with me, and we were able to watch some movies to pass the time. (Secret Life of Walter Mitty, it’s a must-see if you haven’t).
The Sciency-y Bit
- Metabolism: Needless to say, with all that skiing and climbing, I burned through a ton of calories. While my average daily energy expenditure was a modest 2,330 calories, that figure included several days spent entirely in the tent resting to conserve energy. The highest daily burn, during which I skied 14 hours pulling a heavy sled for the final push to the South Pole, was a whopping 5,150 calories, or about 2.5 times what I normally eat in a day. To put it in perspective, that’s the caloric equivalent of eating 17 cheeseburgers, or 25 Hershey’s milk chocolate bars.
My average energy intake was about 2,000 calories daily, until we ran out of food. Then it became more like 600-800 calories, not even a sufficient amount to fuel my resting energy needs, which are roughly 1,400 calories daily at sea level. Keep in mind, resting energy needs increase with both altitude and cold exposure by as much as 30%, meaning my resting (not moving or anything) energy requirements were more like 1,800 calories.
- Heart Rate Variability (HRV): A snapshot of how well your body is handling stress, HRV measures how variable the time (in milliseconds) is between successive heart beats, which gives an indication of how ready you are to handle stressors such as physical activity. Higher values are considered better on this measure, meaning more variability and more tolerance to additional stress. Mine is normally in a range of 150-250 ms. The average recorded in Antarctica was 67 ms. The lowest recorded value was 11 ms, the day prior to my departure. My body was in desperate need of some recovery time.
- Lasting Metabolic Impact: I noticed my body temperature was slightly higher than normal, which seemed counterintuitive considering the cold environment. However, when you are exposed to cold temps for a long time, your body upregulates its internal heat production, known as “non-shivering thermogenesis” in an effort to keep you warm. So, you become a little furnace, essentially. This takes a lot of extra energy, and under conditions of limited caloric intake (food rationing) can throw thyroid levels off and lead to hypothyroidism (underactive thyroid). It’s like your home thermostat being out of whack. It thinks it’s getting too hot, so it stops running the heat after a while until the room cools down, but the temperature gauge is wrong so it ends up staying off for too long, leaving your house feeling like an igloo. That’s pretty much what happened to me after Antarctica. My thyroid levels dropped below the normal range, and with them, so did my energy. It took several weeks to correct.
- Implications for Future Research: It would be interesting to measure with more specificity how much a woman’s basal metabolic rate increases in response to combined cold and altitude exposure. Based on military research in men, current estimates are as much as two to three times the rate of sea level conditions. From examining my data, I calculated that mine was more like 1.5-1.75 times sea level values. This is something I plan to measure with a portable metabolic cart on my next expedition (a metabolic cart uses your expired breath to calculate caloric burn and what proportion of those calories come from fat versus carbohydrates). I’m looking forward to the day when international travel becomes safe again so I can get back out there!
In the end, if we don’t learn from our mistakes, we are destined to repeat them. It’s safe to say that I learned a lot of valuable lessons on this trip. I also found some new avenues for research that will carry me forward and shape the future of my PhD work. It’s hard to believe that it’s been nine months since I left my home in the Bay Area, with three duffel bags packed for adventure. I never made it back to the Bay, and I’m still living out of those three duffel bags (long story short: Covid). I’m finding that I don’t need much to survive and thrive. It’s a vagabond life for me at the moment, and I kind of like it that way. I guess the moral of the story is stay curious, seek your answers, and be open to wherever that road may lead you. Often, it’s the toughest lessons learned that cause you to grow the most.