Sleeping on drifting sea ice in the middle of the Arctic Ocean might not seem ideal for a solid night’s rest, but for Annie Aggens, it’s all in a day’s work.
Aggens is an explorer with more than two dozen polar expeditions to her name. She’s certified by the International Polar Guides Association, the author of the “Encyclopedia of Outdoor and Wilderness Skills,” and the director of Polar Explorers, an organization that guides adventurers to some of the most remote and challenging environments on the planet.
Her first polar trip was to the North Pole in 2000, on a 10-day expedition. Since then, she’s been back an astonishing 10 times. She’s also led two expeditions to the South Pole (in 2007 and 2018), completed a 25-day trek across the Greenland Ice Cap, done several Vatnajökull traverses (Iceland’s largest glacier), and traveled to Svalbard, a Norwegian archipelago in the Arctic Ocean.
One of the few female guides in the world to have led expeditions to both poles, Aggens has spent two decades sleeping in temperatures as low as -40 degrees Fahrenheit. It’s not an easy feat, but with proper planning and the right gear, getting good sleep is achievable. Which is great news, since being rested is necessary for expedition success.
What are polar weather conditions?
Even though all polar regions are cold — like really, really cold — they differ when it comes to climate. Antarctica, home to the South Pole, is a solid landmass covered by ice. It’s the coldest place on Earth. “The South Pole is higher, it’s drier, and it’s colder [than the North Pole],” Aggens explains, “But because there’s a lot of solar radiation at the South Pole, there’s a lot more respite [from the cold].”
The North Pole is a different story. There is no land mass, just floating ice. “Even though the North Pole is warmer, it feels colder. It’s much more uncomfortable because you’re sitting on top of an ocean,” says Aggens, “So there’s a ton of humidity in the air, and it’s a very damp, cold feeling.” Not only do explorers have to deal with bone-chilling air, they also have to contend with unpredictable drifts as they traverse over the Arctic Ocean’s sea ice. “It’s common that you may be skiing north, [but] while you sleep overnight, you may be drifting south, so you’re repeating a lot of your mileage.” There are also diversions such as pressure ridges — layers of stacked sea ice stacked — as well as open water that you must either climb over or go around, adding even more miles to a trek.
Despite the differences, no matter where the expedition takes place, Aggens and her team are in a near-constant state of movement, pushing toward their goal, except when they sleep. A day of polar exploration is divided into four big tasks: breaking camp, skiing, making camp, and sleeping. When they’ve skied their miles for the day, they make camp, eat a warm meal, and bundle up for bed.
How polar explorers get sleep
Every day the team finds themselves sleeping in a new location. There are all sorts of things to consider when deciding where to set up camp, says Aggens, adding that the look, feel, color of the ice, and snow conditions all factor into the decision.
Like regular camping, polar explorers sleep in tents, only their tents are designed for the cold and snow. Tents used in polar regions need to be stormproof, so they’re constructed with heavy-duty ripstop fabric that can withstand strong winds, and they’re often double-walled for better insulation. They’re typically domed or tunnel shaped, with steeper side walls and plenty of room inside so that nothing is pressed against the walls; otherwise, ice crystals will form. They’re also highly ventilated for breathability and visibility, and they need to be easy to erect, since explorers are pitching their tents with thick gloves on.
Their other camping gear is optimized for cold weather, too. To stay warm in sub-zero temps, Aggens starts with two sleeping pads. Her first line of defense against the Earth’s cold surface is a closed-cell foam mat on the ground that she tops with an appropriately rated inflatable sleeping pad. Next up is her mummy bag. “I sleep in a -40-degree bag, and sometimes I even put a liner inside of that because I sleep very cold,” she says. She sleeps in the same wool base layer she wears for skiing.
Then, she uses a hot water bottle to warm up her midsection. Her core stays cold to the touch for a few hours after she gets into her sleeping bag, before the hot water bottle works its magic. She’ll also sleep in a hat, which she pulls down over her eyes to help keep in even more heat and prevent frost from building up. Her final piece of gear is a “little face protector that just keeps my nose warm because my nose can keep me up at night if it’s cold out.”
Her mouth is the only part of her face with direct exposure to the cold air. ”We can’t breathe into our sleeping bags because over the course of a few days, the bag will accumulate too much moisture, and that moisture will freeze. Our sleeping bags will become heavier and heavier and lose their insulative value quickly.”
When Aggens wakes up, her sleeping bag is covered in frost from the top of her head to her waist. She shakes the ice off, lays her sleeping bag out to dry, and prepares to keep pushing.
How much sleep do polar explorers get?
Similar to a regular night at home, eight hours of sleep is Aggens’ goal. “Sleep is super restorative, and if you consecutively don’t get enough sleep, your body starts to break down, you don’t heal as well, and your muscles aren’t regenerating as well,” she says. “In the cold temperatures, things don’t heal well anyways, so you need to give yourself all the benefits you can of downtime, sleep, hydration, and food. Everything you can give yourself, you need to give yourself.”
Fortunately, polar explorers are able to acclimate to their surroundings. “Humans adapt to living in cold environments by increasing their metabolism and insulation,” says Dr. Valerie Cacho, board-certified internal medicine and sleep medicine physician in Buena Park, California. “They shiver less and there is decreased blood flow to the fingers and toes in order to shunt warm blood towards the heart and vital organs.”
Best sleep is attained in what Cacho refers to as the “zone of comfort,” a homeostasis of 60 to 70 degrees Fahrenheit. “Deviations from this — either too hot or too cold — can disrupt the quality of sleep a person has,” she says. Even so, sleep comes pretty easy after skiing for a full day. “For most people, it’s no problem to fall asleep because we are knackered,” Aggens says.
But that all gets kicked out the window if the team is racing to catch a plane or fighting against drifting sea ice. Like most athletes with an eye on the prize, polar explorers must be willing to push through, even if that means compromising sleep. “I’ve skied 30 hours without any sleep at the North Pole,” Aggens recalls. “We would typically never do something like that, but if you’ve gotta do it, you gotta do it.”
If explorers miss an opportunity and end up on the “backside of the drift,” they can drift away from the North Pole faster than they can ski. “It’s happened to us on a few occasions,” says Aggens. “You can get within 10 miles of the North Pole, and no matter how hard you ski for however many hours of the day, you won’t make it.”
The Arctic and Antarctic challenges that make sleep difficult
While the South Pole is fairly predictable, North Pole ice can crack underneath sleeping explorers. It’s not common, but it can happen. “I’ve moved my camp once because of ice. We woke up, and there was a big lead [waterway] 10 feet away from our tent that wasn’t there when we went to bed,” Aggens recalls.
There’s also one particular animal you don’t want to have a run-in with: a polar bear. Polar bears live in the Arctic, on floating sea ice. It’s a remote possibility but not one to take chances with, which is why Aggens doesn’t sleep very deeply at the North Pole. “For me, it’s a super shallow sleep because you’re on sea ice, and you’re constantly [assessing] every single sound,” says Aggens. “[They’re] the only triggers that you have. So you tend to be very alert to sound when you’re in your tent at night.”
As Cacho explains, “People who are in hypervigilant and hyperaroused states can have disrupted sleep. Sleep occurs when our brain waves slow down, so if there is a stressor or fear on our mind or in our environment, it can affect the quality of sleep.”
If there’s an active bear situation, or the potential for one, explorers will rotate posts, sitting outside in shifts of one to two hours. Aggens has only had one close encounter with a bear, but she’s no stranger to bear watch. On a recent ski expedition to Churchill, Manitoba — a Canadian sub-Arctic location where polar bears outnumber people — Aggens’ team had bear rotation every night of their seven-night expedition. Waking up to stand outside for an hour or two in the cold is tough on even the most seasoned explorer. “That is just a massive sleep zapper. The next day your performance is down because you haven’t slept,” explains Aggens.
Even if there are no bear encounters, the Arctic is a stressful place to station yourself. “Your mind is thinking about all the various options, and your body’s prepared to react — and it’s prepared to react the whole time. It’s exhausting. And then you don’t sleep.”
How polar explorers return to normal sleep post-expedition
When an expedition is over and Aggens returns home, she’s faced with a couple of unique challenges as she settles back into her regular sleep routine. “A lot of us have night sweats,” Aggens says. “I think that our [bodies are] so used to producing a lot of heat to stay warm that when you get into an environment where your body doesn’t need to do that, you wake up totally clammy for a few nights.”
“This is due to vasodilation,” Cacho told us. “When someone is back in warm temperatures, the blood vessels to the nonessential organs like skin, fingers, and toes open up, which results in sweating. It is a form of restabilizing the circulation of blood in our bodies.”
Then, there are vivid dreams. Aggens is in charge of leading groups in these polar regions, which requires her to constantly assess conditions and make important decisions for the safety of everyone. That responsibility can take some time to shake off, especially after an intense journey. “I will wake up in the middle of the night and be in a panic because I don’t know where I am, and I don’t know what’s going on with my team,” she says, before quickly realizing that she’s at home in her bed.
Despite all the challenges with polar exploration and the mental and physical strength it takes to succeed, Aggens feels fortunate to do what she does. “We’re in these places that are so extreme, and at the very same time, they are so delicate. It’s such a privilege to be able to go there, and we have such a responsibility to be the voice for [them].” Even if that comes with sleeping next door to a polar bear, which for Annie Aggens, is just another day at the office.