Camp Muir is the main base camp for Mt. Rainer ascents and, at altitude 10,188 ft (3,075 m), is the mountain’s highest point accessible without a climbing permit. Reaching the camp, named after famed naturalist John Muir, requires a 4.4-mile (7 km) trek with an altitude gain of 4,639-ft (1,413 m), much of it across the Muir Snowfield.

We’d been wanting to make the hike for a while, but were a little nervous about taking it on as the climb is considered quite strenuous and we’ve read of several people who had “bonked” in the attempt. Bonking, or “hitting a wall,” is when the body’s carbohydrate reserves are depleted and energy levels drop precipitously, a state that can take many hours to recover from. To avoid that, we had loaded up on various carbs to consume as we proceeded. This was our first major hike wearing CGMs (continuous glucose monitor). It was an interesting little experiment and we learned a lot in seeing how our blood sugar responded to the exertion and the carbohydrate ingestion.

We’d rented a VRBO cabin for the weekend in Ashford, a roughly three-hour drive south of Seattle. We got a great preview of Mt. Rainier along the way, and enjoyed a leisurely dinner that night on the patio overlooking a small lake.

We got an early start the next morning at 5:30am, and hit the trail at 6:20am from the Paradise parking lot at elevation 5,400 ft (1,647m). The day was looking to be clear and calm, ideal for our hike. We had great views to Mt. Rainier and Mt. St. Helens as we ascended, and enjoyed some wildlife and colorful wildflowers.

We left the wildlife and wildflowers behind when we started onto the Muir Snowfield, just beyond Panorama Point at elevation 6,800 ft (2,074m). We already wore gaiters to keep the eventual snow from getting into our boots, but here we also donned the micro-spikes we bought in Norway to give us traction on the icy surface. The views got better and better as we proceeded, but for only occasional hikers it was a tiring slog.

We’d read that the last hour or so of the hike seems to go on forever, and it really did. The buildings at Camp Muir were visible, and tantalizing close, but we didn’t seem to be getting any nearer as we proceeded. Along the way, several people passed us glissading (sliding down the glacier in a seated position) back down the snowfield.

And, finally, we arrived at Camp Muir and the famous stone buildings we’d seen pictures of. Many at the camp were serious climbers preparing for an ascent of Mt. Rainier. A common approach is to make the hike we just completed, overnight at Camp Muir to acclimatize to the altitude, then take on the final ascent the following day. Several dozen tents were pitched on the snowfield behind the camp.

We were super-excited to finally have arrived, but pretty exhausted after the 4-hour, 4.4-mile (7 km), with its average slope of 20 degrees. Partly we were tired from the altitude gain of 4,639 ft (1,413 m), but also due to the absolute altitude of Camp Muir at 10,188 ft (3,075 m). We took our time resting for a bit and taking in the scene.

We found a quiet spot a short distance from the main buildings to enjoy a leisurely lunch with a fabulous view to Mt. Hood (at left in the photo below) and Mt. St. Helens. Unpacking our lunch, were amused to see how much a bag of mixed nuts had expanded with the altitude gain.

We’d brought our snowshoe poles with us, but hadn’t need them on the ascent. They were very useful on the descent, however, allowing us to make much faster time by slightly skiing downhill. We also tried sliding down along some of the glissade shutes. It was fun, but not very fast in the soft snow.

Returning to our cabin, we shed our hot climbing boots and enjoyed a cool drink on the patio before heading in for dinner at popular Rainier Base Camp Bar & Grill in nearby Ashford. We’d not been before, and were quite impressed with the food, facilities and live music.

Reflecting on the hike, several factors will contribute to how tired we felt. We’d been exercising fairly consistently for the past year, and expect we would have had a lot more difficult time making the ascent otherwise. But keeping our carbohydrate levels up was key. James often gets more tired than Jennifer on big hikes, and we’d mostly attributed it to lower fitness levels. But we learned on this hike, through wearing the CGMs, is that James seems to expend his glucose stores much faster than Jennifer.

Throughout the hike, we consumed vast amounts of carbohydrates: Cliff Bloks, apple sauce and Gatorade, plus RxBars, Kind Bars and That’s It Apple & Pumpkin mix. That sort of carb consumption would normally send our blood glucose soaring over 200mg/dL, yet James rarely rose much over 100 (a healthy maximum after overnight fasting). During the ascent, he averaged 106, while Jennifer averaged around 160. Below are James’ CGM graphs for the first two hours of the hike from 6:20am to 8:30am, left, and the full ascent from 6:20am to 10:30am.

And even on the 3-hour descent, as we continued to pump him full of carbs, James’ blood sugar never exceeded 108 until the last hour. As we returned to Paradise on the Golden Gate Trail, James’ blood sugar finally climbed into the 130s. In retrospect, we should have consumed more carbs before we started, particularly James, and we think he needed more carbs underway as well to stay clear-headed and moving at a reasonable pace. But fortunately we did consume enough, although just barely it would appear, to successfully complete the hike, and we were excited to have made the trip.

Our route to Camp Muir is shown on the interactive map below. Click here for a full-page map.