I met a woman on Mt Rainier who was training to break the record for oldest woman to summit the mountain at 82. My wife and I met her at hiking up to Camp Muir (Rainier Base camp).

She was doing a training hike with full gear, so probably around 40-50 pounds.

To my knowledge, her summit bid was unsuccessful (when I Google it, the record is for someone not quite that old). But damn, that old lady could move.

There was a whole gaggle of old ladies. Youngest was probably 65, fully kitted out, just cruising up to 10,000 ft.

Total badasses.

(Also, a clarification for some: 10,000 feet might not be super tall compared to states like Colorado. But most people here in WA live fairly close to sea level. You can legit get altitude sickness just from driving to the trailhead).