I can tell you, your proposed pack weight separates the men from the boys. 15 years ago (45 y/o at the time; 160 lbs; average physical condition), did a High Sierras hike, just below Yosemite, totin’ a 50 lb. pack: 16 miles roundtrip; 4,000 ft. elevation gain; moderate to fairly strenuous terrain; one day in; 3 days at destination; one day out. Despite the fact I was a moderately active weekend backpacker, the pack-weight made the trip less enjoyable. More rest stops than usual.
Afterwards, replaced some gear with new, lighter stuff (sleeping bag, mess kit, stove etc), and took a hard look at my gear list (Do I really need to carry this?). Sliced 15 lbs. off my typical pack weight. It made a difference, and my body appreciated it. Like Hghvlocity said: “Conventional wisdom says a maximum of 1/3 your body weight.” Same school of thought says for long-distance hikes, pack weight shouldn’t exceed 25 percent of body weight.
Maybe you’ve seen some form of this example; probably not totally scientifically accurate, but you get the point: average person covers a mile in 2200 steps; you lift your pack weight every time you lift your foot; ten pounds in the pack is 22,000 lbs. lifted over the course of a mile.
As others suggested, put it to the test. Throw it on your back, and take it for a spin; and, importantly, on terrain comparable to what you’d expect to cover in a “situation.”
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"Things that have never happened before happen all the time." — Scott Sagan, The Limits of Safety