I had a similar experience when I was in my "prime" along with a couple buddies in the Trinity Alps. As we sat in camp treating our aches and pains with Vitamin I (buprophen) and a bourbon at the end of the day, along came a couple young women over a more difficult pass, on a longer route than we took with heavier packs than ours. After a short conversation, they headed up another 800 feet to camp at a higher lake. Next morning they kept going over a very steep off-trail pass. We felt like whimps day hiking up to that lake the next day.