It’s all about protecting your brain from possible stroke or other brain injury from it. Your balance isn’t the best - add dripping walls and it’s ripe for life alert.

Some drugs increase heart rate dramatically - the older you are the more susceptible to atherosclerosis or other circulatory diseases. There’s more medical risk the older you are for sure. However, you may find you only need a little bit. Some drugs are funny. Some work on first try, other takes a couple tries before your brain understands the chemical.

Otoh, the cost of hurting yourself in your 20s is way higher than the cost of hurting yourself in your 70s.

If you're a US male, average life expectancy ~76 years, then hurting/killing yourself in your 20s you lose ~50 years of life. Hurting/killing yourself in your 70s, you lose an order of magnitude less.

I hope to remember this in my 70s! Seeing most people don't, so not having particularly high hopes...

The err in your logic is that you care what you lose after you’re dead. You don’t. My point isn’t about death per se, it’s about overcoming adverse effects. Which is easier to do when you’re young and healthy.

Having a mini stroke at 26 like I did, I was able to bounce back. Having a mini stroke at 81 like my father did, resulted in his death.

Something about this logic feels funny to me - imagine telling two people clinging to a rock wall above a pit that the one at the bottom and very close to falling in has less to lose trying a risky move?

This logic is very common in rock climbing circles, yes. Many stories of people who stop doing dangerous sports once they get kids.