several hours of exhausting exercise
I agree, my personal record was 4 hours 20 minutes of non-stop action. I was astonished how cruelly fast the time is running. And I'm not that young, it's all about woman and Viagra / Cialis. ;)
The woman have to be passionate, that is the key. It's all about your partner and your lust. Smoking and alcohol may affect the process, it's one of the reasons I stopped drinking. And I have a weak heart, that is the main thing all men should be aware of. I think I would die because of my heart, but hopefully doing something energetic, poor woman though.
Anyway I strongly suggest to check the heart every year, abstain from salty foods, lesser the sugar consumption and forget about bad habits, and enjoy natural love ;)