... you know the difficulty of telling someone "don't get distracted" or "don't procrastinate"? It won't work. It's the same with me and exercise, I agree with you on an intellectual level, and I'm well aware of the dangers of my unhealthy lifestyle. But I just can't find the motivation to do it.
Like I replied elsewhere, I would definitely do trekking or biking if I lived in a place more suitable for those activities. I enjoy trekking and walking when I'm on vacation (my vacations tend to involve lots and lots of walking).