Man, sometimes I think I could use a drop in libido. Maybe it would let me focus on my career a bit more, like Costanza in that Seinfeld episode. So far, young as they are, my thirties haven't slowed me down at all compared to my teens or twenties. If I could get out of the gym and out of the bedroom I would literally save hours per week of precious time.
I'm 36 and feel the same way. -not the gym though but I do exercise a good bit. I think if that went away I'd miss it. I think it's the same type of energy, sexual and physical that helps me be productive. Maybe they can't exist without one another. No sex drive = planting your butt on your chair, watching baseball and drinking Wild Turkey, resting your face on your cane. -Actually, it doesn't sound half bad :)
Sarcasm aside, this is why narcissism is not always a bad thing. Deeply caring about the way you look provides excellent drive. As long as it's directed towards healthy methods of physical "improvement," you're going to be hard put for better sources of inspiration/motivation when it comes to exercise, eating right, self-preservation, etc. Oh, sure, you could say longevity, but we respond to what's right in front of us. I exercise and eat well because I want to look good today and better tomorrow. Long-term quality of life? That's icing. Or sprinkles. Or when you eat the cake and beneath that, there's more cake.