Sunlight could "turn off" their abilities.
In that vein, yes, but building up semi-permanent histories of choices made and consequences thereof.
Do you know who
Kurt Hahn, the founder of Outward Bound was? He used to talk about seven forces of decline that affect the modern world: decline of fitness, care, skill, initiative, self-discipline, imagination, and compassion. All of which are functions of experience.
Now, the funny thing is we associate most of those declining quantities _but_not_all_ with *lack* of being out in sunlight. Now flip that. Imagine a tennis champion vamp, who, the more he plays outside, gets weaker, less imaginative but also crueler, while at the same time less assertive. That's right, sunlight makes him into a cheap weak bully.