How about yoga? I would have thought that some basic exercise would be encouraged to protect the back, legs, etc for practice in old age.
"I do not perceive even one other thing, o monks, that when developed and cultivated entails such great happiness as the mind" (AN 1.10, transl. Ven. Bhikkhu Bodhi)
"So this spiritual life, monks, does not have gain, honor, and renown for its benefit, or the attainment of moral discipline for its benefit, or the attainment of concentration for its benefit, or knowledge and vision for its benefit. But it is this unshakable liberation of mind that is the goal of this spiritual life, its heartwood, and its end," (MN 29, transl. Ven Bhikkhu Bodhi)