How much should training increase stats?

So there has been talk every so often of allowing your characters stats to increase though training or just though their more phisically active live style. This already happens in the form of you getting fitter and thus higher both long term (weatiness) stamina and higher short-term stamina.

What however would be reasonable gains for the other stats in the game. By how much could a character expect to increase their strength stat for exemple just by being phisically active and bashing in heads? By how much could dex reasonably improve do to better coordination, balance, physical fitness and flexibility?

Could states like per and int be improved? Perseption could be increased do to your character gaining much better situational awereness. Regular exercise is benificial for your eye health and eyesight. We know that getting more education and knowladge does increase your IQ (kristalized) even in adults. Would the increase in knowledge and strengthening of certain mental functions coming from learning advanced programming and chemistry to a non-highly educated person warrant a increase in int? Could we assume that the multitude of new problems that a person would be faced with after the end of civilazation and them having to constantly use their mental facalties inorder to survive improves those facalties to the degree that it would require a increase in int?