Traditionally, we mortify the flesh, not the soul, and as Cor_ad_Cor notes it is to be done carefully and safely.
But, then again, there may be better approaches to “giving up” something…what is sacrificed has to be more meaningful than not eating chocolate, or not drinking coffee, or not spending so much time on the internet…sacrifices come in many forms…of course the three legs of the Church’s Lenten observation is almsgiving, fasting, and prayer…so if we are “giving something up”, maybe its money, food, and time, or some combination…I know several years ago, I figured I would spend $40 a month on coffee, so I decided to donate that $40 to Catholic Relief services, which I have continued to do month after month…and fasting sometimes consists of walking out of that fast food restaurant with a bag of food, and simply giving it to someone who looks hungry instead of eating it myself, and prayer takes sacrificing time…several lents ago, I put the TV remote on top of a bible on the coffee table…and instead of empty minded channel surfing, if I didn’t know exactly what I planned on watchng, I moved the remote aside and spent some time reading and praying scripture.
Lent is about conversion…and conversion is about change, so maybe what you change will carry on beyond Lent, and conversion will be continual, instead of being reserved exclusively for liturgical seasons of penance like lent or advent.
Peace, and Rejoice!