From Catholic Exchange:
A new day begins. The alarm clock sounds. It is time to get up quickly from bed. The moment has arrived to offer the first sacrifice to our Lord. The body says, “No, not yet!” but the soul says, “Yes! It is time!” And the most important part, the soul, must conquer. It is the first of the many affirmations of love that, with God’s help, are to come throughout the day. It is not a matter of thinking that we are better than others, but of struggling with ourselves, aware that the sweetest victory is over ourselves, when it is offered to God.
St. Josemaría notes,
‘The heroic minute.’ It is time to get up, on the dot! Without hesitation, a supernatural thought and . . . up! The heroic minute; here you have a mortification that strengthens your will and does not weaken your body.
St. Josemaría further explains the reason for this practice:
Conquer yourself each day from the very first moment, getting up on the dot, at a set time, without granting a single minute to laziness. If, with the help of God, you conquer yourself in that moment, you’ll have accomplished a great deal for the rest of the day. It’s so discouraging to find yourself beaten in the first skirmish!