When my fitness journey started out I would always rely on motivations, my main motivation before was i want to look good when the pandemic is over. I used that everyday to jumpstart my body to move and exercise, a month passed and that motivation of mine started to diminish, zero, nada! Lets face it all of us get demotivated at some point, What ever the reason may be it just goes away.
What i have learned during this pandemic is that "Motivation can get us started, but discipline will get us to where we want to be", in the later parts of my fintess journey i realized that i had to be consistent in what im doing so that i could discipline myself to do something even without thinking about it.
i started to discipline myself first by, not thinking of my "motivation" and waking up early. I told myself that i have to do this because i want to, here are some of the things that i started.
I set all my devices to alarm time 5am.
Set my air-condition to go off 1 hour before my alarms would sound off (this is so that i would be uncomfortable and easier to wake)
Immediately stand up after my alarm has gone off and drink water and wash my face,
with these things in place i was bound to wake up. After doing this for a month my body does not need reminding of what i need to do at 5am, it automatically wakes up even if the alarm or the air-conditioning does not go off, that is how i disciplined myself to wake up early.
Same process i did with everything that i wanted to do in my fitness journey. you have to do something over and over again until your body adapts to it and it comes naturally to do it, this is my version of disciplining my body to anything i want to do.
It may be a different process for you but i suggest that if you want to create discipline in your life, first you have to learn to love what you want to do, and your reasons are right, do if not even though you try hard enough nothing will bear fruit of it.