Answer

In the Name of Allah, Most Gracious, Most Merciful. 

All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.

In responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:

You need to ask yourself: What happens if you were to go to bed early? Do you experience the fits even after you have had enough sleep? Or is it because of sleeping late? If the latter is the reason, then you ought to go to bed early to allow you to wake up for Fajr.

You implied that if you were to wake up late, you don’t experience such fits. So, that is an indication you would have no such difficulties if you were to condition yourself to go to bed early. Thus, you will be able to wake up for Fajr.

By doing so, Insha Allah, Allah will bless your day, and then you can call upon Him to ease your difficulties.

Prophet Muhammad (peace be upon him) prayed: O Allah, bless my community when they set out doing their work early morning.”

The companion who narrated this tradition vouched for it: He says: “I took the words of the Prophet to heart and set out doing my business from early dawn. Thanks to diligence in acting upon the advice of the Prophet (peace be upon him) my business flourished and I earned great profit.”

Almighty Allah knows best.