As more and more studies establish the importance of sleep, and specially of continuous sleep, I am wondering how does praying fajr impact sleep. I recently started praying fajr, and I am finding that due to split sleep, I am not as refreshed as I used to be when I used to sleep continuously. I live in North America where time duration between Isha and Fajr is only 3.5 hours during summer months. Therefore, sleeping early is not an option. I dont want to miss fajr either. If someone has found the right balance of sleep and prayer, then I would love to know. Thanks!!
In light of the fact that prayer has to be offered at its time and Fajr cannot be combined with any other prayer, your only option is either to (a) stay awake for that 3.5 hours [maybe do Tahajjud or read Qur'an] and then sleep after Fajr continuously or (b) continue sleeping as you have been, waking up for Fajr in between. Perhaps being "less refreshed" is worth Paradise.
If you want to know the practice of early Muslims, Allah (ﷻ) said, إن ربك يعلم أنك تقوم أدنى من ثلثي الليل ونصفه وثلثه وطائفة من الذين معك (Indeed, your Lord knows, [O Muhammad], that you stand [in prayer] almost two thirds of the night or half of it or a third of it, and [so do] a group of those with you" - Qur'an 73:20. -- They would be up portions of the night praying and then sleep... and then they would take a humble mid-afternoon nap.
It will actually greatly benefit you if, after deciding to keep waking up for Fajr, you take a mid-afternoon nap as well. That extra rest will again freshen you up for the remainder of the day.