Many people stay up late on weekends and then sleep in to "catch up" or get enough sleep. I used to do this as well until I learnt that keeping the same sleep/wake cycle worked much better for me when it came to having more energy and having a better mood. My focus is a lot better by doing this and I am not fatigued at the start of each week. I have much more consistent energy and feel my training drive is much better.
"Every hour is also associated with an 11 percent increase in the possibility of heart disease. These effects are independent of sleep duration and symptoms of insomnia, which are related to both social jet lag (staying up late on weekend and sleeping in) and health." Brackets added are mine.
So a simple way to prevent heart disease, and other disease for that matter, increase your mood, energy, and training drive, is to actually keep the same sleep/wake cycle. If you go to bed at 9.30 pm and wake up at 5.30 am during the week, then keep that same cycle on weekends. The benefits are worth it and you will get so much done on a weekend before most people have even woken up.