This is an adjustment that should be done if possible but could be "easier said than done" for many. If you are working a normal "9 to 5" job, by the time you get home, de-stress, have dinner and spend time with your family, it can already be 8 at night. Vigorous late-night exercises can make it hard for you to fall asleep and can lead to chronic post-workout insomnia if you are not careful.
Researchers recommend that a person will find the greatest benefit from exercising on their sleep patterns if they are able to complete their exercises 3 hours prior to their bedtime. 