Damage from chronic lack of sleep is not repaired in one night though that can make a big difference, the restoration really comes with a change in lifestyle that embraces not just routine evening winding down and getting to sleep before midnight but also a welcoming of daily highs and lows, a comfortable enjoyment of the rhythms of life. The figure below demonstrates the changing of yang into yin, and yin into yang, day into night and night into day. If we wait until midnight or later to get to sleep yang is already rising and sleep will not be as restorative.
To get a good nights sleep we train ourselves to let go of the days events. Besides training in meditation to watch thoughts come and go we can shake off the physical accumulation of tension with an evening walk, a shower or a wash both literally and energetically removes the debris from the day.
Closing out the day with compassion meditation is a great way to release the stories generated by mind, to retain the beneficial impacts and dissolve the harmful. It can be accomplished in several ways but it is always important to start with yourself, to direct compassion toward yourself first, this may seem counter intuitive or you may feel resistance to this, feeling responsibility and blame or shame but this is why it is so important, to be effective you have to start right here in your self. To arouse compassion think back to an event, a situation a being that you felt compassion for or from and feel that sensation, hold it in your heart and then direct it to your target, visualize giving it, handing it over like a gift or a life raft, let your intuition be your guide. You don't have to work hard at this, make it easy, make it natural, enjoy it. More Information is available in Sensei's book "the Missing Peace."
Training in meditation helps us let go of the stories that keep us from resting. We train to let stories - thoughts, come and go without getting stuck on them. Discernment gained in meditation clarifies what is true and what is false and what is neither. This is the insight we achieve through stillness, the practice of the Dhamma.
Beyond meditation we must consider the body and how it works. Sleep is essential to good health and good sleep is a product of good health. Diet plays a big part in both. Taking time to eat well is a counter part to taking time to prepare to sleep well. At all times we should avoid eating in any way that causes discomfort, indigestion, bloating or burning, but especially in the hours before sleep.
Beside food we take in other substances and ideas and information. These things have to be evaluated for benefit before consuming, is it worth the result? If not we can choose to refrain, this is the practice to repeat in daily life over and over again. Regular exercise that is balanced and satisfying but not overdone keeps the pumps that run the body in good working order. We all know this, it is a matter of doing it.
If sloth and torpor interfere with your meditation perhaps you need sleep. Perhaps you need to adjust your diet or your exercise. Traditional Oriental Medicine is able to define and correct the root of imbalances that interfere either with meditation or sleep. A licensed acupuncturist can help.