Sleep plays a major role in preparing the body for an alert and productive tomorrow. But s

leep is not a period of inactivity. The sleeping brain is highly active at various times during the night, performing numerous "house keeping tasks". These keep us alive and aid our ability to think and remember. Sleep also energizes the body and brain. Most people spend one-third of their lives sleeping and this will affect the other two-thirds in terms of alertness, energy, moods, body weight, perception, memory, thinking, reaction time, productivity and performance.

To limit sleep means our health and daytime potential are significantly reduced. So, good sleep strategies are essential in order to feel energized day after day. There is no strategy which works for everyone, so each person needs to experiment. One important thing is that you shouldn't worry too much if you go a few nights without a lot of sleep. It won't ruin your life. On any given night, one in four people can't sleep properly and everyone suffers from a lack of sleep at some time.

How does one minimize this problem？ It is really quite simple. The first thing you must do is to reduce stress as much as possible. Stress is part of everyday life and, while we can never be entirely without stress, it can be managed. This means taking control of your life and focusing on what is important. One sleeping strategy is to sit in a comfortable position, close your eyes and relax all your muscles, breathing easily through your nose. Continue this for ten to twenty minutes. This should help you reduce stress and sleep better. Or, you can try getting plenty of exercise, because a tired body is likely to sleep better.

According to the article, sleep is important because______.

A．it is a period of complete inactivity for the brain

B．it helps us understand what we have already achieved

C．it makes us more effective when we are awake

D．it helps us to lose weight