Two of the biggest causes for not being able to sleep at night are over-exhaustion and over-stimulation. You must clarify which of these scenarios is true for you or for your students. Are you or your students totally exhausted and beyond sleep because of working all day, or is the mind racing and the body too tense to relax? There are two different asana remedies for these conditions which make for a perfect evening practice before bed. 

For the student who is beyond tired, do a very gentle asana practice to help the mind settle down and to facilitate the transition into sleep. A suggested practice includes:  Morning Series, Hip Series, Marjarasana and restorative poses (i.e. Setu Bandha Sarvangasana with bolsters end to end at the wall, Pranayama Posture, Viparita Karani or Sarvangasana on a chair, and Supta Baddha Konasana on a bolster). Prior to Shavasana, encourage the student to do the meditation snacks, specifically centering the mind and pelvic energies, opening the heart chakra and surrounding the body with light. Focus on the light bathing the mind and soothing the nervous system.  
 
For a student who has a lot of pent up energy and is wired from being busy all day, the asana should be a little more active to help process and discharge all the pent up energy. Do poses which move the spine in all directions--inversions, forward bends, back bends and twists. A suggested asana series is the Morning Series and Hip Series for one breath each, a gentle classicval Surya Namaskar, hanging in Adho Mukha Shvanasana on a wall rope system for several breaths, Adho Mukha Svanasana to Urdhva Mukha Svanasana, back and forth 3-9 times, Shirshasana, Sarvangasana, gentle Bhujangasana, Adho Mukha Shvanasana, and finally moving into the restorative poses (same as above). This practice will help move stuck energy that prevents sleep. 
 
As a teacher, it is also important to suggest that the student remove caffeine, alcohol, tobacco, refined sugar and other nervous-system-stimulants (such as kola nut) from his or her diet. Sweet dreams!

In the next issue (in two weeks), we'll talk about some meditation practice to improve sleep.