Sleep is very important when it comes to staying mentally alert and healthy. This article [here] outlines some of the more practical and environmental causes of poorer sleep. The positive habits involved in helping to get a good night’s sleep are together called ‘sleep hygiene’. These articles [here and here] touch on some of these. There are disorders that are associated with sleep. For example, ‘sleep apnoea’ involves breathing being negatively affected during sleep [see here and here]. Some people are fearful of falling asleep. This is termed ‘somniphobia’ [see here]. Sometimes Somniphobics are fearful of experiencing ‘sleep paralysis’. This is a condition where you cannot move your muscles whilst falling asleep or waking up [as described here]. Do you have problems sleeping? If so, I would recommend talking to your family doctor as a first step.