What does this mean?
For sleep to be restful, it has to deepen without interruption. Short awakenings repeating through the night prevent that deepening. Even if you spend eight hours in bed, you will not wake rested if your sleep keeps rising back to the surface. Sleepiness during the day is often the result of this fragmentation rather than of how long you slept.
It matters to separate sleepiness from tiredness. When you are tired your body feels heavy, but you may not be able to drop off when you lie down. With sleepiness, your eyelids close even in unsuitable places: in a meeting, in front of the television, waiting at a traffic light. Nodding off at the wheel is the most dangerous form of this symptom, and on its own it is reason enough to be assessed.
Breathing is not the only thing that fragments sleep. Not sleeping long enough, shift work, depression, thyroid problems, anaemia and some medicines can produce the same picture. For that reason daytime sleepiness on its own does not mean there is a breathing disorder in sleep; its meaning grows stronger when it sits alongside findings such as snoring, a witnessed pause and a dry mouth in the morning.
Sleepiness that will not lift during the day is explained by looking at how the night went. The headings below bring together the causes that fragment sleep and cross over into dentistry.
Likely causes
What helps at home?
- Keep a sleep diary for a week: the times you go to bed and get up, the times you wake in the night, and daytime naps. This is the most useful document there is at an assessment.
- Do not drive, and do not operate machinery that needs your attention, for as long as you feel sleepy.
- Limit caffeine after midday; drinking more coffee to push the sleepiness down can deepen the fragmentation at night.
- Do not take sleeping tablets or stay-awake supplements on your own decision; both hide the cause of the picture and make assessment harder.
- If you have fallen asleep at the wheel or while working.
- If you fall asleep even while talking or eating.
- If the sleepiness comes with pauses in breathing at night, or with waking up gasping.
- If morning headaches and loss of concentration have become obvious alongside the sleepiness.
- If you get sudden muscle weakness when you laugh or feel excited, cannot move as you wake, or see vivid images as you fall asleep.
Frequently asked questions
- Is daytime sleepiness always caused by sleep apnoea?
- No. Not sleeping long enough, irregular working hours, depression, thyroid problems and anaemia also make you sleepy during the day. The possibility of a breathing disorder in sleep comes to the fore when snoring, witnessed pauses in breathing and a dry mouth in the morning accompany the picture.
- Why does my dentist ask whether I am sleepy during the day?
- A dentist may see findings inside your mouth that suggest a breathing problem in sleep: worn tooth surfaces, scalloping along the edges of the tongue, a narrow palate, large tonsils. If daytime sleepiness sits alongside those findings, the patient is directed to a sleep assessment. The aim is not to make a diagnosis, but to point to the right department.
- If it improves when I sleep in at the weekend, does that mean there is no problem?
- Partly recovering with a long sleep can point to accumulated sleep debt. But where the fragmentation comes from breathing, the sleepiness does not fully clear even after long sleeps, and it returns during the week. Feeling better at the weekend does not make an assessment unnecessary; you need to look at the conditions under which the symptom comes back.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.