It can be for many reasons having to do with your body either needing more oxygen or using it to regulate your internal temperate or pressure in the ears. It also promotes wakefulness and attention, which is why we associate it with being tired or not getting enough sleep.

Excessive yawning complications include: Bleeding—You might experience bleeding around your heart. Sleep disorders—Sleep apnea or insomnia might be a hidden precursor of constant yawning. Heart attack—Heart attacks can occur with severe yawning.

Yawing clearly is associated with sleepiness and boredom. However, almost paradoxically, it is theorized that yawning is not a sign of sleepiness or boredom, but actually a reflex that your brain induces to wake you up or make you more alert.

While we no longer dismiss yawning as “vulgar”, it is seen as rude and disrespectful because it implies that the yawner is bored and is making no attempt to conceal the fact. Of course, this is not necessarily the case and sometimes overwhelming fatigue can cause a bout of yawning.