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.

Another theory is that yawning stretches the lungs and lung tissue. Stretching and yawning may be a way to flex muscles and joints, increase heart rate, and feel more awake.

The most common medical problems that are associated with increased yawning are sleep deprivation, insomnia, sleep apnea, narcolepsy, and many medicines that cause sleepiness.

Normally, people spend most time looking at the eyes, but autistic people focus on the mouth. Although it might seem counterintuitive, the most potent stimulus for contagious yawning actually comes from a person's half-closing eyes rather than their gaping mouth, Platek says.