Which came first: the stress or the pimples? The physical reactions to stress can cause major breakouts, which, in turn, can be even more stressful! Claudia Aguirre gives just one more reason to get that stress under control. [Directed by Alan Foreman, narrated by Claudia Aguirre].

*Yaaawwwwwn* Did just reading the word make you feel like yawning yourself? Known as contagious yawning, the reasons behind this phenomenon have been attributed to both the physiological and psychological. It's been observed in children as young as four and even in dogs! Claudia Aguirre visits the many intriguing theories that might explain cont...

The earliest recorded tattoo was found on a Peruvian mummy in 6,000 BC. That's some old ink! And considering humans lose roughly 40,000 skin cells per hour, how do these markings last? Claudia Aguirre details the different methods, machines and macrophages (you'll see) that go into making tattoos stand the test of time. [Directed by TOGETHER, na...

In the United States, it's estimated that 30 percent of adults and 66 percent of adolescents are regularly sleep-deprived. This isn't just a minor inconvenience: staying awake can cause serious bodily harm. Claudia Aguirre shows what happens to your body and brain when you skip sleep. [Directed by TED-Ed, narrated by Addison Anderson, music by C...