Many Americans don't get enough sleep, and researchers say that could increase the risk for health problems, including weight gain and cancer.
"Lack of sleep can hinder the ability to fight cancer by altering the actions of cortisol and melatonin, two hormones which could influence the behavior of cancer cells," Dr. Larry Altshuler explains.
"Our brain actually makes more ghrelin. ... This is the 'go' hormone. It drives us to eat. Leptin, which is the satiety hormone that tells us, 'Whoa, I've had enough; I'm not that hungry' — there's less of it," Dr. Jennifer Ashton said.
In one study ABC looked at, participants restricted their calorie intakes and slept for either five or eight hours.
The group that slept only five hours saw their bodies eat away at muscle mass, while the group that got a full eight hours saw their bodies consume fat instead.
Lack of sleep is linked to more and more health problems, but year after year, Americans tend to prioritize other things over the recommended eight hours.
The Centers for Disease Control and Prevention even called insufficient sleep a "public health problem."
According to the National Sleep Foundation, adults 18 to 64 years old should get seven to nine hours of sleep a night.