Giovanni Cizza of the National Institutes of Health in Bethesda, Md., says many in the United States don't get enough sleep and weigh more than they should.
A study indicates people who stay up late, sleep too little and are obese also have signs that raise concern about potential heart attack risk.
Cizza analyzed data on 119 people who fit the categories of staying up late, sleeping too little and weighing more than they should.
The study, published in the journal Plos One, found those who stayed up late and lost sleep had higher resting heart rates and higher stress hormone levels.
"If you are an evening person, you tend to eat more, you tend to eat more fat than carbohydrate, and eat more often after 8 p.m," Cizza said.