It wasn’t out of disrespect.

This article is part of AP’s Be Well coverage, focusing on wellness, fitness, diet and mental health.The brain has a master clock that is set by exposure to sunlight and darkness. This circadian rhythm is a roughly 24-hour cycle that determines when we become sleepy and when we’re more alert. The patterns change with age, one reason that early-to-rise youngsters evolve into hard-to-wake teens.

Morning light resets the rhythm. By evening, levels of a hormone called melatonin begin to surge, triggering drowsiness. Too much light in the evening — that extra hour from daylight saving time — delays that surge and the cycle gets out of sync.Sleep deprivation is linked to heart disease, cognitive decline, obesity and numerous other problems. And that circadian clock affects more than sleep, also influencing things like heart rate, blood pressure, stress hormones and metabolism.Fatal car crashes temporarily jump the first few days after the spring time change, according to a study of U.S. traffic fatalities. The risk was highest in the morning, and researchers attributed it to sleep deprivation.

Then there’s the cardiac connection. The American Heart Association points to studies that suggest an uptick in heart attacks on the Monday after daylight saving time begins, and in strokes for two days afterward.Doctors already know that heart attacks, especially severe ones, are a bit more common on Mondays generally — and in the morning, when blood is more clot-prone.

Researchers don’t know why the time change would add to that Monday connection but it’s possible the abrupt circadian disruption exacerbates factors such as high blood pressure in people already at risk.

Gradually shift bedtimes about 15 or 20 minutes earlier for several nights before the time change, and rise earlier the next morning, too. Go outside for early morning sunshine that first week of daylight saving time, another way to help reset your body’s internal clock. Moving up daily routines, like dinner time or when you exercise, also may help cue your body to start adapting, sleep experts advise.Denise Jones, who enrolled in Healthy Start in February, has struggled with anxiety, depression and drug addiction, but has been sober since April.

In mid-July, baby items filled her room — a crib, a bassinet, tiny clothes hanging neatly in a closet — in anticipation of her child’s arrival. Jones, 32, flipped through a baby book, pointing to a sonogram of her son Levi, who would be born within a couple of weeks.She said she feels healthy and blessed by the help she’s gotten from Healthy Start and Madonna House, a transitional living program run by Catholic Charities of Eastern Oklahoma.

“I have professionals that are working with me and give me support. I didn’t have that with my other pregnancies,” she said. “I’m at one with my baby and I’m able to focus.”Associated Press data journalist Nicky Forster in New York contributed to this report.