SOUTH BEND, IND. (WOWO) Many people may still feel tired after the annual switch to Daylight Saving Time, which moves clocks forward by one hour each spring.

Sleep researcher Ivan Vargas of the University of Notre Dame says the change disrupts the body’s natural circadian rhythm, making it harder for people to feel alert in the morning and ready for sleep at night.

The adjustment occurs because the body relies heavily on sunlight to regulate sleep cycles. When sunrise arrives later relative to the clock, the brain may not receive the usual signal that it’s time to wake up.

That shift can also delay the release of melatonin, a hormone that helps regulate sleep. Because melatonin production is triggered when daylight fades, the extended evening light can make it more difficult for people to feel tired at bedtime.

National studies have found that the Monday following the spring time change can be associated with higher risks of heart attacks, strokes, and traffic accidents.

Vargas says the best approach during the adjustment period is to maintain a consistent sleep schedule and avoid trying to compensate with naps.

He also recommends increasing exposure to bright light early in the day, which can help signal to the brain that it is time to wake up and begin daily activities.

Artificial light sources, including indoor lighting, may also help provide those cues when natural sunlight is limited.

Researchers say it typically takes one to two weeks for the body to fully adapt to the new schedule, according to WSBT-TV.