Do long nights throw off my sleep schedule?

Because it is getting dark so early and the days are shorter, some people may experience changes in their sleep schedule and quality.

Elise McGlashan, from the University of Melbourne's John Trinder Sleep Laboratory, says shorter days and longer nights mean less sunlight, which can change circadian rhythms.

The changing seasons may be changing your body's natural rhythm. (UWA)

The circadian rhythm is the internal body clock that regulates sleep.

"Those changes in sleep can also be accompanied by changes in timings and function of our internal clock and the function of our clock is mainly driven by environmental light exposure," she says.

"In summer, we know the sun might be up until it's close to someone's bedtime, and part of the reason people are sleeping a little longer is they aren't getting those light cues when they're trying to wind down.

"But during winter solstice, there is less light and more time to wind down."

When there is less light exposure, the body produces more melatonin — a hormone that makes people feel sleepy — and less serotonin, which can lower mood and energy, leading to feeling tired or sluggish.

As the sun comes up later, it may be tempting to sleep longer but oversleeping can also impact health.

Dr McGlashan recommends getting outside for some sunlight during the day and letting sunlight into your bedroom in the mornings if possible.

"Our rhythms need bright days and dark nights," she says.

"It can be hard to motivate ourselves to go outside in winter, particularly in a really chilly location, but even on those overcast days, the light outside is going to be brighter than indoor lighting.

"It's still really helpful for your body clock and sleep to get outdoor lighting every day."