There is growing concern that the increased exposure to artificial sources of blue light from lighting and digital screens, is having an effect on our health.
Auckland University's Associate Professor Guy Warman told Kate Hawkesby blue light is very effective in shifting our body clocks.
He said blue light in the morning will shift us to an earlier time zone.
"What's happening these days, is that people are exposing themselves to more and more blue light late into the night and that has the opposite effect, it delays our clocks to a later time zone and it effectively gives us jet lag."
People are exposing themselves to blue light through LED and artificial lighting, he said.
"With electronic devices like our phones and iPads and computer screens, we are exposing ourselves to more and ore blue light which is far more effective at switching our biological clocks."
LISTEN ABOVE AS GUY WARMAN SPEAKS WITH KATE HAWKESBY