The whiff of a triple-shot-skinny-latte may be enough to wake you up in the morning, scientists claim.

Tests have shown that the aroma of coffee helps restore brain activity to normal levels in sleep deprived rats.

Boffins at the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, took 30 rats and kept them awake for 24 hours before exposing half to the smell of roasted coffee.

The brain activity was then monitored and those which had smelt the coffee were found to have returned to a normal non sleep deprived state.

The researchers said that the experiment provided the first ever clues to the possible reviving powers of coffee bean aroma.