Barack Obama's era in pictures: He aged over eight years as President - but wife Michelle looks just the same

These startling pictures show just how much the US presidency has aged Barack Obama - but not so much his wife Michelle.

The outgoing 55-year-old Commander-in-Chief is departing showing signs of the stress of the responsibilities of being the President over the last eight years.

When fresh-faced Obama gave his first address to congress back at the age of 47 in January 2009, he had slick jet-black hair and smooth skin.

Today the "silver fox" politician - and father-of-two - is showing signs of age and the stresses of his career with greying hair and baggier skin.

When you consider the age of the two candidates who vied to takeover from him - Donald Trump, 70, and Hillary Clinton, 69 - you can begin to understand why America got so embroiled in debates about their healths.

Obama's gruelling job - dealing with heavyweight internal battles over health care, gun control and climate change as well as on the world stage over issues like Bin Laden and ISIS - has involved a lot of hard work, not to mention late nights, over the last eight years.

Meanwhile, in the same time frame, Obama's wife Michelle, has blossomed.

The First Lady - who has developed a reputation for her fitness - has become something of a fashion icon and is now revered for her clothing and beauty choices.

At this point she looks like she has the energy for a third term - while her husband frankly looks like he needs a well-earned rest.

2008 - Fresh-faced on the campaign trail

2009 - First year on the top job

2010 - Another year on and he already looks older

2011 - Middle-age has kicked in

2012 - Beginning to look tired

2103 - World-weary signs emerge

2014 - The grey hair kicks in

2015 - No question, he's aged

2016 - Obama is heading for elder statesman

2017 and beyond...