WASHINGTON – Home alone, President Barack Obama turned 49 on Wednesday.

First Lady Michelle Obama has taken their youngest daughter Sasha to Spain. Their other daughter Malia is away at summer camp.

Obama hasn't shied away from talking about his birthday, noting that his hair is getting grayer and his metabolism is slowing down as another year passes. White House Press Secretary Robert Gibbs says that while there's no doubt that the presidency comes with enormous physical and mental strain, Obama "greatly enjoys" the job.

Obama is heading home to Chicago for a birthday celebration dinner Wednesday evening with friends.

He'll spend the night in his own house in the city's Hyde Park neighborhood.

Meanwhile, the President's birthday — though a year shy of the Big 50 milestone — is being used in this election year as a prime fund- raising opportunity for Democratic candidates and party organizations, through mailings, e-mails, parties and other birthday-themed outreach.

On Thursday, Obama will tour an auto plant in Chicago and attend Democratic fundraisers before returning to Washington.

Meanwhile, President Barack Obama on Tuesday announced a freeze in bonuses for federal employees who are political appointees, a symbolic gesture during a period of high unemployment.

Obama, who already froze salaries of senior White House officials upon taking office in January, 2009, made the announcement in a memo to federal agencies.

The Office of Personnel Management ''estimates a minimum of 2,900 political appointees will be affected by the freeze on discretionary awards, bonuses and similar payments,'' a senior administration official told AFP, speaking on condition of anonymity.

Political appointees, a category separate from the full-time bureaucracy, are hired at the discretion of the sitting US president. These positions are often changed when a new administration comes into office.

Obama has described the measure as another step in the effort to shrink the massive US federal deficit. (with a report from AFP)