Not tonight, dear.

A report meant to highlight the health concerns prompted by rising obesity levels has found that almost three-quarters of the people it surveyed in Britain — 73 percent — said they regularly had too little energy at the end of the day for passion with their partners. More than half — 52 percent — couldn't be bothered to walk their dogs.

The survey by independent researchers at Nuffield Health, Britain's largest health charity, concluded that a national reliance on remote controls, ready meals and even Internet shopping had prompted many people to put fitness plans on the back burner.

"The decision to exercise more is important for every individual, for one's children and, it would appear, for one's dog, too," said Dr. Sarah Dauncey, medical director of Nuffield Health. "If we don't start to take control of this problem, a whole generation will become too unfit to perform even the most rudimentary of tasks."

Dauncey says the survey suggested people weren't feeling "motivated."

Britain's media came up with a simpler word: Lazy.

The startling results — including the finding that some Britons are so lazy they would watch a television program they hate rather than get up to change the channel — only angered Glasgow shoppers like Siobhan McMasters.

Scotland's largest city came in at the bottom of the poll, with 75 percent of Glasgow respondents admitting they failed to exercise at least three times a week.

"The truth is, people in the U.K. work some of the longest hours in Europe," said McMasters, a working mother. "Of course we haven't time to go to the gym or play with our kids, we're too busy being overworked."

The survey of 2,000 people across the U.K. found that one third — 36 percent — said they would not run to catch a bus.

"You start not wanting to run for the bus and end up not being able to run for the bus," Dauncey said.

A startling 64 percent of parents said they were too tired to play with their children. Nuffield Health questioned a representative sample of 2,049 adults during May. The charity did not release a margin of error.

Glasgow has one of the worst health records in the U.K. and men living in some of the most deprived parts of the city have a life expectancy of 54, compared to 67 in Iraq, according to a survey by the government run National Health Service Scotland in 2006.

Poverty, poor diet and higher rates of smoking and high alcohol intake were blamed.

Bill Laidlaw, 44, from the upscale West End area of the city, proudly patted his paunch and admitted not exercising enough.

"The only thing I'm tired of is being constantly called lazy and unhealthy by the government and doctors," he said. "Every week we're getting knocked by the government, or this survey or that. It's a free country and perhaps if they spent some money on the ground where it counts rather than these surveys, we'd all be better off."

The Nuffield Health Fitness Report said that 67 percent of people who responded in Birmingham and Southhampton failed to exercise three times a week, followed by London at 66 percent and Bristol at 64 percent.