In a University of Michigan study of 3617 adults, simply living in a city increased the risk of premature death (by 62 per cent) when compared with suburban or small-town life. And, of course, living in a disadvantaged neighbourhood within that city is really bad for you. A huge Columbia University study (13,000 people in four cities) revealed that white people living in the worst neighbourhoods had a 70-90 per cent higher risk of heart disease than whites living in the nicest neighbourhoods.

What's so bad about the big city? The air and water are more polluted, leading to an increase in respiratory diseases. The older housing stock is more likely to contain lead paint. One of Adler's studies found that children and adults in low-income families had six times more lead in their blood than members of affluent families. Also, there's more fear of crime, which results in chronic stress, social isolation, anxiety and depression. Crime-fearing participants in Britain's late-Eighties sequel to the first Whitehall study, Whitehall II, were nearly twice as likely to be depressed as the less-fearful civil servants.

And then there's the noise. Noise exposure has been linked to poorer long-term memory, higher stress, sleep deprivation and even heart disease. In 2005, the World Health Organisation estimated that long-term exposure to traffic noise in Europe might account for three per cent of deaths from heart disease and strokes. Noise at night can create chronic stress, even while you're sleeping, because you continue to react to sounds. This can raise your levels of stress hormones.

What's true for real estate investing is also true for your health: better to live in the worst house on a nice block than the nicest house on a bad block. You don't need a mansion to get a good night's sleep.

Click here for tip 4: