Dr Mark Porter investigates the health effects of loneliness and why some researchers believe being lonely is worse for your health than obesity. Also in the programme, as proposed new UK guidelines mean as many as 5 million more people could be prescribed statins to lower their cholesterol how do you work out if you are in this new category of being at risk? Are the current calculators that work out your risk up to the job? Mark also investigates coughs. Does it really make a difference if your cough is viral or bacterial, and why eighty percent of people won't benefit from taking antibiotics for their cough. A recent study has found that long term, repeated exposure to air pollution increases the risk of heart attacks. What does this mean for people who live near busy roads, and who is most at risk? Mark Porter talks to Frank Kelly, professor of environmental health at King's College London about why the microscopic particles in air pollution cause problems for the heart and why he believes cycle routes shouldn't be on busy, main roads.