Aerobic physical fitness is a dynamic process. Rat studies show that cardiac benefits gained over three or four months are lost within a month once training stops. The size of heart muscle cells, contractile capacity, and arterial relaxation are directly related to intensive exercise programmes, suggesting that the changes are brought about by cellular mechanisms (Circulation 2004;109: 2897-904).

People often say they don't want flu jabs because they think their last jab caused a flutype illness. But it doesn't really stack up. A randomised controlled trial of acute respiratory illness in patients with chronic obstructive pulmonary disease found that influenza vaccination is highly effective at preventing influenza-related acute respiratory illness, regardless of the severity of the underlying lung disease, comorbidity, age, or smoking status. Vaccination's overall impact on acute respiratory illnesses depends, of course, on what proportion of circulating infections are attributable to influenza (Chest 2004;125: 2011-20).

Marriage doesn't suit everyone. Most studies have focused on newlyweds, but an examination of depression and age among married people found that of the three cohorts followed—young, middle aged, and older adults—older people scored significantly higher on marital satisfaction than the others. Untangling things further, this study found that marital satisfaction was more strongly related to depression for older people than for younger …