It might seem the ultimate relaxing indulgence, but having an afternoon nap can damage people's health, scientists have warned.

New research has found that taking a snooze in the middle of the day can raise the risk of high blood pressure by up to a fifth.

But, despite the perceived wisdom that eating cheese before sleeping gives you nightmares, another study has discovered that small amounts of Italian cheese can keep blood pressure at safer levels.
At least 16 million people in Britain have high blood pressure and, left untreated, it can lead to a heart attack, stroke and kidney disease.

Patients are given drugs to reduce the pressure, but in up to a fifth of cases these do not work.

A daytime nap is generally considered restorative and good for your health, but that conventional wisdom is now being challenged.

Researchers from the Mayo Clinic, in the US state of Minnesota, pooled data from nine previous studies with a total of 112,267 participants.

They found those sleeping for a short period in the middle of the day were between 13 and 19 percent more likely to have hypertension, which is abnormally high blood pressure.

But when the researchers looked at the the association between nighttime napping in those who work night shifts and high blood pressure, there was not the same link.

Dr Wisit Cheungpasitporn said: "More research is needed to better understand if the duration of midday sleep, or if diet, exercise, or an underlying medical condition, might be impacting risk."