Grapes can help lower blood pressure and improve heart function, new research has revealed.

Scientists examined the effects of red, green and purple grapes on rats that develop high blood pressure when fed a salty diet.

After 18 weeks, the rats that ate the grape-enriched diet had lower blood pressure, better heart function, reduced inflammation throughout their bodies, and fewer signs of heart muscle damage than rats that ate a salty diet but no grapes.

Chicago researchers have discovered that a lack of sleep means you’re much more likely to develop high blood pressure, particularly if you’re middle aged.

According to the study, missing one hour of sleep (on average) over five years will raise your risk of high blood pressure by 37%.

"People who didn't sleep as much were at greater risk of developing hypertension over five years," said University of Chicago researcher Kristen Knutson in the Archives of Internal Medicine.