Just 45 minutes of exercise a week boosts the brain power of people in their fifties and over, major new research has revealed.

A review of dozens of previous studies found that even one session of moderate aerobic and resistance activity is enough to enhance people’s alertness, decision-making and memory.

Scientists have long believed that exercising slows down the cognitive decline that occurs naturally as people move from middle to old age, however the new analysis is the first of its kind to show that brain power actually improves from staying fit.