In an increasingly busy world, listening to a podcast, watching a documentary or even learning a foreign language while exercising may feel like a constructive use of time.

But a new study suggests that when the body is forced to carry out mental activity at the same time as physical exertion, the brain will win, and performance is likely to suffer.

Scientists at the University of Cambridge were curious to calculate the trade-off between physical and mental capacity when the body and brain are both forced to work hard.

They asked elite rowers from the Cambridge University Boat Club to take part in a mental recall test while exercising strenuously on a rowing machine.