Spend long enough on fitness social media and you’ll see the same tip. Finish every weight training session with about 15 minutes of cardio to boost your “gains”. But does it actually work? Probably not as much as you’d think.

Doing cardio and weight training in the same exercise programme is known as “concurrent training”. This includes doing cardio in the same session as your weights, or on separate days.

For years, people thought concurrent training held back strength and muscle gains. This worry goes back to 1980 when a ten-week study found that people who did both on the same days, within two hours of each other, built less strength than those who only lifted.

This became known as the “interference effect”: the idea that cardio gets in the way of building muscle and strength. And there’s some logic to keeping cardio short. A 2012 review found that the longer and more often people did cardio alongside their lifting, the more it ate into their strength, muscle and power gains. That puts a 15-minute bout at the low-risk end.

But research has come a long way since 1980, and now shows the interference effect may not be as significant as once thought.

A major 2022 review pooled 43 studies involving 1,090 people. It compared people who did cardio alongside a weights programme against people who only did the weights programme.

Adding cardio made no real difference to how much muscle........

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