As Chris bulks up for ‘Thor: Love and Thunder’ he needs to build a body that looks right for an immortal god. But, he also wants the kind of muscles that are scientifically proven to help him stay strong and healthy as he grows older in real life. Teaming up with extreme sports guru Ross Edgley, he trains for a grueling 100-foot rope climb challenge, changing him from an ornament into an instrument.

Medical journalist Michael Mosley teams up with scientists whose latest research is turning common knowledge about fitness on its head. They reveal why 10,000 steps is just a marketing ploy and that two minutes of exercise is all a person needs each week. They discover how to get people to stick to their fitness plans and what exercise can actually make everyone more intelligent. Whether it is for couch potatoes who hate the thought of exercise, someone too busy to consider the gym, or even for fitness fanatics who are desperate to do more - science can help everyone exercise better.
By the end of January many people struggle to keep up their resolutions to be more active. The result is that people wastes millions on unused gym memberships. But new science has the answers.