Rugby requires excellent spatial awareness and hand-eye coordination for catching the ball on the run, plus speed of thought for making split-second tactical decisions.
Football also requires these skills, but your brain works that bit harder because it's more challenging to receive and control a ball with your feet than with your hands.
Rugby players need the raw strength to body-tackle a person and bring them to the ground, or lift a fellow player in a line-out. In a scrum, a team can be resisting up to 800kg of weight with their bodies.
Football requires a strong core for swift changes of direction and powerful leg muscles for jumping and explosive sprinting, but you won't build the full-body strength you get from rugby.
The aggressive contact nature of rugby means your risk of injury from tackles and scrums is relatively high. This can range from cuts and bruises up to more serious head and neck injuries.
Football injuries are more likely to occur from overuse, rather than from contact. Achilles and patellar tendon injuries are common, as well as anterior cruciate ligament injuries in the knee.
It really depends on how you like to get your kicks, but if it's 80 minutes of mud, sweat and being leapt on by several people at the same time, then rugby is your game.
Football is a little more civilised when it comes to tackling, but 90 minutes of intense exercise and the thrill of scoring a goal give an unbeatable natural high.
An 11st person burns 700 calories an hour playing rugby, and it often requires players to sprint immediately after hard, physical contact such as making or receiving a tackle.
Football is a longer game and has fewer breaks, but burns fewer calories (630 an hour for an 11st person). Footballers also need the endurance, agility and flexibility of rugby players, so it's a draw.