Compare Running and Swimming for Someone Starting Fitness From Zero

Both seem like good ideas and both have enthusiastic advocates who will tell you the other one is wrong. Joint impact, learning curve, and access are the practical questions that actually separate them for a beginner. This compares both on the things that matter and gives a direct recommendation.

I want to get fit for the first time and I am deciding between taking up running and taking up swimming.

Compare the two activities across:
1. Joint impact: which is easier on a body that has not exercised recently
2. Learning curve: how quickly a complete beginner can do something that feels like exercise
3. Practical requirements: kit, access, and cost to get started
4. Social options: how easy it is to do with others or find a group

End with a direct recommendation for a beginner starting from zero and one sentence on when the other option would be the better choice instead.

Keep the response under 200 words.