Hey biggers, Swimming is amazing, i swam 4 times a week for 3 yrs and loved it always wished i hadn't stopped. To start with i aimed for 40 lengths (25m pool so 1k total distance) altering stroke every two lengths. Got down to 40 lengths in 20 mins then moved up to 64 lengths (1 mile) and just did it at a speed i felt comfortable. The only problem is getting started, once u get so doing 20 lenghts and not feeling like u will die all will be good. Massive warning, you will gain weight but lose fat. I put on nearly two stone (not all muscle as i found a love for burgers etc) but u will feel really good. Regards