I’m lucky that my spaniel is obsessed with retrieving and would happily spend hours just retrieving,to be fair she craves for the retrieve , so I do lot retrieving and mooching abut with her while it’s cool , also do a lot of water retrieves with a heavy dummy to get her realy pushing in the water , I don’t let her get fat through the summer I keep her in decent shape, I don’t realy see point letting them get fat through summer as it’s just more work to get her back in shape