Hello, I'm Dr. Kara. I have over 20 years of experience as a veterinarian and I'd like to help with your concerns about Abby's increased noise when sleeping and panting in the evening.
Snoring occurs when they have swollen tissue in the pharynx or soft palate.
If she has gained weight that could cause these tissues to become more prominent and lead to more noise.
If she is exposed to more respiratory irritants like pollens and mold spores (common this time of year) that could also cause louder snoring and panting.
A foreign body in the nose (grass awn, pieces of plant material) could also interfere with airway movement and cause inflammation.
An infected tooth root could lead to nasal inflammation and louder snoring.
Finally an upper respiratory infection (like a cold in you and I) or a nasal fungal infection could also cause these symptoms but I would expect her to sneeze as well and have a nasal discharge.
Because she is able to exercise normally I would not expect this to be related to heart disease. When she runs and plays she likely breathes through her mouth and her swollen nasal passages/pharynx aren't a problem.
If she is overweight try getting her to lose some weight.
You can also try Benadryl or a generic (diphenhydramine as the only active ingredient) at 1mg per pound orally every 8 to 12 hours (two 25mg tablets per 50 pound dog). If this is related to nasal allergies that should help.
If she isn't improving though or if she starts sneezing or pawing at her face she should see her veterinarian for an examination and possibly a nasal scope or radiographs of her nose and sinuses to look for an underlying problem.
Please let me know if you have any further questions.