<human>: Summarize the given text in a few sentences.

We've had my girl since early June. She was given to us from family who could not keep her anymore. She is an excellent dog, but old and about 20-30 pounds overweight. 

Over the last few days I've noticed her twitching a lot, all the time. When we first got her, it only happened when she was sleeping; currently, we see it as she sleeps, but not as if she is dreaming. Also, when she wakes up, it doesn't seem to stop, and sometimes (over the last 2-3 days) I've seen it more while completely awake. Twice now, yesterday and earlier today, it was so bad she was upset by it and actually placed her paws on her nose to make it stop (really cute, but also worrisome.)

The other thing that is bothering me is she is way more playful. I'm sure I am being paranoid, but it seems as if she is desperate to prove she can still play. She will be apparently tired, and still beg to go outside and play ball. We can play for 30 minutes, where she is running back and forth across our yard the entire time (which the vet has advised against, saying with her weight and joint problems, 10 minutes of moderate exercise at a time is pushing it), and when we come in, she is still begging to go out, but exhausted. We play 2-4 times a day, depending on her mood, the heat (it's been in the 95-105 range), and what we have going on.
<bot>: My dog is twitching all throughout the day, is playing more often, almost as if she is desperate to play even though she is getting significantly more exercise than the vet recommended. Advice?