What to say when she says she's been doing a lot of cardio classes and needs rest

When she mentions cardio classes and needing rest, she is usually explaining a gap, not closing a door. People who are training hard often go quiet, fall asleep early, and reply in bursts. That is ordinary. The thing to notice is the tone. If she sounds tired but warm, with a smile or a bit of humour, she is still engaged and wants the conversation to continue at a slower pace. If her message is flat, very short, and offers nothing back, she may be using the workload as a polite exit. You will often see both signals in the same message, so don't over-read either one. Your job is to keep the conversation easy to continue and to avoid making her manage your feelings about the delay. A short acknowledgement of her week plus one light, open thing to respond to tells you more than any amount of analysis.

Two kinds of reply tend to fit here. The first is the easy acknowledgement, where you take her point, show a little warmth, and give her something she can answer in two words if she wants to. The aim is to look after her energy. You are not trying to win the exchange. A draft is this kind when it is short, carries no pressure, and has one question at most. The second is the light tease, where you playfully notice that she has been busy and ask about the most interesting part of her week. This works when the conversation already has some back and forth and she has been funny with you before. You can tell a draft is teasing rather than needy when it makes her the subject of a fun observation rather than a complaint about the silence. Leave out apologies for texting, comments about your own training, and any suggestion that she owes you a reply. Those make a tired person feel worse, and they don't give her anything to enjoy.

Timing matters more here than the wording. If she is tired from classes, a reply sent late at night can feel like pressure, while a reply in the middle of her day feels like a nice interruption. Match her rhythm where you can. If she usually texts in the evening, reply in the evening and don't send a flood before she has had a chance to answer. Give it a day or so before following up, unless the conversation was going quickly before she went quiet. If she doesn't respond to a reply, send nothing for at least two or three days. When you do follow up, keep it as light as the first message and make it easy for her to answer without effort. If the second message gets a short reply, relax and keep things loose. If you get nothing back after two gentle attempts spread over a week or so, stop. Silence after an explanation like this is usually a clear answer.