Concerned about lack of communication from workout buddy

My workout buddy and I used to text regularly to check in about our fitness goals and routines. However, they haven't responded to my messages in 5 days now. I've sent a few texts since Wednesday (it's now Sunday), and while they read my messages initially, they haven't even opened my most recent ones. I'm worried something might be wrong or that they need space, but I'm not sure. Should I keep reaching out or give them some time? I don't want to be overbearing, but I'm concerned about the sudden change in communication. Any advice on how to handle this situation would be appreciated.