Should I worry about my senior dog losing muscle?

Sarcopenia, the gradual, age-related loss of muscle mass, happens to some degree in nearly all aging dogs, driven by natural changes in metabolism and typically reduced activity levels compared to younger, more energetic years of life. This is a normal biological process rather than a disease, and mild loss over the course of several years is generally not something to feel alarmed about.

Adequate dietary protein, generally similar to or higher than what a healthy adult dog needs, helps support remaining muscle mass overall through the senior years of life. This is part of why many current senior food formulas maintain rather than reduce protein content compared with adult formulas. Regular, appropriate exercise, even gentle activity like short walks, also provides an ongoing stimulus that helps preserve muscle far better than complete inactivity would.

Rapid muscle loss occurring over just weeks rather than years, muscle loss concentrated heavily in one area such as the hindquarters, or muscle loss accompanied by genuine weakness or difficulty rising all deserve a proper vet examination, since these patterns can sometimes point toward an underlying condition beyond simple age-related change alone. Running your hands over your dog's body regularly helps you notice these changes by feel well before they become obvious just by looking.