RecruitingMetabolism Evaluation Through Resting Indirect Calorimetry in Bladder Cancer (METRICS)This study is being done to learn more about energy needs and muscle function during treatment for bladder cancer. These insights can help improve future patient care. The study team found in a previous study that resting energy can be different than what estimates show. Patients with bladder cancer are known to suffer a decline in physical resilience over time. Monitoring patients to understand these changes better could help design future treatments with these vulnerabilities in mind.