Sedentary lifestyle is associated with cardiovascular and metabolic diseases. A compelling body of evidence demonstrates the amelioration and prevention of such conditions with increased levels of physical activity (PA). Despite this evidence, many public health initiatives aimed at increasing PA have failed to demonstrate clinically relevant effects on public health. It has been hypothesized that the highly controlled environments in which PA and health research is conducted limits its replicability in real-world community settings. This review aimed to evaluate the effectiveness of community fitness center-based interventions on inactivity-related diseases in adults. Data from 11 investigations highlighted 3 factors: (1) a lack of community-based PA studies, (2) a lack of clinically relevant data, and 3) further reliance on self-report and rudimentary measurements. It is concluded that the current laboratory-based evidence for PA and health is to be replicated yet in real-world settings and that rigorous and clinically relevant naturalistic research is required.