This final model represents an overly stringent test because
part of the benefits of relaxation practice and exercise
may be reflected in health status. People who practice relaxation
techniques appear to be healthier than those who
do not (Table 2). By controlling for health status, the authors
hope to account for pre-existing differences between the 2
groups that could have led to selective use of relaxation
practices. Nonetheless, it is possible that these respondents
are healthier (and thus, present better physiologic profiles)
because of their relaxation practice. Thus, controlling for differences
in health status is likely to result in an underestimate
of the effect of relaxation practice.