Dr. Henry J. Michtalik of The Johns Hopkins University School of Medicine in Baltimore and colleagues surveyed 890 U.S. hospitalists and 506 responded.
Twenty-two percent of the respondents reported ordering costly and potentially unnecessary tests, procedures or consults because they didn't have time to properly assess patients assigned to them, Michtalik said.
"If a hospitalist is short on time and a patient is having chest pains, for example, the doctor may be more likely to order additional tests, prescribe aspirin and call a cardiologist -- all because there isn't adequate time to immediately and fully evaluate the patient," Michtalik, the study leader, said in a statement.
Most hospitalists reported they could safely see 15 patients in a shift if they could focus 100 percent on clinical matters.
The study, published in the journal Internal Medicine, said when the average actual workload was compared to the perceived safe workload, 40 percent of physicians exceeded their own reported safe level.
Michtalik said the hospitalists at John Hopkins Hospital typically stay below that number, while hospitalists at community hospitals often see more than 15 patients per shift.
"Hospitals need to evaluate workloads of attending physicians, create standards for safe levels of work and develop mechanisms to maintain workload at safe levels," Michtalik said.