The Gallup-Healthways Well-Being Index also found those who were not in the workforce at all report the worst health.
Employed U.S. adults have a score of 81.4 on the Gallup-Healthways Physical Health Index, compared with 76.1 among those who are employed part time but seeking full-time work, 75.2 for those who are unemployed and 68.8 for those not in the workforce.
Employed Americans in every age group report better physical health than those who are underemployed or those who are not in the workforce, particularly among those ages 30 to 64.
Those not in the workforce -- not employed and not actively seeking employment -- have the worst physical health overall, but this is partly due to most of these individuals being of retirement age.
Even among seniors, those who are working report better health than their counterparts who are not, the survey said.
This pattern holds among those ages 30-44 as well as those ages 45-64, and this might be, in part, due to those who have lost or cannot hold work because of poor health and have now stopped seeking employment, Gallup officials said.
The Physical Health Index, one of six sub-components of the Gallup-Healthways Well-Being Index, includes 18 items that measure sick days in the past month, disease burden, health problems that get in the way of normal activities, obesity, feeling well-rested, daily energy, daily colds, daily flu and daily headaches.
The telephone survey conducted Jan. 2 to May 21 of 474,195 U.S. adults has a margin of error of 2 percentage points.