The Gallup Healthways Well-Being Index survey, conducted by telephone May 1-31, of 30,252 U.S. adults, found 55.2 percent said they exercised for at least 30 minutes three or more days per week in May -- up from 53.9 percent in April, and the highest month since the survey on exercise began in 2008.
Exercise generally changes seasonally -- down in fall and winter and more in the spring and summer. However, from October 2008 -- the start of the U.S. economic crisis -- through December 2009, monthly exercise levels were lower than Gallup recorded during the same months before or after that period.
However, U.S. exercise habits rebounded in early 2010 and have been generally at four-year highs in 2012, Gallup officials said.
U.S. adults exercise rates have been up since last December -- a trend that coincided with the unusually warm weather since winter. This winter was the fourth-warmest on record, Gallup said.
The survey has a margin of 0.7 percentage points.