"In a nationwide American time-use study, we're clearly seeing that, at the time of daylight saving time extension in the spring, television watching is substantially reduced, and outdoor behaviors like jogging, walking, or going to the park are substantially increased," [environmental economist Hendrik Wolff] said. "That's remarkable, because of course the total amount of daylight in a given day is the same."
But others warn of ill effects. Till Roenneberg, a chronobiologist at Ludwig-Maximilians University in Munich, Germany, said his studies show that our circadian body clocks—set by light and darkness—never adjust to gaining an "extra" hour of sunlight at the end of the day during daylight saving time. "The consequence of that is that the majority of the population has drastically decreased productivity, decreased quality of life, increasing susceptibility to illness, and is just plain tired," Roenneberg said.
For more, nerd out with the physics of Daylight-Savings.