Taking It Easy After Going To The Gym? Not So Fast

NEW YORK (CBSNewYork) -- We all know that exercise is good for us. It's good for your heart, your brain, it burns calories for weight loss, and even helps prevent diabetes and cancer.

"It makes every single day more enjoyable." says Duncan Riach. "It makes every single moment more enjoyable, Makes you sleep better, it makes you work better, makes you more creative, improves your memory, improves your cognitive functioning."

So with all those benefits, you should feel pretty good about yourself. So good that you take it easy the rest of the day?

"Either consciously or unconsciously, people just did not expend as much energy during the time that they weren't exercising on the days that they exercised," says Dr. Guillem Gonzalez-Lomas of NYU Langone Health.

In other words, on the days people exercised, they weren't as active with their other normal daily activities as they were on non-workout days some folks actually spent.

According to a new study in the American Journal of Preventive Medicine, that means on those exercise days, the increase in total calories burned was only about half what was burned during the exercise.

"You may feel satisfied with having achieved the goal of going to the gym and you don't necessarily have to do anything active the rest of the day," Dr. Gonzalez-Lomas tells CBS2's Dr. Max Gomez.

Another possibility is you overdid your workout.

"We've all been there where you did something really difficult we may not want to take that flight of stairs at the office after working out at lunch," said Dr. Gonzalez-Lomas.

The take-home lesson from the study is that being very active for a part of the day and a couch potato the rest reduces the health benefits of physical activity.

"The body works best when things are spread out a bit more," said Dr. Gonzalez-Lomas.

Studies now show how harmful physical inactivity really is. In other words, sitting is the new smoking. But all sorts of physical activity can improve health, from housework to walking and gardening.