If finding the time to head to the gym is stressing you out then this roundup [1] of studies from WebMD [2] will please you. See, the thing is, it's not always quantity that matters, but the qualitity. And in the case of exercise the old adage is true, "something is better than nothing." Here are highlights [3]:

• A study published by the American Journal of Sports Medicine in 2006 showed that short walks after dinner were more effective than long exercise sessions in reducing the amount of fat and triglyceride levels in the bloodstream after a hearty meal.
• Research published in the Journal of Epidemiology and Community Health showed that short bouts of exercise helped lower blood pressure as well as shave inches off the hips and waistline.

There's more so .

• In a study published in Preventive Medicine in 2006, researchers found that multiple workout sessions as short as 6 minutes apiece could help sedentary adults reach fitness goals similar to those achieved by working out for 30 minutes at a time.
• In a finding published in the journal Psychopharmacology, doctors found that short bursts of exercise could help reduce the craving for cigarettes and help people quit smoking.

Source [4]