Can the 30 minutes of cardio exercise be spread out throughout the day?

If you're trying to lose weight, yes: the important thing is to get the work in.

No, it would not be as effective as all you would be doing is warm up and stop so you could never stay in your Aerobic THR Zone (Target Heart Rate) for cardiovascular improvement. The Aerobic Zone is 70% to 75% or the MHR (Maximum Heart Rate). The MHR is 220 minus your age for 80% of people (10% have a lower MHR and 10% have a higher one). BUT you would still burn calories, like 40 calories for 5 minutes, and 240 calories for 30 minutes, so this would still help you maintain your weight if you eat more that your BMR (Basal Metabolic Rate). In a way, you could not really call it “cardio”, since you would never stay in your Aerobic THR zone for cardiovascular health. The recommended 30 minutes is really a 5 minutes warm up, followed by 20 minutes in your Aerobic THR zone and then a 5 minutes cool down. So it’s more like you need a minimum of 20 minutes in your Aerobic THR zone for cardiovascular health. The government decided at one point to tell people that 10 minutes 3 times a day would be as effective as 30 minutes once a day, so people who are so out of shape that they cannot even stay in the Aerobic Zone might start exercising, without the fear of having to sweat all over the place. Also, if you want to squeeze in some physical activity when you’re working, you don’t want to sweat in your working clothes. 10 minutes would be warming up for 5 minutes and then cooling down for 5 minutes. Hopefully, if you do only 5 minutes, you should warm up for 2 and a half minute and then cool down for 2 and a half minute…otherwise you get into your THR zone and you’re left hanging up there. Without a cool down, you can get dizzy or nauseous.