For example, instead of saying “ I want to get in better shape”, or “I want to lose weight”, a specific goal would be “I want to lose 10 pounds by Easter. Or, “I want to be able to run a 5K with my friend in June”. Ten pounds is a measurable amount, so is the 5K. It’s also achievable or attainable since a safe rate of weight loss is 1-2 pounds a week. The 5K would depend on your current level of fitness, but is specific & measurable. Six months is likely enough time. Realistic means its something that’s possible or relevant to your lifestyle. Timely means you’ve set a reasonable deadline for yourself.
These programs will maximize the gains while minimizing the time invested since they can be done in 20-30 minutes. Aerobic intervals are combined with strength training sets in a circuit that creates continuous exercise. Mini circuits of 10 to 15 minutes can be done throughout the week at home to help maintain muscle strength & aerobic endurance. You do need to be in reasonably good shape to commence these!! However, they can be modified for almost anybody by a knowledgeable fitness professional. See the other caveats below.
The New York Times has even developed a web app which can be used online or on your smartphone.
Please also consult with an exercise professional, whether exercise physiologist, personal trainer or athletic trainer. A certified professional can modify a high intensity program for you and progress it safely. This can be the best investment you've ever made and will insure you won’t get injured early in the game.