Most health experts agree that you need a minimum of 120 minutes of physical activity per week. However, do you ever wonder how they arrive at that number? For example, why can’t you get by with 100 minutes or less? Why does it have to be two whole hours of time?According to the numerous studies that have been conducted to determine the appropriate amount of exercise necessary for fitness, 120 minute is the minimum for three specific reasons:This is the amount of physical activity necessary to reach maximum flexibility. This is important when engaging in everyday activities such as bending over to tie your shoes or when reaching down to pick up your child. The easier you move, the easier it is to live life to the fullest.120 minutes is also the minimal amount necessary to start to obtain some serious health benefits. In fact, if you are willing to do more than the 120 minutes each week, for each 10 minutes you add, you gain more and more advantages when it comes to looking good and feeling great.Finally, the 120 minutes is the threshold where the benefits of working out outweigh the risks. Your rate of possible injuries declines after this length of time, as does the chance that you may suffer from a heart attack or other potentially fatal condition.If possible, you want the two total hours of time to include vigorous activities that really get your heart rate going. One way to tell if you are in the zone is when you can only say one or two words without having to take a breath. Some activities to consider are aerobics, running, jumping rope, and tennis.It only takes you 30 minutes a day four days a week to meet this minimum requirement. So, what are you going to do to fill up this time and enjoy maximum health?