If you’ve decided to train for running a marathon, this will be a long journey, but well worth it. The work will be challenging both physically and mentally, more than you may have ever experienced before. Some days you will be at the top of the world, and other days you’ll want to quit.

A plan is the most important thing in training, stresses Active.com:Running. As you age, the planning is even more important. You’ll need to identify the different training types you do on different days, and how they all relate to the big race. Your stress increases should be gradual in intensity and volume.

On your easy days, your body needs to recover from harder days. Don’t try to use your relaxation days to further your fitness. Your body needs to rejuvenate. If you don’t allow your muscles to repair themselves, your upcoming workouts may be sub-par.

For beginners and first time marathon or half-marathon runners, it is important to train yourself to a positive level before you attempt your first race. If you often run three or four times each week, you may be ready to begin training for marathons or half-marathons.

One positive plan includes 18-36 miles of running a week, with longer runs starting at eight miles and peaking at 20 miles. You will also be doing some speed work. Following a well-established plan will help you to gain confidence as you track your fitness level.

Cross training can be beneficial to keep you from becoming burned out as you train, according to Runners World. You can log some faster miles for help in building stamina and keeping you strong in the later stages of marathons.