This is a realistic workout program.
BUT
I strongly advise against starting on this program. If you haven't done a strict workout program before do not start with something like this. If that's your case, then do
this program, or something like it, for at least two-three months before trying the Seal program.
Back to the Seal program.
Always give yourself proper time to rest. If you ever feel overly exhuasted give yourself a day, or two, off the program; it takes eight weeks for your body to fully recover from being over-worked. I'd also be careful with that much running because it can destroy your knees. Make sure you drink plenty of water (failing to do so can result in kidney damage), and that your running technique is proper (heal - toe, leaning a bit foward). If you have an irregular running technique you can purchase insoles that are specifically designed to compensate for that irregularity. I've also found that wearing knee braces is benifitial in long distance running, and necissary if you start feeling pain. If you get shin splints, wrap the shin tightly with medical tape, or an ace bandage, from the ankle to a little over half-way up the shin. Take a day, or two, off the running as well.
When doing a program that demanding
dieting is extremely important. Make sure you eat plenty of protien, carbohydrates, and healthy fats (try avoiding trans & saturated fats) and, if you want to get technical, in a ratio of thirds (33%, 33%, 33%).
Goodluck.