I have only run one marathon so far but a few miles after the halfway point I was unable to keep the same pace i held for that long. Is there anything I should do the days before, the morning before, and during the marathon to prevent that from happening?
Most issues are pacing issues! So make sure you run the correct pace early in the race. I like to carb load 3 days out I am 150 lbs so my wife will give me around 650 grams of carbs a day for the 3 days before a race. Fueling during the race for me I take a gel every 40-50 mins with water and take a slip of sport drink the aid station between my gels! Biggest issue is to pace correctly based on your fitness level! If you go out to fast it will be a long last 10K! Good luck
Fat old man PRs:
Not sure what your training plan was but you might want to try something different if the one you followed left you feeling tired at the half way point. Active has lots of great training plans for various fitness and distance goals. I agree with the previous posts that you probably need to adjust your pace. I'd suggest a Garmin or other sports watch to help with that. I'm a horrible judge of how fast I'm going and my Garmin has been a huge help with keeping a steady pace for long distances.
In addition to what has been said before, particularly about starting off slowly, your training program should have one or more long runs of 18-22 miles 1-2 months before your event. Gel supplementation can help. But, most frequently, runners run the first 12 miles too fast.
You will get a long way with a proper nutrition startegy for the race. I wrote this post on my blog a while ago.
Hope it is helpfull.
To oxygenate your muscles thoroguhly, I suggest speedwork once a week during marathon training and a monthly 5K race, as well. I take cordyceps, too, to make the oxygen in my blood more available.
One other thing: Carry lots of water on your long runs to make the run harder.
Eat alkalizing foods.
Probably the one best word of advice is what shipo said: Get lots of miles in.
Wading through 30-40 miles a week can require regular massage, stretching,
epsom salt baths and getting down and dirty with a hard foam roller.