But how about all the other stuff that isn't necessarily in a training guide? Is that big breakfast going to cause trouble at Mile 8? What if you hit the wall when you're 10 miles in, with no transportation other than your legs? And let's not even talk about chafing. Actually, let's.
How to avoid raw thighs and blistered toes
Chafing and blisters happen because of friction. Take two objects rubbing together (your thighs, or your toe and sock), add heat, and you will get friction. And sweat just makes it worse. How to avoid it? Choose smooth, seamless fabrics that wick away moisture, and use anti-chafing products such as Vaseline or Body Glide.
Carl Ford, a coach for DC Road Runners and a finisher of 24 marathons and two ultramarathons, says smear anything that "sticks out."
Nipples? Yes. Inner thighs? Yes. But also more unexpected areas, such as the stomach. Whether you are overweight (meaning the belly sticks out) or you have a defined six pack (meaning parts of your belly stick out more than others), get ready to smear.
There are also nipple protectors on the market, but small circular bandages might do the trick.
Lee Firestone, a Washington podiatrist, running coach and longtime runner, recommends wearing tight acrylic socks and a tried-and-true running shoe, and keeping your toenails short. (He sees plenty of blisters and lost toenails in the medical tent during races.)
If it's particularly hot, lace your shoes higher to prevent your foot from moving around in your shoe, which can cause too much skin friction.
"We often get blisters running downhill because the foot is moving forward in the shoe," Firestone says.
Food: Energy without gastric distress
"Part of your training has to be figuring out when and what to eat and drink depending on the distance you're running," Ford says.
Which means it's really a matter of trial and error and very individual. See what works in your body, says Debi Bernardes, a triathlon coach and owner of UCanDoIt Coaching. Some athletes will eat two to four hours before a training run or race, while others will just have water. "I can't do any solid food for up to two hours before a race," Firestone says.
For longer training runs and races, usually 10 miles or more, many runners require some food mid-run. Sports gels are popular, although some folks prefer "real" food. Just like with hydration, small bites rule.
Surprises can include cramping and diarrhea. The likely reasons for so many runners having gastric distress, called "runner's diarrhea," include jostling of the organs, nerves and anxiety, and a lack of blood flow to the intestines.
Although runner's diarrhea isn't fully understood and can't always be avoided, coaches recommend hydrating appropriately (early and often), avoiding caffeine and alcohol, and reducing anxiety as much as possible. But it all depends on the individual. Some people can drink tubs of coffee, while that would send others on repeated nature breaks. Some can tolerate high-fat foods, while others can't.
Ford even completed a race where he consumed 11 doughnuts midway and another where he enjoyed a chili half-smoke. "You can get used to running with food in you. But it's not at your normal race pace," he says. "It's a fun event, not really a race."
Hot days: Slow down
Whether you're training or racing, a hot day is likely to mean a slower pace. Or, as Ford experienced in a marathon a few years ago, you might hit a wall, getting lead legs with many miles to go.
"I had a great first 19 miles, and the last part was a death march," he says.
He was participating in the Rock 'n' Roll Marathon in New Orleans in late February, after having trained in the D.C. winter, and it was 78 degrees and humid.
"I didn't fully account for the humidity, and my pace was too fast in the beginning," Ford says. His goal was a 3:45 finish, and he was on target for that until Mile 19. The last few miles were significantly slower. He finished in 4:17.
Bernardes knows the scenario well and says she starts "stupid slow" on hot and humid days.
"No matter what, unless you are a regular racer, no one is going to run a [personal record] on a hot day," Bernardes says. If the temperature is over 80, with humidity of 80 percent or more, she recommends slowing down by 20 seconds per mile.
And make sure you're dressed properly for the weather. Many runners subscribe to the rule of wearing clothes for weather 20 degrees above the actual temperature. On race days, many use throwaway layers they can discard once their body heat is up to snuff.
Hydration: Early and often
Another important consideration as winter turns into summer is to hydrate properly. For those who train early in the day, Bernardes recommends 12 ounces of water with a pinch of sea salt (unless you have issues with salt) when you wake up, to replenish the salts you lose breathing throughout the night.
"Too many athletes just drink a ton of water not realizing that they are actually flushing their store of electrolytes (remember, electrolytes are minerals that help to conduct electricity, which your muscles need to fire)," Bernardes wrote in an email.
If your run is less than six miles, you probably don't need electrolytes. But if it's hot, you're running longer than six miles, and you sweat a lot, a sports drink might serve you well.
The main thing about hydration is to never wait until you are actually thirsty. Then it's too late.
The amount of hydration needed is dependent on several things, including a runner's sweat rate. To find out how much you need to hydrate, Firestone recommends checking the color of your urine after training runs and even weighing yourself to see how much weight in fluids you need to replenish.
Also, if you are racing, make sure your stomach tolerates the race-featured drink - whether Gatorade, Powerade or some other sports drink - before race day. You can usually find out what brand is being used on the race website. Buy some in advance and try it on a training run.
Race day: The three P's
All coaches agree on the importance of arriving early, up to an hour before the race starts, so you can prepare adequately and calmly.
Bernardes has a name for the three keys to being decently prepared.
"It's the three P's: parking, pooping and pacing."
Boston is a fitness trainer and freelance writer. She can be found at gabriellaboston.com.