USC doctors give advice for marathon Two doctors from Keck Medical Center at USC set the record straight on preparing for and recovering from a marathon. They talked with The Times and answered readers' questions on Monday. Some excerpts of the online chat follow. Or listen to the entire conversation here. Dr. Sharon Orrange is an internist at Keck who has run the marathon and has worked at the finish line. Dr. Seth Gamradt is director of orthopedic athletic medicine at Keck and is a triathlete. Question: Some people get in trouble by drinking too much water during the race. How do you know if that's happening to you? Gamradt: It's basically when you drink so much fluid that you drive your sodium concentration in your blood too low. 1 symptom is confusion. Orrange: When you're drinking just plain water along the course and what you are sweating out is salt and water, the problem you get is with diluting your blood sodium or your serum sodium. And when you hear about people having seizures after the marathon, or what Dr. Gamradt said, being confused, oftentimes we blame it on a low serum sodium. Your key with this is when they have the Gatorade drinks along the side, and they will, yellow and red. You need to alternate plain water with the Gatorade drinks. Q: You shouldn't run in new shoes, right? Orrange: Test your shoes out. I wouldn't even do a 10K in brand new shoes. You want shoes that you know exactly how they are going to rub. ... The things that will really start to limit you and be uncomfortable at the end are your feet, your joints, your muscles. Gamradt: It's also very important to use the Glide type gels in areas where you know you are going to have friction. Because that could end your day very quickly if you get to mile 12 and you are already blistering up. You're not going to have a very fun rest of the race. Q: Is it OK to run if you're recovering from a cold or flu? Orrange: If you have a residual upper respiratory infection, and a lot of people do right now, meaning you have this sort of persistent dry cough, a little bit of nasal congestion, there are a lot of things you can do leading up to the morning of the race. Those ... nasal sinus rinses, they'll clear you up and they're completely safe to use. ... A plain over-the-counter Claritin will help dry you out. Q: What about sore knees and feet as you run or before you run? Gamradt: I think this goes back to your training and whether your body is somewhat cut out for it. ... In general, I recommend when people are starting a marathon training program, they be within 20% of their ideal weight. A marathon training program is not a great way to say I'm going to lose a bunch of weight. You're much better mixing in some cycling or cross training if you are trying to lose some weight. Because that extra body weight by, say, mile 10 is really going to take a toll. So danger signs when you are running. I think everyone's knees hurt to a degree when they get into these high mileage zones. But the danger signs are sharp pains, pain with every step. And then afterward if you have swelling in the knee that takes ice to go down, that's really concerning. But if both knees hurt a little bit during marathon training, I think that's par for the course. Similarly, if you have foot pain that is escalating and it's getting worse with every run, that can be a symptom of a stress fracture and should get checked out. Q: People say you can run two to three times your normal distance if you are a regular runner. Is that true? Gamradt: This is probably not true. Every year we get several patients in the orthopedic clinic office that tell us that they have run the marathon and now they're having trouble with x body part. I think this is where those runners come from. ...It's people who have really tried to fit the training in under two months or something, or even shorter. They just decided to run the marathon on a whim or something. It seems like if I can run a half marathon, I can run a full marathon. The biology and physiology and biomechanics are totally different in your body after you've run 13 miles. And you go ahead and try to run that second 13 miles. So I think that is a myth. ... So if you are going to train for a marathon, give yourself the proper time frame. It's going to take you 41/2 months to really train properly. Q: What do you eat to recover from the marathon? Orrange: Anything that sounds good. ... I don't think there's any magic to it. ... I had fish tacos, a real Coke and a latte.