Preparing for marathons and half-marathons

February 16, 2019 Ronan Cahill, MD

With the start of the new year, it’s time for new resolutions and new goals. For many, myself included, this means choosing a half-marathon and/or marathon to complete. For some, preparing for a long event like this is old hat, but for the rest of us it comes with a certain amount of trepidation and questions. There is a lot of information out there on preparing for these events, but I will attempt to address 3 big categories in this post. Fortunately, running is a relatively straightforward activity, and as long as you start planning well in advance the road should be nice and smooth.


In my mind, the primary question is “How many miles should I be running and how often?” The general consensus is that you should plan for about 3-4 months of preparation for a half-marathon and 4-6 months for a full marathon. Obviously, this number will change rather dramatically depending on your current mileage. If you are currently a sporadic runner with an average of 1-2 runs a week between 3 and 5 miles, I would urge you to err on the longer preparation timeline. However, if you currently run between 15-20 miles a week, then you are in a great position to safely ramp up your mileage over 2-3 months for a half and 4 months for a full.

However, if you haven’t yet been running much this year, I recommend picking a starting distance that you know you can do and building from there. For example, if you know you can run 1-2 miles, start with that distance 3 times a week and slowly build.

Regardless of your starting distance, the golden rule of sports medicine is the same: Never increase your mileage, intensity or duration by more than 10% per week! This has been shown to be the sweet spot for bony and muscular health. Less than this and it will take forever to build to the longer distances. More than this and you set yourself up for overuse injuries: stress fracture, shin splints, achilles tendinitis, IT band syndrome, etc.

In the beginning, a 10% rate of increase is a painfully slow progression,but that’s ok! If you need more of a work-out this is a great time to do low-impact cardio activity (cycling, elliptical) or to cross train by lifting weights. Just because you are going to run a marathon doesn’t mean you can’t do other activities!

One last thing on running: Don’t be afraid to mix in some interval work. This does not have to be on a track though. An easy way to do this is to break a run into ½ mile or 1-mile increments and run one segment at a harder pace and one at an easier pace. This variation helps mix up your runs, but also prepares you for moments of more intense running during the actual event. 


Cushion. Minimalist. Low-drop. No-drop, Control. Neutral. The list of shoe attributes could go on and on. So which shoe is right for you?

It turns out that you are the only one who can answer that question. Ultimately, the best shoe for you is the one that feels good. I personally try on several shoes every time I buy a new pair because the models change from year to year and new models do not necessarily fit in the same way as the old models. And make sure to run in them - either on the store treadmill, on the sidewalk or if the store offers a 30-60 day run guarantee bring them home and try them out for real. If they don’t feel right don’t feel bad about bringing them back, they want you to like the shoe as much you want to like your shoe!

The odds are that when you buy a shoe, the store employee will suggest insoles. Should you buy them? This is a little harder to answer and really depends on the shape of your foot, the amount of running you do and your overall fitness. The arch of the foot is like a spring, and some people have a perfectly tuned spring and some people need a little more support. If you have a flat foot you may benefit from a mild to moderate arch support to prevent stressing the inside of the leg and ankle. However, if you have a high arch you may want to play around with different shoe and insole combinations to find a shoe that just feels better. But most importantly, if you do change your arch support, make sure it is early in your training as changing the arch support changes which muscles work harder while running and could set you up for injury.

Eating and Drinking

One question many people have about marathons and half-marathons is how much they need to be eating and drinking. There are a lot of opinions on this, and there have been many, many scientific papers written on optimal fueling schedules. However, there are a few general guidelines that I think apply to most people. 

In the days leading up to your event, make sure to be drinking plenty of water. If your urine isn’t a very light yellow to almost clear, you are not drinking enough. To ensure your muscles have plenty of glycogen, 3-4 days prior to the event ensure that ⅓ to ½ of your plate is a carbohydrate such as rice or pasta. You can certainly eat bowl after bowl of pasta, as the old adage went, but aside from giving you a belly-ache it is unlikely to help your overall performance.

During the Event
In the half-marathon, most people do not need to worry about hydrating or eating. In fact, many people who come into the aid station after a half-marathon have problems from drinking too much water — not from being dehydrated! For hydration, a good guideline is to drink a little at each aid station and alternate between the electrolyte drink and water. For eating, I would recommend part of a gel or a few energy blocks about halfway through the event — if you feel like you need to eat at all.

The marathon is a little different. I would recommend drinking 4-5 ounces of electrolyte drink at each aid station and consider eating a little every 8 miles or so. 

The most important thing is to have a plan and to have tried that plan in training. Each person reacts differently when trying to eat or drink while running. And eating or drinking too much will simply make you feel sick — remember, all your blood is busy supplying the big muscles of your legs!

Running a half-marathon or a marathon is real accomplishment. The above ideas should provide a little guidance in preparing you for a successful and fun day. If you would like some more information, clarification or if your training has been unfortunately sidelined by injury, I or any of the Sports Medicine providers at Swedish Spine, Sports and Musculoskeletal Medicine would love to see you and get your training back on track.

Ronan Cahill, MD, is a Sports Medicine Physician at Swedish. Learn more about Swedish Spine, Sports and Musculoskeletal Medicine.

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This information is not intended as a substitute for professional medical care. Always follow your health care professional's instructions.

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