How to Train for a Marathon: A Beginner’s Guide

    Updated 17 June 2019 |
    Published 17 April 2019
    Fact Checked
    Reviewed by Kate Shkodzik, MD, Obstetrician and gynecologist
    Flo Fact-Checking Standards

    Every piece of content at Flo Health adheres to the highest editorial standards for language, style, and medical accuracy. To learn what we do to deliver the best health and lifestyle insights to you, check out our content review principles.

    If you’ve developed a new running habit, chances are you’ve already started looking into races to add to your calendar. Whether you’re aiming to start with a more manageable 5k or you’re going all-in for a full marathon, a few months of preparation and training will ensure you’re ready to conquer the distance.

    Keep reading to learn how to train for a marathon.

    How long does it take to run a marathon?

    Preparing for a marathon can take a significant amount of time, but it’s impossible to know exactly how much time it will take to run one. In general, though, the time it takes to complete a marathon (or any long run) depends on a variety of different factors:

    • Distance
    • Course difficulty
    • Crowds on the running course
    • Weather conditions
    • Your nutrition and hydration
    • Your running experience
    • Your average pace

    Though the official distance of a marathon is about 42 km (26 miles), most races offer a range of distances to suit all levels of runners.

    A 5 km (3.1 miles) race. This race is an ideal entry-level race. The distance is short enough that even beginners, with the right amount of training, can be ready to compete in a few months. If you’re new to the 5 km race, you might wonder: how long does it take to run a distance like this? Many runners find that a good finishing time is anything under 25 minutes. If you’re a walker, you’ll probably finish a 5k in 45 to 60 minutes. 

    A 10 km (6.2 miles) race. If you have some running experience under your belt, you may want to try running the 10 km marathon. But how long does it take to run a marathon of this distance? Although it’s impossible to predict the exact running time, the average runner with a few months of regular training can finish it in 60–70 minutes. If you’re a jogger or quick walker you might be able to finish it in 70–80 minutes. 

    A half marathon (21 km or 13.1 miles). Running times for a half marathon range from a little over an hour for professional runners to over three hours for slower runners or walkers.

    Marathons (42 km or 26.2 miles). Running times for marathons range from over two hours for elite athletes to six or more hours for those who run slower or prefer walking.


    How to train for a marathon 

    Before investigating how to train for a marathon, it’s important to consult with your physician. If you get a thumbs up, consider following a training plan to guide you through your journey. Don’t forget that your diet is just as important as your exercise training, so plan to follow a nutritious diet program as well.

    Training plan

    Full marathon training is essential, especially if you’re a beginner. If you don’t have much experience running marathons, then you should start preparing six months before the big day. Aim to run 20–24 km (12–15 miles) per week. Preparing for a marathon is crucial, as your body needs time to adapt physically to the pounding that it will be taking during both training and the race. 

    The ideal full marathon training plan should have:

    • Three runs per week
    • Two cross-training days (biking, swimming, hiking)
    • Two rest days
    • The running should be a combination of a short/fast run, a medium run, and a long run
    • Choose your days as you prefer, but make sure you have a day of rest on either side of the long run


    If you’re a first-time marathon runner, you might be wondering ‘What gear do I need when running?’ Yes, preparing for a marathon also includes equipping yourself with the right gear. The good news is that you don’t need a lot of equipment, as running is a pretty low-maintenance sport. However, if you want to make sure you’re safe and have no troubles finishing the marathon, here are some essential items to consider: 

    • Shoes. Look for a well-cushioned pair of running shoes that fit you well. They should be specifically for running — not cross-training or any other sport. A good pair of shoes will help prevent running injuries and make for a more comfortable experience.
    • Clothes. You might want to buy running socks, supportive sports bras, leggings or running shorts, and a t-shirt or tank top that wicks away sweat. Avoid cotton fabrics and look for synthetic materials instead.
    • Running accessories. Good running gear can make a huge difference in the quality and safety of your runs. Consider a watch, running belt, armband carrier, visor or hat, UV-blocking running sunglasses, and sunscreen. 
    • Water. If you don't have access to water on your running routes, you’ll want to bring your own water bottle with you. Carrying things when you run can be a pain, so there are belts designed specifically for this purpose. 


    Preparing for a marathon requires a combination of regular exercise and proper nutrition. Start following a nutritious diet plan at least ten weeks before the big event. Here are a few tips to help you stay in shape.

    Eat more carbohydrates. Carbohydrates are the body’s primary source of fuel. They should make up 60–70% of the total calories you eat in a day. Aim to consume more complex carbohydrates and less simple sugars, as they are digested more slowly and give you longer lasting energy. These complex carbohydrates include whole grain breads and pastas, cereal, brown rice, oatmeal, and vegetables. 

    Fat and protein. Let’s not forget the other two main macronutrients, as they also form an important part of a balanced pre-marathon diet. Protein is essential for muscle growth and should make up about 15% of your total calories per day. You should consume less than 30% of your total calories from fat. Be sure to choose healthy fats, including from avocados, nuts and seeds, and oils like coconut, avocado, or olive oil.

    Hydration. In addition to a meal plan, it’s crucial to consider hydration. Water should be your primary source of hydration and you should strive to drink at least 6 to 8 glasses of water every day. If you’re running longer distances, you might want to add in sports drinks to help replenish your electrolytes.

    Mental preparation

    Preparing for a marathon doesn’t just include training and healthy nutrition. Getting your mind ready to face the distance — whether it’s 5 km or 42 km —  is equally as essential. One study by Staffordshire University in the UK discovered that mental toughness accounts for 14% of racing success!

    Here are a few tips to help you get in tip-top mental shape:

    • Practice mindfulness to mentally prepare for a marathon
    • Run with your friends — it’s more fun and motivational
    • Pick a short phase that you will play in your head while running to help you stay focused 
    • If you're feeling anxious about the marathon, talk to friends who have run a race to exchange ideas and support
    • Reward yourself once in a while for your hard work, like with a massage or new running gear
    • Remind yourself of the health benefits of running

    How long does it take to train for a marathon? 

    If you’re in a healthy condition, you can go from couch potato to marathon with about 6 months of training. However, it’s important to transition in baby steps. Begin with 5 km, then move to 10 km, and slowly progress towards a half marathon before you tackle the full marathon distance.

    Preparing for a marathon can be an intense experience — but it can also be life-changing. Being active in this way tends to remind you how much better life is when you’re regularly training, maintaining a healthy diet, and setting goals. So, when the day of the marathon finally arrives, remember your training plan. Stick to your pre-run diet, wear your most comfortable pair of running shoes, and get a good night of sleep beforehand. Don’t start out running too fast, stay relaxed when things get hard, and run across the finish line knowing that you just completed an incredible athletic achievement!

    History of updates

    Current version (17 June 2019)

    Reviewed by Kate Shkodzik, MD, Obstetrician and gynecologist

    Published (17 April 2019)

    In this article

      Try Flo today