Skip to content

How to prepare for a marathon and support your immune system

Run a marathon with Move Free

Blisters, sore feet, heavy legs and… The sniffles?

Probably not a complaint you’d expect to have following a long run. But if you’ve ever run a marathon, you might be familiar with the common groggy feeling that many runners experience afterwards.

Even if you’re preparing for your first marathon, you may have heard about the prospect of a weakened immune system. But fear not; as thousands of people prepare to run the Boston Marathon, and look ahead to similar races over the coming months, we’re here to help.

In this article, we’ll look at some of the reasons why long-distance running can affect your immune system, and how you can protect yourself before, during and after the race.

Regular exercise is good for you and is shown to support immune function, as well as reducing the chances of colds[1].

However, prolonged exercise such as marathon runs may have the opposite impact. Studies have suggested that the immune system shows signs of weakening after a marathon or similar exercise. One study found that marathon runners were more likely to experience respiratory illness after the racing than a control group who led sedentary lifestyles[2].

And that’s not the only problem; issues can also arise during the training phase.

The relationship between exercise and the immune system

A further study showed that overtraining may lead to minor illnesses and respiratory issues.

But if that’s not enough to put you off, and you’re planning on going ahead with your marathon race, there are certain steps you can take to give yourself some protection, both before and after the big day.

How to train and prepare for a marathon

Ahead of any race, it’s imperative that you train. But how exactly can you prepare for a marathon?

Follow these tips to ensure you’re ready on race day.

Up your distance gradually (but remember to taper)

If you’re a novice runner, it can be hard finding the time to train. But if you’re serious about running a marathon, you need to make sure you train effectively.

Start by running at a comfortable distance, and slowly work your way up towards the race distance. In the weeks leading up to the race itself, you should ‘taper’[4]. This is where you gradually reduce the distance you train in the build-up.

You should workout only lightly in the week before the race, allowing you to restore your energy reserves ahead of the marathon.

Get some rest

Lots of exercise naturally leads to fatigue, so to avoid running on empty, you need to ensure that you get enough sleep. Sleep is important for you because it helps to conserve energy , which is vital when you’re preparing for a high-intensity event like a marathon.

There’s also an immune benefit to sleep; a lack of slumber has been shown to suppress the body’s immune function . That means it’s doubly important to catch your Zs during your marathon training schedule.

Stay hydrated (but don’t drink too much)

Everybody knows that it’s important to stay hydrated. When training for and running a marathon, you’ll lose plenty of fluids through your sweat. You need to replace these, so be sure to take on plenty of water.

One word of caution, though: don’t overdo it.

A study found 13% of a group of 488 Boston Marathon runners had sodium levels which were too low, with three of them having critically low levels . This was brought to attention by the sad death of one female racer, who passed away from hyponatremia (loss of too much salt).

These dangerously low sodium levels were linked to racers taking on too much water during the race. Experts recommend drinking around 5oz of fluid approximately every 20 minutes.

Post-marathon recovery tips

Once your race is run, and you’ve (hopefully) recorded a time you’re pleased with, it’s important to recover effectively.

Here are some recovery tips:

  • Rehydrate – Weigh yourself before and after the race to work out how much body mass you’ve lost. Drink 2-3 cups of water for every pound lost during the race
  • Have a massage – One study found that a massage can reduce the effects of delayed onset muscle soreness[8] after a marathon. Massage after exercise might also benefit your immune system as it can lead to an increase in infection-fighting white blood cells, as well as a reduction in the stress hormone cortisol, which is linked to decreased immune function[9]
  • Eat well – Diet is just as important after a workout as before. Eat something rich in carbohydrates, such as pasta, which will help to restore energy. Protein from chicken, fish or eggs can also help with muscle repair7
  • Rest – It goes without saying that your body will have come under stress during a marathon run, so ensure you take a few days out to rest and recover before you get back into your exercise routine

Ready to run? Just follow the tips above to prepare your body inside and out, and you’re good to go.

Good luck with the race!



[1] “6 Immune System Busters & Boosters” WebMD, Undated,

[2] Nieman, David C. “Risk of Upper Respiratory Tract Infection in Athletes: An Epidemiologic and Immunologic Perspective” NCBI, Oct-Dec 1997,

[3] “Chronic exercise training effects on immune function” NCBI, July 2000,

[4] Cooper, Bob. “It’s Taper Time” Runner’s World, 9 December 2003,

[4] “Why Do We Sleep, Anyway?” Harvard, 18 December 2007,

[5] Mann, Denise. “How Sleep Loss Affects Immunity” WebMD, 19 January 2010,

[6] DeNoon, Daniel J. “Marathon Runners Drink Too Much” WebMD, 13 April 2005,

[7] Brooking, Catherine. “The Best Fuel for Your Workout” WebMD, 2 March 2017,

[8] Zainuddin, Zainal. Newton, Mike. Sacco, Paul. Nosaka, Kazunori. “Effects of Massage on Delayed-Onset Muscle Soreness, Swelling, and Recovery of Muscle Function” NCBI, July-September 2005,

[9] “Massages Boost the Immune System” Live Science, 8 September 2010,

[8] Zainuddin, Zainal. Newton, Mike. Sacco, Paul. Nosaka, Kazunori. “Effects of Massage on Delayed-Onset Muscle Soreness, Swelling, and Recovery of Muscle Function” NCBI, July-September 2005,

[9] “Massages Boost the Immune System” Live Science, 8 September 2010,

BACK TO Immune Support