Participant of the 4Days Marches? Here is some advice Make the most of the 4Days Marches preparation with advice from Maria Hopman

In just four weeks, the 4Days Marches in Nijmegen will kick off again, with over 45,000 walkers at the start. Good preparation is very important to complete the four days successfully and stay healthy. Based on research and experience, physiology professor Maria Hopman from Radboud university medical center shares four practical tips. From training in the heat to staying hydrated—this is how to prepare your body for the challenge.

Train in all conditions, including heat

With warm weather expected this weekend, it’s the perfect time to train, says Maria Hopman. ‘It’s wise to train in all weather conditions, including high temperatures,’ she explains. This gives your body a chance to adapt. The human body is naturally well-equipped for heat—our ancestors lived on hot savannas. And the body adapts surprisingly quickly. ‘Regular training in the heat teaches your body to handle it more efficiently: you start sweating earlier and your heart rate stays lower. Those who are used to heat perform better when it counts,’ says Hopman.

Practice walking two days in a row—with food and breaks

Hopman also recommends training on two consecutive days to see how your body responds. ‘You don’t need to walk the full distance, but treat it like real 4Days Marches stages, including practicing your rest breaks.’ She advises taking a 10-minute break every two hours. ‘No longer, or you’ll stiffen up and it’ll be harder to get going again.’

Also consider your nutrition during walks. ‘On long walks, hunger often disappears because the hunger hormone is suppressed, blood flows to your muscles instead of your digestive system, and drinking a lot gives a feeling of fullness. But you still need extra energy when walking 30, 40, or 50 kilometers. Bring enough food and alternate between sweet and savory snacks to keep your energy levels up.’

Check how much fluid you need

If you notice you’ve lost a few kilos after a training day, that’s no reason to celebrate, warns Hopman. ‘One day of walking doesn’t lead to lasting weight loss; it mostly means you’ve lost fluids—and probably didn’t drink enough.’ Research during the 4Days Marches showed that 20% of participants don’t drink enough, which can harm performance and pose health risks.

That’s why training is the perfect time to understand your personal fluid needs, which vary per person and depend mainly on how much you sweat. There’s no one-size-fits-all advice. Want to know how much you should drink? ‘Weigh yourself before and after a training session and track how much you drank. The difference in weight shows how much fluid you lost. By doing this regularly, you can train your body to follow a healthy drinking pattern and avoid problems during long walks,’ says Hopman.

Choose your gear carefully—no last-minute changes

Hopman also advises against switching shoes at this stage: ‘New shoes won’t be broken in on time and increase the risk of blisters and injuries during the 4Days Marches.’ The same goes for backpacks or hip bags: train with the gear you plan to use during the event. Don’t decide the day before to switch to a backpack—it could lead to back or shoulder issues.

Finally, Hopman recommends thinking carefully about your clothing. In 2023, she studied whether white clothing is really cooler than black, after receiving questions from walkers. Inspired by Bedouins who wear dark clothing in the desert, she wanted to test the common belief. The result? ‘At temperatures below 25°C, there was no difference in heat perception or body temperature between white and black clothing.’ Her advice: ‘Choose clothing that’s comfortable and allows you to move freely. The color matters less than you might think.’ She plans to repeat the study in hotter conditions and also examine the effects of wearing a hat or head covering.

Want to know more about the 4Days Marches research of 2025? Check out this page.

• Want to know more about these subjects? Click on the buttons below for more news.

  News homepage news & media