The city of Berlin is famous for its wall. But while you might automatically think about the historic concrete barrier that previously divided the city after World War II, we’re talking about the wall – the one that many runners hit during the Berlin Marathon each year. This is the woeful wall that, quite literally, stops you in your tracks – your legs feel heavy, your energy has crashed and you start to doubt that you’ll ever see that finish line.

Both Berlin walls symbolise struggle and conflict. But it’s the running one that we are focusing on here, because according to a new study, men and women have very different experiences when it comes to ‘hitting the wall’ during a marathon. Here’s what the researchers found – and why men tend to encounter the wall most frequently.

What did the study involve?

The researchers wanted to determine whether a person’s sex influenced their likelihood of experiencing ‘catastrophic deceleration’ – that is, hitting the wall – during long-distance running events. To do so, they looked at a massive dataset of 873,334 Berlin Marathon finishers from 1999 to 2025 and analysed how each runner’s pace changed between the first and second half of their respective race. To be clear, ‘catastrophic deceleration’ (I’m using that in future) was defined as a slowdown of 20% or more in the second half relative to the first.

On average, the researchers found that women slowed down by 8.34%, while men slowed down by 10.73%. However, the discrepancy grew when it came to ‘catastrophic deceleration’: on average, 9.66% of women hit the wall, versus 17.63% of men. In other words, exactly twice as many men hit the wall as women.

Faster speeds mean harder crashes

Interestingly, faster men tend to fare the worst when it comes to hitting the wall, compared to their women counterparts. Specifically, the study found that 1.42% of men who ran sub-3-hour times hit the wall, while a mere 0.23% of sub-3 women finishers bonked during their race. This means that, among sub-3 finishers, men are six times more likely to hit the wall than women. This holds true for sub-3 finishers across all age categories, too.

Slowdowns are consistent

The Berlin Marathon was specifically chosen as the study’s testing ground because of its ‘flat profile and consistent conditions’, which meant that the researchers could ‘isolate sex as a variable, minimising topographic confounders’. And although we have anomalies like the 2025 Berlin Marathon, where temperatures were unseasonably scorching, the researchers found that men reliably hit the wall more than women in 26 consecutive races over 27 years. (The 2020 race did not, of course, take place.) As such, no unusual weather conditions and no emergent training strategies, tech or nutrition impacted the overall pacing outcomes of men and women over this time period.

Why do men bonk more often than women?

The researchers gave two possible reasons for this.

The first reason is grounded in science. The researchers noted that, compared to men, women have more slow-twitch, endurance-suited muscle fibres than men. Women also burn more fat than men during endurance events and, as a result, can spare glycogen for longer. Don’t forget that you hit the wall when you run out of glycogen.

The second reason is speculative and based on behavioural patterns. For some men, the researchers note, ego and a need for (initial) speed gets in the way of efficient pacing.

‘Emerging evidence from sports psychology and behavioural economics suggests a paradox: while men are physiologically faster [than women], they may be behaviourally less efficient,’ write the researchers. ‘Theoretical models of decision-making under fatigue propose that men may display higher tendencies toward ‘risk-taking behaviour’ and ‘overconfidence’, which could contribute to aggressive initial splits that often prove unsustainable. In contrast, female runners are frequently hypothesised to possess superior self-pacing abilities and greater resistance to decision-making fatigue.’

The researchers said it, not me.

How to avoid hitting the wall

Despite the study’s findings and irrespective of your sex, you can do things to reduce your chance of hitting the wall during your next marathon. Here are four key areas to work on.

1. Fuel properly during the race

Mid-marathon fuelling is non-negotiable if you want to avoid an encounter with the wall. Don’t even try to dispute it. So, use your long training runs as an opportunity to test the type of fuel that sits well in your stomach – whether that’s a specific energy gel, drink or chew – and how frequently you need to take it. Then, once you’ve found a nutrition strategy that keeps you feeling strong (and is gastro-friendly) for the duration of your biggest training sessions, lock it in and replicate it on race day.

As a benchmark, sports dietitian Renee McGregor recommends aiming for 30-60g of carbohydrate per hour for the first three hours of your marathon, then increasing to 60-90g of carbohydrate per hour after that.

2. Fuel properly before the race

What you eat before your marathon also matters – and that’s where carb loading comes in. In the two or three days before your race, start to consume more carbohydrate-rich foods so that glycogen can start to accumulate in your muscles. According to sports nutritionist Ilana Katz, 85-95% of your calories should come from carbohydrates during this carb loading period.

A problem is that runners often over-consume calories during the carb loading phase, which leaves them feeling sluggish rather than raring to go. To avoid this, cut back on protein-rich foods – which are filling but lacking on the carbohydrate front – and replace them for foods like rice, bread, pasta, porridge and so on.

3. Stay hydrated

Proper hydration helps to prevent early fatigue, replace water lost through sweat and regulate core body temperature, so never underestimate the power of drinking enough water. Before your marathon, aim to drink the recommended daily intake of 2L. Then, during your marathon, aim to consume anywhere between 300ml and 800ml of water per hour, depending on factors like the outside temperature, how much you sweat and your thirst. If you’ve trained with them, consider adding electrolytes to restore sodium levels.

4. Pace yourself

This really is easier said than done, especially at the start of a race when you may find yourself surrounded by countless other runners who channel all their nervous/excited energy into going off too hot. Try to start your marathon at a pace that feels comfortable – easy, even – to prevent you from burning through your glycogen stores too quickly. Then, if you feel good and in control, you can pick up the pace as the miles progress and aim for a negative split.

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