Science Weekly: heat stroke, sports washing, and the psychology of VAR: the science of the World Cup – podcast

This is the Guardian. It's just a week until the first whistle blows at the 2026 World Cup in North America and Mexico. Temperatures are set to be sweltering and a group of scientists is raising the alarm about the impact on players and the quality of the game. Heat is also on FIFA as campaigners call out their fossil fuel sponsorship. Is it another own goal for their climate strategy? And spare a thought for the refs? On top of the climate they're having to deal with a stepped up VAR system this year. How will it impact their decisions? Our football weekly colleagues asked us to look into the science of the World Cup and, well, how could we refuse? From the Guardian, I'm Madeline Finley and this is Science Weekly. Ian, thank you for joining me at this very special Football Weekly Science Weekly CoLab. Now, we're starting with something that might not be too familiar to the English and Scottish teams at least playing in the heat and this is actually something that's also got scientists worried. What are their concerns? Well, the predictions are that this could be the hottest World Cup ever or if not one of the hottest World Cup ever and that has prompted a group of doctors and scientists to write an open letter to FIFA because they're really concerned about the potential for harm to players and even, you know, match officials, the referees. I spoke to Dr Oliver Gibson. He's one of the signatories of this letter and he's a member of academic staff at Brunel University of London. He studies the impact of heat stress on human performance and I said to him, what is in this letter? We focused our letter and the research on a metric called wet bulb globe temperature, which encapsulates all of the environmental conditions that the players will experience. So it takes into account the air temperature of the environment that the players are playing in but it also acknowledges that heat stress goes beyond just temperature. So there's a need to acknowledge the impact of humidity on the players, the impact of solar radiation, so effectively feeling the sun on your skin and the heat stress that that imparts as well as the potentially helpful cooling effect that comes from airflow and the wind speed that the effects players. They worked out in about half a dozen of the cities where these matches are going to be played and we're talking about places like Dallas, Houston, Miami. This wet bulb globe temperature could hit 30 Celsius and that is brutal if you're playing football at the intensity that these elites are going to be playing at but there's also a concern about what this might mean for, you know, the spectacle of the world cup for the performance of the players. Right. So what exactly will these temperatures be doing to the players physically? Well, if you think about how the body calls down, obviously it calls down in a bunch of ways but the main way is through sweating. The body has to sort of dilate all the blood vessels near your skin and it pumps more blood through the those areas. So you have the blood near the skin and sweat on your skin. As that evaporates, it takes heat away from the blood okay. So that cooler blood then gets pumped back to the heart and circulated around the body. But if you think about it at the same time for these footballers, their muscles will be demanding an awful lot of blood as well. So those are in competition and you can get to the point where this calling just stops working. It doesn't do enough and that is when it hits performance and obviously carries these health risks as well. And you know, the worst case scenario is that you get heat stroke and that can be fatal. In that scenario, the body temperature has increased quite substantially. One maybe two or even three degrees Celsius above its resting levels. The body also has what we call a reflex response to increase body temperature. So we'll see redistribution of cardiac output or the blood flow away from what the body deems to be non-essential organs in that moment. So for example, the gutter gastrointestinal tract, the kidneys and the liver, that's not without complications in its own right. So one of the pathways towards heat stroke emanates from the gut. We see the gut become lower in blood flow and people develop this leaky gut syndrome. And with a leaky gut in players, what we see is bacteria that should be residing in the gut, move into the bloodstream and the body initiates then an inflammatory response to try and resolve those. It doesn't have sufficient blood flow to send those bacteria to the liver for clearing in that organ. And this inflammation contributes towards what ultimately can be fatal in heat stroke, which is multi-organ failure. So this is serious stuff. And beyond the health risks, Oliver talked about how heat can impact the game itself. We know that football matches played in higher heat stress conditions can seem a little bit more passive. They might be less engaging to the spectator. Players produce less high-speed running. They have the capacity still to sprint as fast, but they choose to sprint less frequently. So we might see in hot affixures around 10% less high-distance running. If you take an average player, it might cover 10 kilometres. That might drop off by around about 10%. The approach of the game might change substantially as well. Although there's some cognitive and decision-making declines that come with heat stress, we know that actually an interesting proxy to that pass accuracy tends to go up when the conditions are hot. And that reflects players making more conservative passing decisions to retain possession and avoid the need to do lots of high-speed running to recover the ball. There is a chance, I think the spectator might observe that the game's feel a little bit less thrilling for it, want to put better word. So bearing in mind all of that, what does Oliver want to see happening to mitigate some of these risks? So first of all, FIFA have said, look, our top priority is to ensure the health of the players, of the referees, of everybody involved in the World Cup. And they have introduced for this World Cup each match, regardless of the temperature, is going to have a calling break in each half. But what the researchers are worried about is that they say that the threshold for bringing in really serious mitigations, that would be delaying or postponing a match. They say that threshold is too high and at the moment for the World Cup, that would come in at this wet bulb globe temperature of 32 degrees. And these researchers say the recommendation should be 26 degrees. So they are looking for a substantial reduction in that threshold, where officials can just say it's too hot, we have to delay this game. But they also want to have some other changes made to, to spend longer periods than FIFA have currently mandated. They have a three-minute calling break, which potentially is insufficient and a six-minute break, would allow for more meaningful rehydration and calling. Potentially there is a scenario that we haven't really seen in football in the same way we might have seen it in endurance sports like marathon running, for example, where we receive pictures of a player collapsing in the game and there's a suspension of play, perhaps the temperature and the heat stress conditions mean that games have postponed and/or delayed in game for substantial periods of time. All of those are really concerning. Just finally, Maddie, we're now seeing players who've written their own letter in support of this to try and get FIFA to listen and so hopefully that will add some weight to it. And so if there are any coaches or players listening, what should they have been doing to prepare for this heat? Well luckily Oliver did his PhD on how to acclimatise to heat. So he's a good guy to go to. He says that in a couple of weeks of specific training in hot conditions, the body can learn to cope a lot better with this and we're talking about training in hot environments, training in sort of heated facilities if you need those and even bringing in things like saunas and baths into your training programme. Maddie behind these soaring temperatures is of course the climate crisis and you know there's some irony in the fact that one of FIFA's main sponsorship partners is Aramco, this huge Saudi oil and gas company. Tell me a bit about this. Yeah so FIFA signed this global partnership with Aramco, this huge fossil fuel company. This does cover the world cup as well. And Aramco are actually the sponsors of Houston, host city. So fans are going to be seeing Aramco's name everywhere. Now you might argue that this is a pretty clear example of sports washing so that's when companies sponsor athletes or events to kind of improve their reputation, bearing in mind Ian all that you've been telling me about in terms of the heat. I think there are lots of fans who are going to be not very impressed with this. The environmental impact of these sorts of events very often you see it from flights you might see like in Qatar when there were stadiums being built but the impact of advertising is much more subtle but there is an impact. I mean they wouldn't do it if there wasn't. Now I chatted to Peter Chris, he's a company painter at Fossil Free Football. It's a grassroots organisation of fans and he said that seeing all the advertising of polluting companies made him feel like football was on the wrong side of things and actually the beautiful game or the people in charge of it really needed to start taking this seriously. So what are FIFA's commitments to tackling emissions in football? FIFA have committed to the global goals of the 2015 Paris Climate Agreement. So they've pledged to achieve a 50% reduction in their carbon emissions by 2030 and they've also pledged that they're going to reach net zero by 2040. They have a climate strategy and one of the things that this climate strategy is supposed to do is to protect FIFA's tournament games and that's from things like heat, from flooding, from extreme events. So it could even be things like smoke from wildfires. But in their choice of sponsors aside, there are a few things that are going to make it hard for FIFA to argue that this World Cup is in line with that strategy and that's because they've massively increased the number of teams in this World Cup. So it's gone from 32 in Qatar to 48. So that's many more games being played in the stadiums across three countries, the US, Canada, and Mexico. So what kind of impact will this World Cup have on the environment? It's going to be pretty significant. So the organisation, scientists for global responsibility, they've calculated that this World Cup is likely to generate more than 9 million tonnes of carbon dioxide equivalent, making it the most polluting World Cup ever. And they've also calculated that this is about the same as 6.5 million average British cars driving for an entire year. So that really puts it into some context. And most of those emissions, the majority really are going to come from the flights. So that's fans flying in from around the world and then flying between matches as well, no flying between the three different countries. And look, if you want a big global event like this, some of that is obviously totally inescapable, but if fans in the Northern Hemisphere want to keep these summer tournaments, organisations like FIFA are going to have to start bringing down these carbon emissions because the summer is becoming less and less viable to host these tournaments. I mean, us in the Northern Hemisphere, we love going to big gardens to watch the games, you know, around the games going to parks, having a barbecue. And if the heat is really kind of repressive, that becomes less and less enjoyable. But also for the players, like you've said, for the staff, for the fans in the countries where this is being hosted, when there is this extreme heat, it's not safe. And sure, you can move the games to further in the evening and you can introduce these hydration breaks. But at some point, it just isn't going to be enough. But bearing in mind, this is likely to be an extremely hot world cup. Do you think this is going to kickstart that conversation in football again? This is obviously what campaigners like Peter Crisp are hoping for. I'm sure he wishes that they didn't have to have these conversations because he pointed out to me that, you know, there are billions of football fans around the world. And so there are billions of them who really care about the climate crisis and want to see strong policies put in place to protect the game that they love. And I do wonder if the fans are going to struggle this year in the heat themselves or if there are other extreme weather events that begin to really disrupt games. This is going to be on the agenda. And Ian, the next world cup is in 2030. So we can imagine what the temperatures might be like then. And the hosts are Morocco, Spain and Portugal. So this problem is certainly not going anywhere. Coming up, the psychological impact of VAR for referees and fans. Ian, did you know that studies have shown that heat makes people more aggressive and angry eye for one can attest to that? But there's something else that is potentially going to get fans blood boiling at this world cup. And that is, of course, VAR. Recently, there was a study on VAR that you've been looking into. What's this about? This all came about when a guy called Dr. Daniel Walker. He's a researcher in psychology of sport at the University of Bradford. And he was watching a football match with his dad when the referee was called over to do, you know, a long field review where they go and look at the screen in full view of everyone. And his dad goes, ah, this decision is going to be overturned. And Daniel was like, yeah, I bet it is. And it was. What Daniel thinking about, is there anything that happens in the fact that the game is stopped and the referee is told to go and look at this evidence again because VAR has decided that, you know, he may have missed something. Are you kind of psychologically primed to think, yeah, I got that call wrong? So Daniel looked at more than 1500 matches in the English Premier League from the last few seasons. And they found about 250 occasions where the referee been called over to do one of these on-field reviews. And when they looked at how often those overturned the referee's original decision, it was 95% of the time. So clearly, if you're sitting there watching a match and VAR says, "Reth, come and have a look," the chances are that that decision will be overturned. So what does this say about the impact that VAR has on referee's decision making? Well, first of all, I think we need to sort of think about how VAR, the video, a system referee, is there to spot clear and obvious errors or serious missed incidents, right? And this obviously a team of people who have the benefit of multiple camera angles, they have the benefit of replays. And so when VAR says to a referee, we think you should take a look at a particular incident. The chances are that they have got a good sense that something important has been missed, okay? And the big sense is not a surprise that these decisions are overturned. Now how often should they be overturned? I mean, that's really hard to say because a lot of these actual on-field reviews, they're often those fine decisions that keep football fans talking, football fans talking about them for years, right? And they're the sort of, you know, the lifeblood of these post-match phone-in sessions you get on the radio, right? But there's definitely some psychology here because if VAR implies that you've made a wrong call, that's going to be hard to ignore. You can either double down and risk making the wrong decision twice, or there will be a natural temptation to just, you know, shift some of that responsibility to VAR. And I think there is that temptation. Now obviously VAR is not remotely universally popular. And you know, among the critics that are out there is Alan Scheer who thinks that refereeing has gone downhill because of VAR, because he thinks that referees are becoming too reliant on VAR and too reliant on the decisions they make. I do think that's really interesting because if you have a decision where ultimately it is a bit of a gray area, you're the ref on the pitch, you've got this huge pressure around you, it would be so difficult to go against the VAR, I think. So yeah, an interesting issue, but what about the fans? Obviously, VAR puts a dampener on, you know, if your team scores in the final minute, that goal really has to count, but you don't know if it counts. So what do you do? Do you celebrate twice? Do you sort of celebrate when the goal goes in because you can't help it? Sort of one celebration out of joy. And then a second celebration out of relief when VAR actually says, yeah, the goal stands, or you have this situation where you celebrate because the goal's gone in. And then you have this sort of pretty swift crushing blow of the decision being over term. So all of that obviously adds to the frustration. Some people might say it adds to the excitement as well, but it certainly can be frustrating. But look, I think there's plenty of discussion still around whether VAR does something else to the game, which is actually undermining the authority of the referee because, you know, in the old days when you're watching a match, the referee would make a call and everybody would like, you know, throw their arms up, it went against them, but you would know that the referee's made a decision, that decision is final and the game goes on and, you know, over time, these bad decisions, they even out and it's all part of the game. But now, you know, the referee's decisions can start to seem a bit provisional and it undermines you thinking that referee is competent, that they are in charge of the match. And I think those things do end up sort of leaving people that maybe, you know, who's running this game? Is it VAR and the referee's just going along with it or is it the referee who has this by the scruff of their neck? And I think that can change how we perceive these games in quite subtle ways. And going back to Daniel and his dad, the fact that this study has shown that when VAR is called, it's overturned 95% of the time. I mean, there's an element of the moment you see that box being drawn by the ref, you're going to be thinking, uh-oh. Totally. You go to these heart-stopping moments because you think, yes, we've got the goal or we've let one in. And then you see the VAR. Sometimes it gives you an extra cheer. Sometimes you just have your head in your hands again and you are cursing VAR as as the devil's technology. And, you know, we have a long period to see how this goes now with the World Cup. - Absolutely, I will be watching it. I know that Daniel is as well. I know that he's gonna do yet another study, right? - It's a research opportunity. (laughs) - It's always a research opportunity, isn't it? Ian, thank you so much. - Thank you. (soft music) - Thanks again to Ian. And if you're not already a listener to Football Weekly, hit subscribe now to keep up with all the matches and excitement of the World Cup. You can also follow all our World Cup coverage at TheGuardian.com. This episode was produced by me, Madeline Finley. It was sound designed by Ross Burns and the executive producer is Ellie Bury. We'll be back on Tuesday. See you then. (soft music) This is TheGuardian. (soft music)