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Contrary to what scientists once thought, even superficial cooling is enough to interfere with muscle oxygen supply.

The human body is an engine with efficiency similar to a car engine. In both cases, about three-quarters of the energy consumed is released as heat. That’s why it’s easy to heat the interior of a car: just blow some of that heat from the engine into the cabin. And it’s why endurance athletes worry a lot about getting too hot but mostly view cold as a minor annoyance rather than a fundamental limit on performance. If you’re pushing hard enough, you won’t be cold for long—right?

But new research published in the Journal of Applied Physiology suggests that cold really does diminish endurance performance. That’s contrary to what some previous research has found, but those earlier studies often involved volunteers who were ushered into a cold room and then immediately asked to exercise without waiting for their body temperatures to drop. In the new study, the volunteers got cold—and then stayed cold, no matter how hard they exercised. That’s a lesson that winter athletes will want to keep in mind next time they’re lingering in frosty air before a workout or a race.

The study was led by Phillip Wallace as part of his doctoral work in Stephen Cheung’s Environmental Ergonomics Laboratory at Brock University in Canada. Cheung is a serious cyclist whose lab has produced a bunch of interesting endurance-related research that I’ve written about previously on topics like heat, hydration, and self-talk. Cold research, on the other hand, usually focuses on safety-related topics like hypothermia and frostbite.

The new study compared cycling performance in four different conditions. In the control “thermoneutral” condition, the subjects sat in a temperature-controlled chamber set at 72 degrees Fahrenheit (22 Celsius) for 30 minutes. Then they started cycling with five minutes of warm-up at 100 watts before pedaling to exhaustion at 70 percent of VO2 max, which took on average just under 24 minutes. In the “cold shell” condition, the chamber was set to 32 degrees Fahrenheit (0 Celsius) and a wind speed of about one meter per second was added. Half an hour in these conditions was enough to significantly decrease skin temperature without dropping core temperature (as measured with a rectal thermometer) before starting the cycling test.

For the other two conditions, the subjects—ten men with an average age of 27—stayed in the 32-degree Fahrenheit chamber for long enough to drop their core temperatures by 0.9 or 1.8 degrees Fahrenheit (0.5 or 1.0 Celsius) before cycling, imposing mild hypothermia. Because of differences in body size, shape, and composition, people cool at different rates, but on average it took 116 minutes to reach the first threshold. For the second threshold, the average was 160 minutes, though three of the subjects didn’t cool all the way before hitting the maximum cooling time imposed by the research ethics board. During all the cooling trials, the subjects wore a T-shirt or cycling jersey and cycling shorts plus earmuffs, winter gloves, and a fleece blanket around their shoes—added warmth that turned out to be necessary during pilot testing.

There are a bunch of reasons you might expect endurance to suffer in the cold. Even with just a cold shell, your peripheral blood vessels will constrict, decreasing the flow of oxygen to your muscles. Cold also has more subtle effects on the chemistry of how oxygen is transported in the blood. And once you start shivering, you can burn a substantial amount of energy: in this study, the metabolic heat generated by the subjects doubled from the equivalent of about 10 percent of VO2 max in the thermoneutral condition to 20 percent in the hypothermic conditions. Shivering can also interfere with muscle contraction and coordination, and may even fatigue the muscles themselves.

Despite all these negatives, previous studies with similar cycling tests at 70 percent of VO2 max found that performance in 37 to 39 degrees Fahrenheit was either unaffected or even improved compared to moderate temperatures. Wallace’s results with pre-cooling were dramatically different, though. Time to exhaustion on the bike dropped from 23.8 to 16.2 minutes in the cold shell condition, 8.5 minutes in the first hypothermia condition, and 6.5 minutes in the second one. The results provide clear evidence that skin cooling alone is enough to reduce endurance by about 30 percent, and core cooling takes away another 30 to 40 percent.

It’s interesting to look at how the core temperatures evolved over the course of the time trials. Here’s a graph showing changes in temperature for thermoneutral (TN), cold shell (CS), and the two hypothermia (HYP) trials:

For both thermoneutral and cold shell, core temperature rises steadily through the time trial, as you expect from running a heat-generating engine to its limits. For the two hypothermia trials, on the other hand, the curve is almost flat, even though they’re cycling at exactly the same power output in all four trials. In fact, the core temperature even decreases during the first quarter of the trial, perhaps because warm blood is being pumped to peripheral muscles and cold blood is being shunted back to the core. The nuances of how heat is stored and moved around within the body are complex, but the upshot is that even cycling to exhaustion isn’t enough to warm you up if you’ve lingered for long enough in temperatures around the freezing mark.

One variable that’s hard to control is the mental effects of sitting around in a cold chamber for several hours. Physiology aside, you have to imagine that in those trials, the subjects just wanted to go home rather than ride a bike. As expected, their pre-ride motivation was lower, dropping from an average of three on a four-point scale in the thermoneutral trial to 2.5 and 2 in the hypothermia trials. Their initial perception of exertion when they started riding was also higher: 12 and 12.5 rather than 9.5 on the Borg scale, which measures exertion on a scale from 6 to 20. But by the end of the ride, the riders hit a max of 20 in all four conditions—so it’s not like they were unable or unwilling to push themselves.

The revelation that being really cold is bad for endurance may not seem that surprising. The most interesting distinction here, I think, is between exercising in the cold and being cold before you start exercising. One of my pathological neuroses as a runner is the fear of hearing the starting gun fire while I’m still wrestling to get my sweatpants off over my racing shoes. As a result, I often strip off my warm-ups well before the start even in sub-freezing temperatures. If there’s one idea I’ll take away from Wallace’s research, it’s that I need to invest in some tearaway pants.

Ethiopia delivered a remarkable double victory at the 2026 Bank of China Hong Kong-Zhuhai-Macao Bridge Half Marathon on Sunday, November 15, with Wede Kefale and Addisu Gobena emerging victorious in the women's and men's races respectively.

Staged along the spectacular Hong Kong-Zhuhai-Macao Bridge, the event brought together some of the finest distance runners from Ethiopia, Kenya, South Africa and other nations for a fiercely contested 21.097-kilometre challenge across one of the world's most recognisable sea-crossing structures.

The competition produced impressive performances, with Ethiopia showcasing its depth in distance running while Kenyan athletes also secured several places among the leading finishers.

In the women's contest, Kefale produced a composed and determined performance to secure the biggest prize of the day. She crossed the finish line in 1:09:01, holding off a strong challenge from South Africa's Glenrose Xaba, who finished second in 1:09:09. Ethiopia's Fantu Worku completed the podium in 1:09:14, making it an exceptionally close battle among the leading three women, who were separated by just 13 seconds.

The Ethiopian victory was particularly impressive given the quality of the field. Xaba, one of South Africa's leading distance runners, pushed hard throughout the contest but ultimately had to settle for second, while Worku demonstrated Ethiopia's remarkable strength by securing another podium position.

Kefale's victory was supported by an impressive Ethiopian presence throughout the top 10. Baraky Redae finished fourth in 1:09:51, followed by compatriot Asmarech Anley in fifth with 1:10:21. Kenya's Miriam Chebet was sixth in 1:11:05, ahead of Morocco's Fatima Ezzahra Birdaha, who clocked 1:11:23. Kazakhstan's Daisy Jepkemei placed eighth in 1:11:42, while Ethiopia's Zewudie Wudu finished ninth in 1:12:08. Kenya's Priscah Jepleting Cherono completed the top 10 in 1:12:29.

The men's race provided another memorable moment for Ethiopia as 22-year-old Addisu Gobena claimed the overall victory, He clocked 1:01:33 to finish ahead of compatriot Aliyi Kasim, who secured second place in 1:02:29.

Kenya's Alex Lenalepisho delivered a strong performance to take third in 1:02:47, preventing a complete Ethiopian sweep of the men's podium. Morocco's Othmane El Goumri finished fourth in 1:03:07, while Kenya's Abel Kiplimo followed in fifth with 1:03:33

Kenyan representation remained particularly strong throughout the men's top 10. Ezra Kipketer Tanui finished sixth in 1:05:32, followed by Ethiopia's Tafere Adisu in seventh with 1:05:35. Kenya's Meshack Kipchirchir placed eighth in 1:06:01, Benard Kipkorir was ninth in 1:06:15, and compatriot Sena Ledama completed the top 10 in 1:06:21.

Gobena's triumph adds another impressive achievement to Ethiopia's growing presence on the international road-running circuit, while the performances of Kasim and Lenalepisho underlined the competitive depth of the men's field.

The 2026 edition was also significant for the event itself, having earned World Athletics Platinum Label status, placing it among the highest-rated road-running competitions internationally. The bridge provided a spectacular setting for the contest, bringing together elite athletes from different countries for a memorable day of long-distance racing. 

Beyond the podium, the results highlighted the international character of the competition, with athletes from Ethiopia, Kenya, South Africa, Morocco and Kazakhstan featuring prominently in the leading positions.

Ethiopia therefore left Hong Kong with both overall titles, while Kenya had plenty of reasons to take encouragement from its strong representation across both races.

For the organisers, the successful staging of this Platinum Label competition represents another important milestone in the development of road running in Hong Kong. For the athletes, it was an opportunity to test themselves against international opposition on a distinctive course that offered a memorable backdrop to the racing.

American sprint sensation Noah Lyles could be preparing to chase one of the most extraordinary achievements in athletics history after dropping a tantalising hint about his ambitions for the 2027 World Athletics Championships in Beijing, China.

The four-time world 200m champion has sparked excitement among athletics fans after sharing a cryptic message on social media reading “4x ? 2027”, raising speculation that he could be targeting an unprecedented four gold medals when the global championships return to the iconic Bird’s Nest Stadium.

Although Lyles has yet to confirm exactly which events he intends to contest, the possibility of a four-event campaign has become particularly intriguing following World Athletics’ announcement that the mixed 4x100m relay will make its World Championships debut in Beijing.

Such an opportunity could open the door for the American superstar to compete for gold in the men's 100m, 200m, men's 4x100m relay and the newly introduced mixed 4x100m relay.

For Lyles, Beijing could represent much more than another opportunity to add to his impressive collection of championship medals. It could be the stage where he attempts to establish himself as the most successful male athlete in World Athletics Championships history.

The 100m would undoubtedly be one of his biggest attractions. Having claimed the world title in Budapest in 2023 before completing his remarkable rise to Olympic glory at the Paris 2024 Games, Lyles knows exactly what it takes to rule the world's premier sprinting stage. However, he will be eager to reclaim the global crown after settling for bronze behind compatriots in the 2025 World Championships in Tokyo.

The 200m, meanwhile, remains his strongest territory. Lyles has established an extraordinary legacy over the half-lap distance, winning four consecutive World Championships titles in 2019, 2022, 2023 and 2025. In Tokyo, he matched Usain Bolt's remarkable achievement of four successive world 200m crowns, further strengthening his reputation as one of the greatest performers the event has ever witnessed.

His ambitions would also extend to the relays, where he has repeatedly demonstrated his value to Team USA. Lyles has already collected four World Championships gold medals in the men's 4x100m relay, including victories in 2019, 2022, 2023 and 2025. Another successful campaign in Beijing would provide an opportunity to add to that impressive record.

The introduction of the mixed 4x100m relay could make the challenge even more fascinating. With the event officially scheduled to make its World Championships debut in Beijing, the competition will offer another opportunity for the world's leading sprinters to showcase their speed on the global stage.

Beyond the possibility of four gold medals, however, there is an even bigger historical prize waiting for Lyles.

The American currently boasts eight World Athletics Championships gold medals. Winning four more in Beijing would take his career tally to 12, moving him beyond Jamaican sprint legend Usain Bolt, whose 11 world titles remain the benchmark for male athletes in the competition's history.

That would be a remarkable achievement for an athlete who has never hidden his admiration for Bolt and his desire to reach the heights established by the Jamaican legend.

Interestingly, the Bird's Nest Stadium carries its own special place in sprinting history. It was at the same venue during the 2008 Beijing Olympic Games that Bolt announced himself to the world with his breathtaking performances in the 100m, 200m and 4x100m relay. Nearly two decades later, the iconic stadium could provide the setting for another extraordinary chapter in sprinting history.

For Lyles, the challenge will be enormous. Successfully navigating four demanding events, managing the competition schedule and delivering at the highest level across individual and relay races would require exceptional preparation, consistency and teamwork.

Nothing has yet been confirmed regarding his participation in all four disciplines, but his intriguing message has certainly given athletics followers something exciting to anticipate.

Could Beijing 2027 become the championship where Noah Lyles transforms an ambitious dream into an unforgettable reality?

Four events, four potential gold medals and the possibility of surpassing one of the greatest sprinting legends of all time. The countdown to Beijing promises to be fascinating.

What began as one of the most entertaining and talked-about stories of the 2026 New York City Marathon has taken an unexpected turn, with Houston-based lawyer Andrea Sager losing her official race result after a viral video showed her smoking marijuana during the event.

The 35-year-old mother of two attracted widespread attention on November 1 when she lined up for the iconic 26.2-mile race wearing a bright pink running vest carrying a humorous personal advertisement: “Andrea, 35, Single. Great Credit. Bad Judgment.” The unusual message quickly made her one of the most recognizable personalities among the thousands of participants, generating plenty of reactions from spectators and social media users.

However, it was another moment captured on camera that eventually landed her in trouble with race organizers. A video circulating online showed Sager accepting a puff of marijuana from a spectator while running along the marathon course, turning what had initially been a lighthearted appearance into a much bigger controversy.

Following the circulation of the footage, New York Road Runners (NYRR), the organization responsible for staging the marathon, removed Sager's finishing time of 5:54 from the official results after determining that she had violated its Code of Conduct. The regulations prohibit smoking, vaping and the use of tobacco or marijuana products in the starting corrals, along the course and within the designated race areas.

Despite the disqualification, Sager was allowed to retain her physical finisher's medal, meaning she still has a memento of completing the demanding journey through New York's five boroughs, even though her official finishing result no longer stands.

Sager has since offered an explanation for her decision, revealing that she was struggling physically as the race progressed. With considerable discomfort in her legs and the marathon becoming increasingly difficult, she said she accepted the offer from a spectator in an attempt to manage the pain and make the remaining miles more bearable.

Interestingly, the controversy has not entirely dampened her enthusiasm for the experience. Rather than retreating from the attention, Sager has embraced the unexpected publicity, revealing that the viral moment has brought considerable interest on social media and dating platforms.

Her distinctive pink running vest has also become a talking point beyond the marathon, with the attention opening up potential opportunities for merchandise and brand partnerships inspired by the memorable message.

Although she initially challenged the decision, Sager has acknowledged that the organizers were enforcing their regulations and appears to be taking the outcome with a sense of humour. She has also indicated that she could return to the marathon distance in the future, suggesting that her New York experience may not be her last.

For Sager, the 2026 New York City Marathon will undoubtedly be remembered for reasons far beyond the challenge of covering 26.2 miles. She arrived at the starting line hoping to enjoy her first marathon and perhaps attract a little attention with her unusual outfit. Instead, she left with a viral story, unexpected publicity and a disqualification that has made her one of the most talked-about recreational runners from this year's event.

Her finishing time may have disappeared from the official results, but her story has certainly found a place in the conversation surrounding this year's marathon.

After all, completing a marathon is an achievement in itself, but Andrea Sager's New York experience came with a twist that few runners could have anticipated!

World mile record holder Josh Kerr has sparked an interesting conversation among runners after questioning the growing popularity of hydration vests, suggesting that many athletes may be carrying more equipment than they actually need for their everyday training sessions.

The British distance-running star shared his thoughts during a Reddit Ask Me Anything session hosted by BBC Sport on Monday, where he responded to questions from fans about training, competition, rivalries and some of the lighter aspects of his life as an elite athlete.

Among the most relatable topics was the increasing use of hydration vests, a piece of equipment that has become increasingly common among recreational runners, particularly those who head out for regular training sessions.

Kerr offered a straightforward perspective, suggesting that runners covering distances of less than 12 miles (approximately 19 kilometres) generally do not need to carry water with them. He believes that some running trends are driven more by marketing than genuine necessity, using hydration vests as an example of equipment that has perhaps become more popular than it needs to be.

He further pointed out that runners training in urban environments can usually find somewhere to purchase a drink if they need one, rather than carrying additional equipment throughout their entire run.

However, his comments were not intended as a universal rule for every athlete. Hydration requirements differ depending on individual needs, weather conditions, training intensity and the distance being covered. Runners tackling longer distances, particularly in hot conditions or on remote trails, may still benefit considerably from carrying their own fluids.

Away from the equipment debate, Kerr also addressed questions about his relationship with Norwegian distance-running superstar Jakob Ingebrigtsen. Keeping his response brief and humorous, the Briton remarked, "I wouldn't say we're buddies!" However, he acknowledged that rivalries are an important part of athletics and can help make the sport more exciting for competitors and spectators alike.

The 2024 Paris Olympic Games also featured prominently in the discussion, particularly the men's 1500m final, where Kerr secured the silver medal in a British record of 3:27.79 behind American Cole Hocker.

Despite narrowly missing out on Olympic gold, Kerr insisted that he had no regrets about how he approached the race, reflecting the confidence and competitive mentality that have helped establish him among the leading middle-distance runners in the world.

The Scottish star also offered fans a glimpse into the demanding training sessions behind his remarkable mile world record, providing insight into the preparation required to compete at the highest level. He additionally touched on the possibility of eventually moving up to the marathon, a prospect that will undoubtedly attract considerable interest given his credentials over shorter distances.

Not every question, however, was about world records, Olympic medals or gruelling workouts. In one particularly amusing moment, Kerr was asked how far he thought he could run on just a single square sausage and a can of Irn-Bru, bringing a distinctly Scottish flavour to the conversation.

The exchange offered a refreshing look at the personality behind one of Britain's biggest athletics stars, showing that even athletes operating at the very highest level have plenty of opinions about everyday running habits.

For recreational runners, Kerr's message about hydration vests is certainly worth considering, although individual circumstances should always determine what equipment is necessary. His broader point was simple: runners should understand their actual training needs rather than automatically following every new trend in the running industry.

Kenyan marathon star John Korir is preparing to chase a remarkable piece of history at the 2026 Valencia Marathon, where victory could make him the first male athlete in more than two decades to successfully defend the prestigious title.

The 30-year-old, who will celebrate his birthday just four days before the December 6 race, returns to Spain with an opportunity to achieve something that has proved exceptionally difficult in the history of the competition. Having conquered the Valencia streets last year in an outstanding 2:02:24, Korir now has his sights firmly set on becoming a two-time consecutive champion.

A successful defence would place Korir in an exclusive group of athletes who have managed to win Valencia's men's marathon twice. The race's historical records identify only three previous multiple winners: Teodoro Pérez, Eduardo Alcaína and Samuel Tangus. Tangus remains the last man to achieve consecutive victories, having triumphed in 2002 and 2003.

Korir's opportunity has become even more promising following the withdrawal of Ethiopian star Yomif Kejelcha, who was ruled out of the December 6 contest because of an injury. Kejelcha had been among the biggest attractions in the anticipated showdown. His absence removes a major challenger and leaves Korir as one of the leading favourites heading into the race.

The Kenyan's recent performances explain why expectations are so high. He has established himself among the world's most formidable marathon runners, collecting major victories in Chicago in 2024, Boston in 2025, Valencia in December 2025 and Boston again in April 2026. His latest Boston triumph was particularly impressive, as he successfully defended his crown in a spectacular course-record time of 2:01:52.

However, Korir is not returning simply to defend his title. He has much bigger ambitions, with reports indicating that he is targeting a historic sub-two-hour performance on Valencia's famously fast course. To prepare for that challenge, the Kenyan has reportedly increased his training volume to between 250 and 270 kilometres per week, demonstrating the scale of preparation behind his ambitions.

Breaking the two-hour barrier would be an extraordinary achievement, particularly on a course where the current men's record stands at 2:01:48, set by Ethiopia's Sisay Lemma in 2023. Korir already knows what it takes to deliver a major performance in Valencia, having produced a commanding victory last year.

Turning 30 just days before the competition, Korir appears to be entering an exciting period of his marathon career. His combination of experience, consistency, confidence and remarkable endurance makes him a serious contender not only for another victory but also for a possible assault on the course record.

For Korir, December 6 represents an opportunity to go beyond another major marathon victory. He could end a 23-year wait for a consecutive men's champion in Valencia, join an exclusive group of multiple winners and potentially deliver one of the fastest marathon performances ever witnessed.

The challenge is now clear: defend his crown, make history and perhaps bring the world closer to another landmark moment in marathon running.