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Hemoglobin is measured in every blood panel, a major determinant of athletic potential staring us right in the face.

Hemoglobin is a protein in red blood cells that carries oxygen to working muscles. It's a load-bearing pillar of athletic performance and aerobic development, influenced by genetics, iron levels, training history, altitude, and stress. Hemoglobin is so important that endurance sports have faced existential crises from athletes trying to hijack their physiologies through illegal, immoral performance-enhancing drugs like EPO, which stimulates red blood cell production and increases hemoglobin levels. 

A disturbing 2013 study in the PLOS One journal found that 4 weeks of EPO injections increased hemoglobin mass by 19.7%, which corresponded to a 6% improvement in 3k time trials with no training changes. That study was funded by the World Anti-Doping Association, which seems similar to the DARE program conducting a study on whether or not heroin feels good. Interestingly, that study also tried to optimize for iron levels to improve hemoglobin mass increases, having athletes take 100 mg of elemental iron a day (550% of the recommended daily value). Unethical, arguably evil use of EPO and blood doping has risked ruining Olympic endurance sports over the last 30 years, and it all gets back to that simple biomarker. Increased hemoglobin mass improves oxygen transport during exercise and thus has a profound impact on performance.

Cheating to raise hemoglobin mass is both vile and dangerous. But what if I told you that there are healthy, legal interventions that can improve hemoglobin mass? You can tell they are healthy because they often correspond with reduced stress and improved cardiovascular function-think optimizing iron intake, balancing stress, and living at altitude. You can tell they are legal because the interventions work over longer time horizons and only budge hemoglobin mass by a couple percent at most. It's the difference between feeling good after eating a serving of dark chocolate versus feeling good after snorting a bunch of cocaine. 

New Study on Heat Exposure and Hemoglobin Mass

A 2022 study in the Scandinavian Journal of Medicine and Science in Sports asked a fascinating question: how does heat training via heat suits affect hemoglobin mass in elite athletes? To evaluate the question, the study split 25 elite cross-country skiers into a heat group and a control group that were matched for intensity and duration of training. We're not just talking normal athletes, but national and international competitors at the pointy end of human performance. So any changes in hematological variables would be coming on top of relatively optimized physiologies.

Participants in both groups completed normal training in the AM. In the PM, the heat group did 50 minutes of low-intensity indoor cycling on a stationary bike 5 times a week for the 5-week intervention. But there was a very hot twist. They were wearing a "wool layer on both the upper and lower body, a wool hat, nylon rain jacket, down jacket, and nylon pants with poor evaporative capacity." While they followed the study instructions well, they fully ignored Nelly's instructions, because it got hot in there and they put on all their clothes. We need a follow-up study to test whether they do, in fact, want scrubs.

Despite the added double sessions in the heat, there was no difference between the groups in training duration or intensity across the 5 weeks. Now is the time when we take a step back to hypothesize what we think happens next. The participants' baseline attributes are relevant to your guesses. The heat group had a starting point hemoglobin of 16.1 g/dl and hematocrit of 45.7%, already very high (likely due to some combination of training and genetics). For comparison, in that dastardly EPO study, the end point for hemoglobin levels was 15.2 g/dl even after the 20% increase from undergoing the Armstrong protocol. Moving a pebble with a bulldozer is one thing. But this study was looking at moving a boulder with a finger flick. Could a flick of heat exposure with low-intensity training move that boulder?

The answer: a resounding yes. The boulder didn't move far, but it left an unmistakable trail, kind of like one of those mysterious moving rocks in Death Valley. And any movement of hematological variables through healthy means at this elite level of performance is a BIG FREAKING DEAL. 

Relative to the control group, the heat group's hematocrit increased by 1.58% and hemoglobin mass increased by 30 grams. While there was no change in the performance metrics tested, those blood changes should have beneficial impacts on performance and recovery over longer time horizons. 

So, Should I Just Hit the Sauna?

Here is where things get complicated, interesting, and frankly, a bit annoying. A 1997 study in the International Journal of Sports Medicine found no hemoglobin mass changes with 4 weeks of training in hot environments between 19 C and 32 C, with numerous studies over the years showing small or negligible changes. That is contrasted by a 2022 study in Medicine and Science in Sports and Exercise that found 2.4-2.6% increases in hemoglobin mass from training in a heat suit or heat chamber (see also this 2020 study in the journal Experimental Physiology and this 2019 study in Frontiers of Physiology showing hemoglobin mass increases from heat acclimation protocols). And now is where we have to start questioning the exact mechanism at play, which will help determine how you put these findings into practice.

One theory is that with heat exposure, the body increases plasma volume (the liquid content in the blood), reducing hematocrit (the percentage of red blood cells within a blood sample) through dilution. As the kidneys sense an offset, the body increases natural EPO production to raise hematocrit levels to baseline, but with a higher denominator from the increased plasma volume, thus increasing the numerator: red blood cells and total hemoglobin mass. In that formulation, even after the plasma volume goes down later, the body will be left with more hemoglobin mass to play with.

If the driver is just the plasma volume-hematocrit-hemoglobin mass pathway (for more, the "critmeter" theory is outlined in this 2003 conference paper), it shouldn't take heat suits or heat chambers to spur the adaptations. We should have seen them in the 1997 study, or other studies finding increased plasma volume from training interventions. Maybe it doesn't have to just be kinda hot, it needs to be REALLY hot. As the authors of the main 2022 study, we are looking at say: "The rate of EPO synthesis is mainly regulated by the hypoxiainducible factor (HIF) system, which, however, also has been shown to stabilize with increased heat shock protein expression." (Check out this 2005 research article in Physiological Genomics to go deep on the subject.) Heat shock proteins that incite the HIF system may require higher temperatures than normal training in warm ambient air.

Context and Implications of Heat Training

And that's just the tip of the iceberg (the hotberg?). A recent study on the topic of natural EPO synthesis made me concerned, and it has nothing to do with heat at all. Published online in November 2022 in the American Journal of Physiology, Endocrinology, and Metabolism, it found that post-exercise ingestion of exogenous ketones increased natural EPO production by 20% over a control group. While the mechanism is uncertain, it's possible that post-exercise ketones incite the HIF system, which may be part of the reason why it's reported that more than 60% of the Tour de France peloton takes them. 

I'm bringing up that preliminary study on ketones to illustrate why I'm such a proponent of heat for athletes probing the margins of performance physiology: studies seem to indicate that it's a natural, healthy way to increase hemoglobin mass and improve performance without probing the gray areas of what else incites the HIF system. Heat exposure has been practiced by some cultures for centuries, with plenty of positive impacts that have nothing to do with endurance performance (though based on the recent success of sauna-loving Norwegians, maybe there's a connection there too). 

There are tons of unanswered questions that will be addressed by future studies. How do these adaptations unfold over longer time horizons, as plasma volume stabilizes? Will it work with passive heat exposure, like the sauna or a hot bath? Could it be counterproductive in athletes with limitations on hemoglobin production, like those with low iron stores or naturally low genetic setpoints? Would it be less effective at altitude? Could there be hormonal impacts that reduce the efficacy over time, or prevent it from working in female athletes at all? That last question is the biggest, since all of the studies I have seen do not include female participants, likely because the menstrual cycle causes blood volume fluctuations beyond those seen from the interventions. 

Conclusion: So, How Much Heat Training Do I Need?

The longer I coach, the more I support year-round heat exposure because these study findings seem to be backed up in the training data for athletes Megan and I coach, even for performance in temperate conditions. I think there might also be a health benefit in winter, with increased blood volume assisting with healing and recovery at a time when blood volume can naturally contract by more than 10%. 

My very loose suggestion: talk to a doctor. After the doctor approves, consider a background heat stimulus year-round if you enjoy it (possibly conducted in a manner that can spur heat shock proteins, though always being safe). Examples include a sauna, hot bath, hot tub, or heat suit. Don't overdo it-heat is a major stress, and it can be dangerous. Please be careful.

I personally like to aim for 2 heat exposures a week, with one on my rest day and the other one whenever I have time, usually consisting of 15-25 minutes in the sauna or hot bath (getting out whenever my heart rate gets above 120, and being extra careful in hot baths since I seem more sensitive to them). A typical week when not doing specific heat training for a hot event might look like this:

The jury is still out on whether the hemoglobin mass increases from heat training seen in studies will apply to everyone (or anyone in the real world who isn't doing 50-minute bike sessions in their entire wardrobe). So most of all, consider this intervention if it's FUN, a way to add a bit more sweat to your day, and only if it's approved by your doctor, lawyer, family, and life insurance salesperson. 

There are some cool adaptations at the limits of our physiology. And the coolest part about heat: you may be able to explore some of those adaptations while soft pedaling in a couple layers of clothes, sitting on a wood bench, or taking a relaxing bath. 

 

 

Long before he became the fastest man in history, before the Olympic gold medals, world records, and global superstardom, Usain Bolt was simply a gifted teenager with extraordinary speed and limitless potential. In 2002, on the track at Kingston's National Stadium in Jamaica, the world witnessed the first chapter of a story that would forever change athletics.

At just 15 years old, Bolt lined up for the men's 200 metres at the World Junior Championships with the weight of expectation resting on young shoulders. Competing before a passionate home crowd, the Jamaican prodigy produced a performance that instantly captivated the athletics world. Crossing the finish line in 20.61 seconds, he became the youngest athlete ever to win the men's 200m title at the championships.

It was far more than a gold medal. It was the moment the world realised that a once-in-a-generation talent had arrived.

Bolt's victory in Kingston marked the beginning of one of the greatest careers in sporting history. Over the years that followed, he rewrote the record books, dominated the Olympic Games and World Championships, and transformed sprinting into a global spectacle through his breathtaking speed, infectious personality, and unrivalled confidence. His legacy continues to inspire young athletes across the globe, many of whom dream of following the same path he once began as a teenager.

This week, that dream comes alive once again as the World Athletics U20 Championships take centre stage at the iconic Hayward Field in Eugene, Oregon. The venue has already witnessed the birth of future superstars. In 2014, it was where Britain's Dina Asher-Smith and Uganda's Joshua Cheptegei captured their first global titles, launching careers that would later produce world championships, Olympic medals, and lasting legacies in athletics.

Twelve years later, another generation arrives in Eugene hoping to create its own defining moment.

Among the brightest young talents is Great Britain's Jake Odey-Jordan, the 200m bronze medallist from Lima who now owns the European U20 100m record after an astonishing 10.01-second performance. He enters the championships eager to build on his growing reputation as one of Europe's most exciting young sprinters.

The United States will look to Tate Taylor, who has already made history as the first American high school athlete to break the 20-second barrier for the 200 metres. Fresh from a Diamond League victory in a sensational 19.75 seconds, he arrives in Eugene carrying the momentum of one of the most remarkable junior seasons ever recorded.

Jamaica, the nation that introduced the world to Usain Bolt, will once again have high hopes through Shanoya Douglas. The talented sprinter has established herself as one of the championship's leading contenders after producing lifetime bests of 10.98 seconds for the 100m and 22.11 for the 200m this season.

History has repeatedly shown that the World U20 Championships are far more than a junior competition. They are often the first chapter in the careers of future Olympic champions, world record holders, and global icons. Every generation arrives with ambitious dreams, but only a select few leave having announced themselves to the world.

No one can say with certainty whether the next Usain Bolt will emerge this week. Greatness cannot be predicted, and legends are never manufactured. Yet every legendary career begins with a single breakthrough performance.

For Bolt, that defining moment came in Kingston in 2002.

Now, under the famous lights of Hayward Field, another group of gifted teenagers stands ready to chase history. Somewhere among them could be the next athlete whose name will inspire the world for years to come.

"An athlete cannot run with money in his pockets. He must run with hope in his heart and dreams in his head." More than seventy years after those words were spoken, they remain among the most powerful messages ever shared in distance running. They are often quoted as simple motivation, but behind them lies a remarkable story of sacrifice, courage, conviction, and an unwavering belief that true greatness is never measured by financial reward.

Few athletes have left a legacy as enduring as Emil Zátopek. Known around the world as "The Czech Locomotive" for his relentless determination and unmistakable running style, he redefined what was possible in endurance racing. His legendary performance at the 1952 Olympic Games in Helsinki still ranks among the greatest achievements in athletics history. In the space of just nine days, he captured Olympic gold in the 5,000 meters, the 10,000 meters, and, incredibly, the marathon—a race he had never attempted before.

Yet the world in which Zátopek competed was vastly different from today's professional athletics landscape. During the 1950s, elite sport officially operated under strict amateur rules. Olympic athletes were forbidden from accepting prize money or earning a living directly from competition, although unofficial financial arrangements existed in many sports. Zátopek himself never raced for appearance fees or lucrative prize purses. Instead, he served as an officer in the Czechoslovak People's Army, receiving a military salary while representing his country. Running brought him glory, but not personal wealth.

It was within that environment that his famous words carried genuine meaning. For Zátopek, success was never driven by the promise of money. He believed the greatest performances were fueled by hope, ambition, discipline, and the courage to pursue dreams that seemed impossible. Those qualities, rather than financial incentives, formed the foundation of lasting excellence.

With the benefit of history, his words carry even greater significance. In 1968, during the Prague Spring, Zátopek openly supported democratic reforms in Czechoslovakia. When the movement was crushed, he paid a heavy personal price for standing by his principles. He was stripped of his military rank, removed from public life, and forced into years of manual labor. The man who had once stood proudly atop the Olympic podium found himself performing physically demanding jobs, far removed from the stadiums where he had inspired millions.

His story reminds us that the values he expressed were not empty words crafted for public admiration. He lived by them, even when doing so came at enormous personal cost. His belief that hope and conviction mattered more than material rewards became evident not only in the races he won, but also in the hardships he endured with remarkable dignity.

Distance running has changed dramatically since Zátopek's era. Today's elite athletes compete in a fully professional sport where prize money, sponsorship contracts, appearance fees, and endorsement deals can be worth millions. Success on the track and roads now offers opportunities that were unimaginable during the age of amateur competition. Professionalism has transformed the sport, allowing athletes to train full-time, access world-class coaching and sports science, and build financially secure careers.

Yet despite these changes, the essence of Zátopek's message has never lost its relevance.

Every elite runner naturally hopes to earn a good living from years of dedication and sacrifice. There is nothing wrong with financial success, and the rewards available today have elevated the standard of competition across the world. But history consistently shows that money alone is rarely enough to sustain greatness. The athletes whose careers endure the longest are often those driven by an inner passion to improve, to test their limits, and to chase excellence for its own sake. Financial rewards become the result of that commitment, not the reason for it.

When competition is motivated solely by wealth, its deeper purpose can fade. But when an athlete races with genuine belief, relentless determination, and an unwavering dream, extraordinary performances often follow naturally.

That is why Emil Zátopek's words continue to resonate across generations. His legacy extends far beyond Olympic medals and world records. It lives in every runner who laces up their shoes with a goal that cannot be measured in dollars, every athlete who refuses to surrender when the race becomes painful, and every competitor who understands that the greatest victories begin long before the finish line.

The economics of distance running may have evolved beyond recognition, but the heart of the sport remains unchanged. Every athlete still arrives at the starting line carrying something far more valuable than money—hope in their heart and dreams in their head. Those invisible qualities have always been, and will always remain, the true fuel of greatness.

Winning a major championship is never just about crossing the finish line first. Behind every gold medal lies a carefully crafted race plan, and Josh Kerr's unforgettable Commonwealth Games triumph in Glasgow was a perfect example of tactical brilliance meeting extraordinary finishing speed.

While the final time of 3:54.12 for the mile will be remembered as the official result, the split times reveal a much deeper story—one of patience, precision, and devastating acceleration when it mattered most.

Kerr resisted any temptation to force the pace from the gun. Instead, he settled into a controlled rhythm, allowing the opening stages to unfold naturally. His first four 100-metre segments—14.9, 15.1, 15.3 and 15.1 seconds—brought him through 400 metres in 60.4 seconds, a measured opening that conserved valuable energy while keeping him firmly in contention.

The second lap remained equally composed. Passing 500 metres in 15.3 seconds before recording splits of 15.7, 16.2 and 15.4, Kerr reached 800 metres in 2:03.0. The pace had eased, but that was exactly where the Scottish star wanted to be. Rather than chasing early speed, he was setting the stage for a decisive finish.

Everything changed after halfway.

Kerr gradually increased the tempo with smooth, controlled acceleration. His 900-metre and 1,000-metre splits of 15.2 and 14.9 seconds signalled that the race was beginning to stretch. He then surged through 1,100 metres in 14.3 seconds before covering the next 100 metres in just 13.4 seconds to reach 1,200 metres in 3:00.8.

From there, the home crowd witnessed championship running at its finest.

Instead of fading, Kerr became even stronger. He reeled off three consecutive 100-metre splits of 13.4, 13.4 and 12.8 seconds, dismantling the field with every stride. His final 100 metres were covered in a stunning 12.5 seconds, sealing an emphatic victory and sending the Glasgow crowd into celebration.

The progression of his race was remarkable. After opening with relaxed 15-second splits, Kerr transformed the closing stages into a demonstration of world-class speed endurance. His ability to accelerate continuously over the final 600 metres highlighted not only exceptional fitness but also supreme confidence in his race plan.

Championship middle-distance racing is rarely about producing the fastest possible time from the start. More often, it rewards athletes who understand when to conserve energy and when to unleash everything they have left. Kerr executed that philosophy to perfection.

His split chart paints the picture of a runner who never panicked, never wasted effort, and saved his greatest weapon for the closing stages. It was a textbook display of patience followed by relentless aggression—a combination that turned a tactical race into a memorable Commonwealth gold medal performance.

For aspiring middle-distance runners, Kerr's Glasgow masterpiece offers an important lesson: the strongest finish often belongs not to the athlete who runs hardest from the gun, but to the one who knows exactly when to make their move. On home soil, Josh Kerr timed that move to perfection, producing a performance that will stand as one of the defining moments of the championships.

At just nine years old, Oliver Smith has achieved something extraordinary—not by chasing records or medals, but by proving that determination, compassion, and consistency can create a life-changing impact.

Hailing from Wombwell, on the outskirts of Barnsley, Oliver set himself a remarkable challenge at the beginning of the year. Rather than attempting a single marathon, he decided to complete the equivalent distance of nine marathons over several months. From January 1 to April 26, the young runner covered an incredible 380 kilometres, breaking the distance into manageable daily runs suitable for a child his age.

His routine was built on dedication. Saturdays were reserved for parkrun events, Sundays for junior parkrun, while the remaining kilometres were steadily accumulated throughout the week. Averaging approximately 3.3 kilometres each day, Oliver never lost sight of the goal that inspired every step.

The challenge carried deep personal meaning. Last summer, Oliver's father, Tom Smith, suffered a devastating health setback after losing most of the vision in one eye. Medical examinations revealed a 4-centimetre meningioma wrapped around his optic nerve, leading to a complex 12-hour operation at the Royal Hallamshire Hospital in Sheffield.

Throughout the family's difficult journey, The Brain Tumour Charity provided invaluable guidance, support, and reassurance. Grateful for the help his family received, Oliver decided he wanted to give back in the most meaningful way he could. He launched a fundraising campaign with an initial goal of raising £2,000 to support others facing similar challenges.

What followed exceeded everyone's expectations.

Oliver brought his incredible fundraising challenge to a memorable conclusion at the Mini London Marathon, finishing on the very same day his mother, Hannah Smith, completed her first-ever London Marathon. It was a fitting family celebration of courage, resilience, and perseverance.

By the time Oliver crossed the finish line, donations had soared beyond £16,500—more than eight times his original target. His remarkable achievement captured the hearts of supporters, demonstrating how one young boy's determination could unite an entire community behind an important cause.

For Oliver, however, the journey is far from over. Inspired by the overwhelming support and the difference his efforts have made, he has already begun working toward his next fundraising challenge.

His story serves as a powerful reminder that age is no barrier to making a meaningful difference. Sometimes, the greatest acts of courage are measured not by speed or distance, but by the willingness to take one small step after another for the benefit of others.

Oliver Smith's inspiring journey is more than a fundraising success—it is a testament to the strength of family, the power of kindness, and the extraordinary impact that can begin with the simplest decision to help.

Sometimes the smallest opportunity creates the greatest triumph, and Jamaica's Navasky Anderson proved exactly that with a stunning performance to capture the men's 800m title at the 2026 Commonwealth Games in Glasgow.

Less than 24 hours after scraping into the final by the slimmest of margins, Anderson produced the race of his life, surging to victory in 1:45.33 to complete one of the most remarkable comeback stories of the championships. His gold medal was not only a reward for exceptional talent but also for courage, determination, and unwavering belief when everything was on the line.

The journey to the top nearly ended in the semifinals. Locked in an intense battle with England's Max Burgin for the final qualification place, Anderson threw himself across the finish line in a dramatic dive, stopping the clock at 1:45.38. That desperate effort earned him the last available place in the final as the fastest non-automatic qualifier, keeping his Commonwealth dream alive by the narrowest of margins.

With another chance in his hands, the Jamaican made sure it counted.

In a fiercely contested final, Anderson displayed outstanding tactical awareness and patience throughout the opening stages before unleashing a devastating finishing kick down the home straight. His perfectly timed acceleration left the rest of the field with no answer as he crossed the finish line first, securing a memorable Commonwealth crown and one of Jamaica's standout victories of the Games.

Australia's Luke Boyes delivered an impressive performance to claim the silver medal in 1:45.93, while Kenya's Wyclife Kinyamal battled strongly to take bronze in 1:46.12 after another highly competitive championship race.

Anderson's unforgettable triumph will be remembered as one of the defining moments of Glasgow 2026—a powerful reminder that championships are not always won by the fastest qualifier, but often by the athlete who refuses to surrender. From a fearless dive that kept his hopes alive to a brilliant gold-medal performance less than a day later, the Jamaican wrote one of the most inspiring chapters of these Commonwealth Games.

Men's 800m Final Results

1. Navasky Anderson (Jamaica) — 1:45.33

2. Luke Boyes (Australia) — 1:45.93

3. Wyclife Kinyamal (Kenya) — 1:46.12

Navasky Anderson arrived in the final as the last man to qualify, but he left Glasgow as the Commonwealth champion—a remarkable transformation that perfectly captures the unpredictable beauty of championship athletics.