New Guidelines For Fueling

I was sharing with some my patients this past week how I found it amazing that Sebastian Sawe was able to consume 115 grams of carbs an hour in his sub-2 hour marathon. Previous recommended guidelines were between 60-90 grams an hour.

Lo and behold, a patient shared that in the Nice Ironman last year, Casper Stornes (1st place) and Kristian Blummenfelt (3rd) took 120 grams of carbs while running and up to 180 grams on the bike.

Intrigued by what he sent me, I found a recently published review article by Morton et al (2026) which revisits carbohydrate guidelines for endurance athletes. So are the previous fueling recommendations enough?

When training and/ or racing for prolonged periods, carbohydrate intake will spare liver glycogen while maintaining your blood glucose levels. Most importantly, it helps one to sustain higher intensities nearer the end of your race. When everyone else is going faster, you do not want to run out of fuel and slow down.

Fueling is not to just avoid bonking (or hitting the dreaded wall). It is also to delay the shift from using carbohydrates to fat. That shift is not bad, but when you are trying to go fast without carbohydrates it is going to be very difficult. Note that if you are doing Zone 1 or 2 for many hours (like in an ultra marathon) at low intensities, then this shift may not occur.

When one consumes enough carbohydrates during endurance exercise, long ultra race, Ironman event etc, it delays the "crossover point".  This is when carbs stop being the predominant fuel due to glycogen depletion or low carb availability.

You can see from the diagrams above that if no carbs are consumed (0 grams each hour), this happens around 2 hours. With 45-90 grams/ hour, it delays the crossover point by 30-60 minutes. If 120+ grams/ hour of carbs are consumed, there is no crossover point since carbohydrates remain the predominant fuel source while exercising. At least not in cycling studies as the subjects exercised at 90 percent lactate threshold for 3 hours. It may still occur in longer races.

For runners, the review looked at elite male marathoners with personal bests under 2:30 hrs. They completed a 2 hour treadmill protocol close to marathon race intensity while consuming 60, 90 or 120 grams of carbs each hour. 

Those who ingested 120 grams used more of the ingested carbs leading to higher carbohydrate oxidation. They had a roughly 3 percent improvement in running economy compared to 60 grams per hour. There was also greater carbohydrate contribution to total energy expenditure late in the run. Now you know why Sabastion Sawe never slowed down in his sub-2 hour London marathon. 

There's a catch. Gastrointestional (GI) symptoms were also higher at 120 grams/ hour. Nausea, stomach fullness, and cramping were worse in the highest carb intake. More carbs may offer an advantage, but only if your gut can absorb and tolerate them.

The researchers say that runners should use 90 grams of carbs or more per hour as a realistic target for long, hard events. For trained athletes, the range may extend closer to 120 grams per hour. Fueling should be treated like a trainable skill, provided the gut has been trained to handle it.

Runners will find it more challenging compared to cycling since it's much easier to eat on the bike. All the moving, reduced blood flow to the gut, heat stress may lead to higher rates of GI distress.

This is an exciting review for fueling, but do note that most of the research comes from cyling, male athletes and in controlled lab settings. Female athletes are under-represented as well as real world running/ racing conditions.

My takeaway message? For some of you runners, 90-120 grams/ hour will most certainly help your times. Others may benefit from 60-75 grams/ hour. For other runners, it may be just progressing from under-fueling to consistently fueling and getting a personal best no matter how many grams of carbs that may be.

Reference

Morton JP, Fell JM, Gonzalez JT et al (2026). From Metabolism To Medals: Contemporary Perspectives And Revisiting Carbohydrate Guidelines For Fueling Endurance Athletes During Exercise. J Nutrition. 156(5). DOI: 10.1016/j.tjnut.2026.101442

Sub 2 Hour Marathon

Back in 2017, renowned sports scientist Dr Ross Tucker wrote that a sub 2 hour marathon was unlikely to occur for generations. Then Nike introduced the Breaking 2 project which resulted in Eliud Kipchoge running under 2 hours albeit in a paced setting, not in an official race. 

The 2 hour barrier was finally broken last week at the London marathon when winner Sabastian Sawe and runners-up Yomif Kejelcha achieved the breakthrough, the latter running only his first marathon.

The podium

Sawe beat the previous world record by 65 seconds, finishing in 1:59:30 hrs. He ran an amazing negative split, 60:29 for the first half and the next half in 59:01 min. Kejelcha finished 2nd in 1:59:41 hours. The race was so fast that third place finisher Jacob Kiplimo also broke the previous world record (set in 2023) by 7 seconds. He clocked 2:00:28 hrs.

What lead to the breakthrough? Perhaps due to a "perfect storm" or convergence of many of the following factors. 

Sawe's team said he was running in excess of 200 km a week in the 6 weeks leading up to London, with a maximum of 241 km (150 miles). The volume of his training runs is likely an important factor for him to break 2 hours. Not many elite runners can tolerate that sort of volume, especially when most of it is done at low intensity (or Zone 1). High training volume done at relatively low intensity (Zone 1) is associated in faster marathon performances (Muniz-Pumarez et al, 2024).

Sawe's 5 km splits from 30 km onwards were superb. 30-35 km : 13:54 min, 35-40 km : 13:42 min. His final 2.2 km was 5:51 min. His 24th mile was 4:12 min - the fastest single mile ever run in a marathon. As the finishing line beckoned, he was still accelerating. No way he could have done this if he was not fueling well.

Sawe's nutrition was exceptional. I'm not plugging names here, in fact I've not even tried their products, but Sawe is a Maurten athlete. Elite athletes train their gut take up to 120 grams of carbs while competing without GI distress. The previous recommendation was 60 grams per hour previously. Sawe's reported intake was 115 grams an hour. Maurten's research team was with Sawe in Kenya for 32 days across 6 trips between last year and this April to train his gut to absorb that amount. 

Please note that 120 grams of carbs are NOT recommended for the recreational athlete. That is probably why cycling races and marathons are getting faster since there is no depletion in carbohydrate levels.

Sawe also used sodium bicarbonate (also from Maurten) to buffer his lactic acid build up during the race. He took the sodium bicarbonate early since it peaks in the bloodstream  roughly 60-90 minutes after ingestion so the timing of 2 + hours before the race would put peak buffering capacity at the start.

What about his shoes? Adidas says those were the fastest and lightest super shoes ever made. Actually, Adidas had a great day as 4 of the top 5 men were wearing the same Adizero Adios Pro Evo 3. It weighs 97 grams (for men's size 9), 30 percent lighter than its predecessor with a stack height of 39 mm (below the 40 mm limit by World Athletics). 

The Lightstrike Pro foam used is 50 percent lighter than the previous version, along with the carbon plate. Research suggests that the foam and carbon plate can affect the "spring like" bounce of the body as the foot strikes and leaves the ground. The shoes help to store and release energy and acts like the runner is pushing off a springboard so less energy is needed for the run.

London is considered a relatively fast course (though not as fast as Berlin) and the weather conditions was between 13-17 degrees Celsius, close to ideal.

There you have it, exceptional athlete physiology, high mileage training without injury, efficient biomechanics, super shoes , optimized fueling and favorable conditions. The recipe for success for running marathons.

Reference

Muniz-Pumares D, Hunter B, Meyler S et al (2025). The Training Intensity Distribution Of Marathon Runnersd Across Performance Levels. Sports Med. 55: 1023-1035. DOI: 10.1007/s40279-024-02137-7

Flat Feet And Overpronation

On Friday night, a patient sent me a message with pictures (above) regarding her daughter's flat feet. She was worried that it was affecting her knee, hip and lower back. Subsequently, she brought her daughter into the clinic to see me yesterday. 

Her daughter has increased her running and training more recently for her National School Games bowling competition in the first week of May. She just started having mild pain in her left foot on Friday. Because of the pain, my patient was worried about her daughter's "over" pronation. 

The readers following this blog will recall that I have written before that children from 11 months to 19 years old with flat feet are perfectly fine and do not need orthotics. You can view the Cochrane review here. 

"Over" pronation is a word that is often used by many healthcare professionals to tell their patients that it is a cause of their foot pain. However EVERYONE has to pronate when they walk or run. When you take a step forward while walking, you often land on your heels. After heel strike, the whole foot lands on the ground and this is when your foot pronates. Now imagine having insoles or orthotics to block that movement. That is what happens when you try to limit pronation.

This mechanism is very necessary otherwise no load will be distributed up the leg. In fact, it often does not cause issues in runners. And yet, patients are somehow steered and asked to avoid, limit or alter pronation at all cost.

Of course there may be occasions when you have pain in your foot or arch, and healthcare professionals may have to take the load off the area temporarily to alleviate the structures that have been irritated.

The following study by Nielsen et al (2013) published in the British Journal of Sports Medicine investigated whether newbie runners with different foot positions had more or less injuries by wearing a neutral shoe regardless of their foot type or mechanics.

The 927 newbie runners with different pronation types were followed for a period of 12 months. All the runners received the same pair of neutral running shoes regardless of whether they had neutral foot pronation or not.  

The runners accumulated a total of 163, 401 km that year. 252 runners suffered a running injury in that period. In addition, the number of injuries per 1,000 km of running was significantly lower among runners who under or over pronate than among those with neutral foot pronation.

The authors found "no risk that overpronation or underpronation can lead to running injuries through using neutral shoes for this special group of healthy beginners." The authors "compared runners with neutral foot pronation with the runners who pronate to varying degrees, and our findings suggest that overpronating runners do not have a higher risk of injury than anyone else."

The authors thought their findings were 'controversial', since it has been assumed for many years that one would risk injuries to run in shoes without the necessary support if you under or over pronate.

The study also found that the risk of injury was the same for all their runners after the first 250 km, irrespective of their pronation type. 

Note that the study did not look at what can happen if runners run in a pair of non neutral shoes nor did they investigate what runners should consider with respect to pronation and choice of shoe if they are already injured.

So as I explained to my patient and her daughter whose foot pain has gone away, that pronation or more accurately, overpronation is not to be feared.

References

Nielsen RO, Buist I, Parner T et al (2013). Foot Pronation Is Not Associated With Increased Injury Risk In Novice Runners Wearing A Neutral Shoe: A 1-Year Prospective Cohort Study. BJSM. DOI: 1136/bjsports-2013-092202.

How I Train My Breathing Muscles

My respiratory muscle trainer

Over the Easter weekend, my family and I were away in Lake Toba. Since I would be missing my regular Saturday ride, I brought along my inspiratory muscle trainer, so I could at least train my inspiratory muscles while away. I had previously written about training your breathing muscles.

I do not run with mine, just sit and breathe with it

There are different ways to train your breathing muscles. The 2 most common techniques are voluntary isocapnic hyperpnoea (VIH) and inspiratory pressure threshold loading (IPTL).

VIH involves breathing at high volumes and rates so it is similar to intense exercise while maintaining carbon dioxide at stable levels to avoid dizziness. It is primarily done using specialized devices like the Breathe Way Better device which allows you to rebreathe exhaled carbon dioxide from a bag. This creates a close loop to keep blood gas levels balanced when allowing you to strengthen your inspiratory muscles.

IPTL strengthens the breathing muscles using a device with a calibrated, spring-loaded valve like the Power Lung or the Power Breathe that requires a consistent force to open. Users breathe in forcefully through the mouth against this resistance. It creates a "threshold" that must be overcomed to be able to breathe in. That was the device that I brought along.

Where did I get this idea from? Thanks to Kowalski and colleagues (2023) who investigated 16 well trained triathletes (7 females, 9 males) for  6 weeks using the VIH or IPTL program with progressive overload. 

Both subjective and physiological responses were monitored across sessions. Blood markers, muscle oxygenation and cardiac indices were all measured before, during and after the training sessions to track adaptation and load.

The results show that both VIH and IPTL training increased physiological load. Blood gas analysis showed larger post respiratory muscle training differences in females compared to males. VIH induced smaller changes in blood gasometry compared to IPTL.

VIH produced higher subjective training load and perceived exertion compared to IPTL. IPTL caused greater metabolic stress, altering acid-base balance, elevated lactate and caused dizziness and headache.

The authors concluded that respiratory muscle training added measurable mental and physiological load in well trained triathletes. Usage of such training should be individualized depending on method and training context since this study suggests that the load (30 breaths twice a day) is significant enough to add to training load.

Even though the protocol is short and easy to fit into a training regime, my suggestion is to take it slow and use lower loads and progression to complement your regular training. 

Did it help my following Saturday ride after my Easter trip? I think it did. I fared better than I expected.

References

Kowalski T, Kasiak PS, Rebis K et al (2023). Respiratory Muscle Training Induces Additional Stress And Training Load In Well-Trained Triathletes - Randomized Controlled Trial. Frontiers in Physiology. 14: 1264265. DOI: 10.3389/fphys.2023.1264265

Farewell Physio Solutions

Thank you to our patients for supporting us through the years since we opened in 2007.

We bid goodbye to our first clinic, Physio Solutions, after 19 years at Singapore Shopping Centre. This space provided us with the opportunity to grow our patient base and train young physiotherapists. 

It gave us the space to learn how to manage a small clinic, allowing us to open a bigger second clinic in Amoy Street, 2 years later. It has been a great run and we could not have asked for more.

Will miss this room with a view

This year, when our lease came up for renewal, Gino and I decided to streamline and simplify now that we are in our 50s. We will both see our patients at our clinic in Holland Village, Sports Solutions, together with our team of physiotherapists.

Here’s to a new season of life!

To start with, it has been a nice change to be able to walk to work since April!

With the receptionists from the dental clinic next door

Being In Nature Helps

View of Lake Toba

I hope you are enjoying your Easter long weekend as you read this. My family and I are away this weekend in Lake Toba, in Medan, Indonesia

Last week, we discussed how being fit may protect us from depression and dementia. This past week I came across another article that shows how a 90 minute walk in nature also helps.

Pictures taken by walkers comparing their walks

In that study, participants who went on a 90 minute walk in nature reported lower levels of rumination. Rumination is the subjective, conscious recognition of dwelling on negative feelings, distress and their causes. It often links stress to depression and anxiety. Rumination is a know risk for mental illness.

These participants also showed reduced neural activity in an area of the brain linked to risk for mental illness compared to those who walked through an urban environment.

These results suggest that accessible areas in nature may be vital for mental health in our repidly urbanizing society.

Especially since more than 50 percent of  people live in urban areas. It is estimated that by 2050, this proportion will be 70 percent.

Not a cure-all to be in nature, but a good reminder that environment can shape mental well being. 

Reference

Bratman GN, Hamilton JP and Gross JJ (2015). Nature Experience Reduces Rumination And Subgenual Prefontal Cortex Activation. PNAS. 112(28): 8567-8572. DOI:10.1073/pnas.1510459112

That's our >90 min nature walk

Does Better Fitness Protect Us From Dementia And Depression?

I'm not a mental health expert. I only know that I always feel better after I run, cycle or do any other form of exercise. Especially if I've been particularly stressed about something or everything.

We know for sure that having good cardiorespiratory fitness is a strong indicator of overall physical  health. However, is someone with good cardiorespiratory fitness less likely to have mental health disorders or dementia later in life?

A newly published systematic review and meta-analysis provides new updates on this link across all age groups in their study (Diaz-Goni et al, 2026). 22 studies (out of 27 chosen) with 4,007,638 participants were studied in that review. 

The participants were between 18 and 64 years old, who had fitness measured at baseline and followed for 4 to 29 years. Different methods were used for measuring fitness. Some studies used VO2 max, others used indirect or submaximal exercise tests while others measured peak workload and exercise duration. Note that this paper talks about cardiorespiratory fitness and NOT about VO2 max values.

Higher cardiorespiratory fitness was associated with substantially lower future risk of depression, psychotic disorders and dementia. However it did not show to clearly help with anxiety.

Each 3.5 mL/kg/ min (or 1 MET) increase in cardiorespiratory fitness was associated with a 5 percent lower risk of depression and 19 percent lower risk of dementia.

Overall, those with higher cardiorespiratory fitness had a 36 percent lower risk of depression, 39 percent lower risk of dementia and 29 percent lower risk of psychotic disorders compared to those with lower fitness.

The authors discussed a few potential mechanisms that may explain why higher cardiorespiratory fitness helps mental or neurocognitive disorders.

From a physiological perspective, improved brain blood flow, vascular function induces structural, cellular and molecular adaptations to enhance neuroplasticity which then support cognitive and emotional regulation.

Exercise and higher cardiorespiratory fitness has been shown to help maintain the size/ volume of the hippocampus. The role of the hippocampus is linked to emotion regulation, memory and cognitive resilience. Atrophy of the hippocampus has been consistently linked to mental and cognitive disorders.

Mental health disorders and neurodegeneration are definitely complex and multifactorial. Please note that the authors also did not just conclude that "exercise is the answer". They concluded that higher cardiorespiratory fitness appears to be associated with a lower risk of several mental and neurocognitive disorders and cardiorespiratory fitness may be a useful marker to sort out groups at risk.

This is also interesting to note. Because only 1 or 2 studies were available, the authors were not able to study them as a group. Those individual studies suggested that higher fitness may be associated with lower risk of bipolar related disorders, dissociative, obsessive-compulsive and stressor-related disorders, sleep apnea as well as anxiety and ADHD in children. Depression in girls also appeared lower with higher fitness.

If the fitness influencers do pick up on this topic, I hope they do not simplify it by making it as easy as doing "some exercise or sports". 

So taken at face value, higher cardiorespiratory fitness seems to lower risk across a wide range of psychiatric and neurocognitive disorders. Do note that genetic predisposition, chronic pain, social support, smoking and diet are definitely confounding factors.

The evidence does continue to add up showing that higher cardiorespiratory fitness helps with physical disease and premature death, but also with better mental health, lower dementia risk and other mental disorders. 

Reference

Diaz-Goni V, Lopez-Gil JF, Rodriguez-Gutierrez E et al (2026). Cardiorespiratory Fitness And Risk Of Mental Disorders And Dementia: A Systematic Review And Meta-Analysis. Nat Mental Health. DOI: 10.1038/s44220-026-00599-4