24-hour races are beautifully, brutally simple. One circuit. One day. As many laps as possible.
There is something heroic and universally appealing about pushing your body through a full cycle of the earth’s rotation. Unlike most races over a set distance, this ultra-marathon event is a race over time. 24-hour races enable participants to run alongside each other for the entire race, instead of suffering alone, hours behind the leader. Participants often team up to race relay style, but the gold standard remains the solo discipline.
Completing a 24-hour race requires a combination of physical conditioning, technical preparation, and mental toughness. Getting lapped and lapping others is par for the course, rest is a relative term, and when it comes to calories, it’s cheat day. But this is all part of the thrill.
WHERE IT ALL BEGAN
For most of history, running was a survival tactic. Besides the occasional burst of youthful energy, extreme exertion was generally avoided. In Victorian England however, a few pain-loving pioneers sparked a newfound passion for feats of endurance. The English Channel was swam, competitive walking drew record crowds, and cyclists raced around a velodrome for 6 days straight.
Fast forward to the present day and extreme endurance events are plat du jour. This year, the world record for distance run in 24 hours was broken at a knee-shattering 309.4km (192.3mi). As of July, the cycling record stands at an epic 1026.2km (637.7mi). That’s London to Luxembourg – and back again.
24-hour events are no longer the preserve of the elite. Seasoned athletes race alongside grizzled journeymen. Technophiles obsess over biometric data, while fun runners in bright pink keep up morale. Ultrarunning participation has grown by 345% in the last decade with an estimated 10,000 events hosted each year.  There’s probably one near you.
AM I BUILT FOR ENDURANCE?
If the trim figures of the ultra elite leave you feeling heavy, don’t fret. Research into the factors affecting ultrarunning performance show that size and body fat percentage are not the main predictors of success. These studies concluded that previous race times and training history were most closely associated with ultramarathon performance.
And if you thought you were too old for 24-hour events, consider this. Ultra-endurance events are consistently dominated by runners in their forties with most runners entering their first event in their mid-thirties.
Women are well represented in the sport of ultrarunning. Look no further than Courtney Dauwalter for inspiration. She set the Ultra-Trail du Mont-Blanc course record in 2021, and finished the Moab 240 (yes, it’s 243 miles long) 10 hours ahead of every other competitor – men included.
The take home message is that age, size, and gender are not the most important variables in this discipline. Far and away, the best predictor of performance over 24 hours is the running done before the race.
HOW LONG SHOULD I TRAIN FOR A 24-HOUR RACE?
Most marathon training plans are under 6 months. For 24-hour races however, this is an absolute minimum. Race preparation time depends on your training status. There is no shortcut to race readiness. For those newer to running, 12 months training is recommended. If you are accustomed to half-marathon distance, or running 40 to 50km (25 -30mi) per week, you can progress to ultramarathoning more quickly. Remember that training for a 24-hour event requires acclimatization to new pacing, new strategy, new gear, night-time running, and sleep deprivation – don’t rush.
The average runner takes less than 10 hours to complete a 100km ultramarathon. In a 24-hour event, that’s not even the halfway point. In training for a 24-hour race, the emphasis is on building aerobic capacity at low intensity. One way to do this is to run for time, not distance. When your goal is 3 hours instead of 30km, the focus shifts from covering distance faster to passing time with less effort.
Ultramarathon runners rely on volume rather than intensity during training. However, you should still include high intensity workouts to raise aerobic threshold and improve your capacity for clearing lactic acid.
Tempo runs (70-80% of max heart rate) of increasing duration are a great way to achieve this. Short intervals above 80% of max heart rate are recommended to increase maximal aerobic capacity and strengthen the heart and breathing muscles. Respiratory muscle fatigue is a limiting factor in ultramarathon performance.
THE LONGEST RUN
A question often asked is, “how long should my longest training run be?”. Unlike shorter endurance disciplines, running 70% of the race distance in training is not recommended for 24-hour events. Recovering from such a run will likely disrupt your training schedule and be counterproductive overall. Aim for a run of ~6 hours before your 24-hour race.
It is important to progress at a manageable rate. Increase your training load gradually (5-10% each week) until you are training several hours per week, with at least one long run of a few hours.
Simulate the event with back-to-back runs on tired legs and include specific training for your event. The terrain, elevation profile, and climate of your race determine how you should prepare. Are you training for a mountain trail in Canada or a track event in Australia? Finally, taper your training a month in advance of the event to allow for full recovery.
Pacing in a 24-hour event is a unique challenge. The finish line is a day away, no matter how fast you are. Terrain, elevation, and weather are often changeable. Runners of all abilities are on the same circuit, which interferes further with individual pacing strategy.
No surprise that amateur runners tend to start too fast and change pace too often. Research into 24-hour pacing strategy shows that the best runners start at a lower relative intensity and maintain a steadier pace throughout.
During the race, maintain conversation pace (slow enough to chat). Expect to walk. Walking early and often allows you to rest and eat while still increasing mileage. Scout the course in advance to match your pace to the course profile. Steep, rough or technical sections are often better walked, especially when tired.
In training, run for time not distance. The longest training run before a race was found to be the best predictor of 24-hour performance in recreational runners. The researchers recommended a 60km run before the competition – that’s a 6-hour run at 6-minute pace.
NIGHT RACING AND SLEEP DEPRIVATION
Night racing and sleep deprivation are key features of the 24-hour event. In order to maintain momentum and mileage, sleep is kept to an absolute minimum. Unless you compete in the Arctic Circle, there’s no avoiding hours of darkness.
This requires you to overcome the circadian drowsiness that hits after midnight, in addition to the challenge of low-light conditions and general fatigue. To make matters worse, sleep is often poor in the lead up to the race due to last minute logistics and travel to events. Extreme tiredness can cause confusion, hallucination and delayed reaction time. With most racers opting for just a few minutes’ sleep every few hours, the dangers are real.
To combat the effects of sleep deprivation, consider ‘banking’ sleep in advance of the race. Extending sleep time ahead of competition and daytime napping are popular strategies among ultramarathoners and have been shown to improve alertness and muscular endurance in laboratory conditions.
Extend your sleep by 1 to 2 hours in the weeks before your event and add a daytime nap. Improve your sleep by avoiding screen time and stimulants before bed, as well as sleeping at the same time each day.
In a typical 24-hour ultramarathon, a 70kg racer burns approximately 10,000 cal – four times the normal daily intake. It is impossible to consume this many calories during a race, so to minimize the deficit and optimize energy supply, racers must refuel efficiently.
Compared with shorter endurance events, the pace of 24-hour races allows for plenty of eating on the go. Most calories for the race will come from carbohydrates, often in the form of gels, bars, and drinks. However, for longer ultra-endurance events, fat is increasingly important as an energy source. Have a variety of food available, savoury and sweet to satisfy cravings as they arise.
Carbohydrate intake should be in the range of 30-50g per hour, for fat, around 4g per hour and protein between 5-10g per hour. Pretzels, bagels, biscuits, bananas – even pizza are ideal energy sources. Test your food in training. It is essential that your calories are well tolerated. Peanut butter sandwiches can work just as well as expensive energy bars.
Caffeine and taurine-based drinks can help you stay alert, and boost performance but abstain from stimulants 7 days before the event to enhance the effect on race day. Caffeine should be reserved for later in the race or in the night when stimulation is most needed, and only according to individual tolerance. The latest recommendations are for moderate doses of 50mg per hour. Energy gels containing caffeine are an easy way to manage consumption.
In preparation for the race, a carb-rich diet is essential to prevent a negative energy balance and fuel training. Consuming 10 grams of carbohydrate per kilogram of body weight per day, in the days before the race is recommended to “carbo-load”, though many athletes struggle to consume this amount.
Proper hydration aids digestion, muscular contraction, and cognitive function, which in turn improves performance. In theory, the aim is to replace what you’ve lost due to breathing, sweating, and urinating.
It is often stated that weight loss of just 2% through dehydration can affect health and performance. However, top ultra-endurance athletes frequently lose more than 3% body mass over the course of a race, despite drinking as much as 19 liters.
In practice, experienced athletes trade off a degree of dehydration against hyperhydration (excessive water consumption), to prevent bloating and hyponatremia (low blood salt). Race finishers show better sensitivity to their hydration needs, tending to drink less the day before a race, and more during the race than non-finishers.
The latest recommendation for hydration is therefore to “drink to thirst”. This should be in the range of 150-250ml every 20 minutes depending on your preference and environmental conditions. Hot weather significantly increases fluid requirements, whereas cold weather blunts sensitivity to dehydration.
Be aware that many “sports” drinks do not provide sodium in high enough concentration (recommendations are 500-700mg per liter). Salted snacks and sodium supplements can enhance your intake whilst hypertonic solutions provide a reliable supply of electrolytes and carbohydrates.
Taste and tolerance are important factors, so test your hydration strategy in training to avoid GI upset on race day.
A DAY LIKE NO OTHER
A 24-hour race is a day like no other. The pain and suffering are not to be underestimated but the adrenaline and accomplishment are more than rewarding. With the right approach, you can conquer this unique ultramarathon – and enjoy it too.
There are significant risks associated with 24-hour endurance races. Consult an exercise professional for individual guidance, and balance your training with adequate recovery.