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I'm training for the London Marathon — here's how sleep makes you a better runner
In a world of sports massages, fancy recovery tech, performance-enhancing supplements, sleep is an undervalued recovery tool among many marathon runners.
I’m a sleep writer training for the London Marathon 2025, and in pursuit of running my best, I’ve been prioritizing and optimizing my sleep.
This has involved sleeping on one of the best smart mattresses of the year, testing various sleep gadgets and, most importantly, sticking to a regular sleep schedule.
This Sleep Awareness Week, I’ve spoken to former British champion runner, lecturer and Coopah head coach, James Thie, and UK Sports Institute performance innovation consultant and sleep and circadian scientist, Dr Luke Gupta, to find out exactly how important sleep is for endurance athletes.
Learning from the greats
When you imagine someone training for a marathon, you likely think of them pounding the pavements early in the morning, sporting a trendy running vest and trainers, getting their run ticked off before work.
What you might not think about is them curled up in bed by 9pm the night before a long run. But in fact, a lot of time during a successful marathon training block is spent sleeping.
James Thie is a head coach at the official training platform for the London Marathon, Coopah, and senior lecturer in Sports Coaching and Performance at Cardiff Metropolitan University. He was once a finalist at World, European and Commonwealth championships and sub 4 minute miler.
Paula Radcliffe slept nine to 10 hours a night and another couple of hours in the afternoon during training.
While training to break two hours in the marathon, Eliud Kipchoge slept 8 hours each night and took a two-hour nap during the day. Granted I will not be running close to a two hour marathon.
I’ll be happy to run anything under four hours. But taking leaves out of the professionals’ books does no harm and one thing is clear — you cannot underestimate the power of sleep in boosting running performance.
“Our bodies are the smartest bit of technology, equipment and kit that we're ever going to get"
James Thie
More and more people are toeing the start lines of marathons worldwide. London Marathon 2025 had a record breaking 840,318 people apply for the public ballot and Strava’s Year in Sport 2024 Report found 43% of the app’s users said they want to conquer a big race or event in 2025.
With this comes a greater need to understand the importance of rest, recovery and, crucially, sleep when taking on these intense physical challenges.
Good sleep is essential when I'm training for a marathon — here's why
Most marathon training blocks last between 12 and 18 weeks, which is a long time to be pushing your body through its paces. Therefore, rest, recovery and, crucially, sleep is extremely important to any endurance runner, especially if you want to reach peak performance.
Sleep is one of the most underrated forms of natural recovery
“Sleep is one of the most underrated forms of natural recovery,” says Thie. “People will spend hundreds of pounds on the best running shoes, drinks, energy gels and all those things. They go and pay for a massage, go and see physios. But sleep is our natural healer.”
“Our bodies are the smartest bit of technology, equipment and kit that we're ever going to get. You only ever get one. So, you've got to look after it and sleep is when it repairs.”
A 2023 study published in the National Library of Medicine by researchers from Athens and Zurich reviewed the relationship of strenuous physical activities like long-distance running with sleep.
The researchers found that the longer the distance of a running race, the greater the importance of an optimal sleep for race performance as well as the impact of a race on sleep.
It’s not all about the amount of sleep you get, but the quality of sleep too. A growing body of research suggests slow-wave sleep, otherwise known as deep sleep, is most important for recovery in athletes.
Slow-wave sleep is the deepest stage of non-rapid eye movement (NREM) sleep, which is essential for tissue growth, muscle repair and immunity strengthening.
This is because the body releases human growth hormone during this stage of sleep, aiding muscle tissue repair and regeneration.
Without sufficient slow wave sleep the body can’t repair the damage sustained to muscles, bones and tendons during intense training sessions like a long run or speed session.
As Thie explains: “If we think about our body like an electric car; when we fall asleep is when we recharge our body battery.
If we are awake longer and longer, then that battery runs down. If you're trying to run and exercise, you run the battery down even more, increasing the need for you to recharge through sleep.”
3 ways sleep can make you a better runner
While sleeping well is not going to miraculously make you a speed sensation. It is part of the puzzle of improving your running performance. Here's how...
1. Allows your heart to rest
Although your heart becomes stronger with every stride you run, it also needs time to recuperate.
As an intense cardiovascular exercise, running places stress on the cardiovascular system including your heart, meaning it is important to take good care of this vital organ.
Although the heart never stops working, your heart rate and blood pressure slow down while you sleep at night, giving it a much-needed chance to rest and adapt to your training.
“When you train, your circulatory system undergoes adaptation. So, your body starts to get better at delivering nutrients and oxygen to all the different muscles that are needed to run a marathon,” says Dr Gupta says.
And your body best adapts without burning out when you maintain a good balance of training and sleep.
Dr. Luke Gupta is a performance scientist with over 10-years of experience providing support to British Olympic and Paralympic sports. He is also a sleep scientist with a PhD at Loughborough University investigating the measurement and management of sleep health in high performance sport.
2. Strengthens the immune system
The last thing you want is to battle through your training block, sacrificing social activities for a long run and lay-ins for cold early mornings pounding the pavements, only to be struck with the flu on race day.
Under the physical stress of marathon training, our immune system can become compromised.
1. Your low intensity runs feel hard
2. You’re feeling sluggish even after rest days
3. Muscle soreness is more intense or lingers longer than usual
4. You’re more susceptible to injuries
5. Higher resting heart rate
“Doing lots of physical exercise on top of an already exhausting lifestyle is going to damp down your body’s responses to viruses and bacteria," Dr Gupta says. "But sleep can balance the books.”
Getting good sleep is key to building a solid defence against illness and injury as a runner because this is when the immune response kicks in.
“In the day, there's lots of different pathogens entering our bodies through eyes, nose and mouth," Dr Gupta explains.
"It's not until we sleep that our bodies actually start to form a defense to stop them doing any damage.”
3. Improves mental fitness
Marathon training is as mentally demanding as it is physically. A gruelling marathon training block requires mental endurance and can be stressful, especially when you’re juggling increased training alongside full time work and family commitments. Again, sleep can help.
“Sleep can have a profound effect on the cognitive and emotional elements of running," Dr Gupta says, explaining that "It can boost your motivation to train, your ability to make [pacing] decisions and your ability to sustain attention, which are important in long distance running.”
Sleep primes your mental state to take on a marathon and all the waves of emotion and adrenaline race day will bring.
How I optimize my sleep for better training
1. I stick to a sleep schedule
Helping to regulate your internal body clock and hormone cycles, a consistent sleep schedule is the bedrock to quality sleep.
I aim to go bed and wake up at roughly the same time each day as this helps me fall asleep faster and wake up easier.
My sleep-tracking smart bed (the Eight Sleep Pod 4) helps me stay accountable when it comes to my sleep schedule as a consistent routine improves your sleep score.
Other sleep trackers I recommend include the Oura Ring and Garmin sleep coach.
With a consistent bedtime, your body will learn when it is time to wind down for sleep and when it should wake up and be energetic.
In turn, it will release and suppress the relevant hormones (i.e. melatonin in the evening so you feel sleepy and cortisol in the morning so you feel more alert.)
Most marathons start early in the morning and you must account for travel time to the start line too. So getting your body used to running earlier in the day after an early alarm is key to getting your energy peaks in line for race day.
2. I don't run too close to bedtime
My chronotype is a morning lark, which bodes well with marathon training. Granted, adding marathon training into a jam packed schedule means squeezing a run in where you can.
However, for the benefit of your sleep, I recommend a morning run over an evening one where possible.
This is because exercise spikes your cortisol levels and raises your core body temperature, which is no recipe for peaceful sleep.
Experts recommend avoiding intense exercise three to four hours before bed and swapping vigorous physical activity for gentler forms of movement in the evening like yoga or a walk (both of which can assist marathon runners.)
Plus studies show morning exercise is better for your sleep. A morning run outdoors exposes you to sunlight and spikes cortisol at the right time, helping you sustain energy throughout the day and regulate your circadian rhythm.
3. I relax my mind and body
Finding ways to manage the mental overload of marathon training is important for getting quality sleep.
I incorporate calming activities like reading, yoga and listening to music into my evening routine and rest days.
You’ve got to fit your training in somewhere and you're probably going to compromise your sleep at some point
This ensures I give my mind and body time to wind down before sleep and allow time to switch off and fully recharge between runs.
But I don’t let the pursuit of perfect sleep stress me out. As Dr Gupta reminds me: “You’ve got to fit your training in somewhere and you're probably going to compromise your sleep at some point.”
Accepting that not every night’s sleep will be perfect and not every run will be your best eases the mental pressure of endurance training.
4. I stretch before bed
Skipping stretching seems to be a common bad habit among runners. I admit I’m not the most dedicated stretcher and I often hear fellow runners say the same thing.
One way to put this running vice to bed and improve your recovery is carving out time in your bedtime routine to stretch your body.
Since replacing bedtime scrolling with bedtime stretching, I’ve noticed an array of benefits. My muscles feel less tense and I feel more relaxed by the time I get into bed, helping me drift off to sleep.
And my sleep score shows an improvement too, climbing from an average of 59 over a week before I established a solid nighttime routine to an average of 91 over a week in February with a calming routine, including stretching, in place.
Stretching before bed also releases endorphins which can alleviate stress built up through the day, so you go to bed in higher spirits, which does wonders for sleep quality. Anxiety and stress are two of the main disruptors of sleep, after all.
5. I keep my body temperature low
A sleep hack that many people aren’t aware of is controlling your temperature. This is because your body naturally cools down before you sleep.
Therefore, making an effort to cool your sleep space down, be that with a cooling mattress or by opening a window, can help you drift off to sleep and promote muscle recovery overnight.
While it sounds contradictory, taking a warm bath or using a sauna before bed can help you cool your body down.
This is because, although your body temperature rises while in the sauna or bath, once you exit there is a sudden drop in body temperature and this signals that it is time to sleep.
In response, your body will release melatonin, making you feel sleepy, drift off quickly and get those all important deep ZZZs.
6. I nap where I can
A common denominator in the world-record breaking marathon training schedules I mentioned earlier is the daytime nap.
If there’s one thing Thie misses about being a professional athlete, it’s the luxury of an afternoon nap. “I think countries where they have a siesta have got it absolutely spot on,” he says, because napping “doubles your recovery time, allowing your body to heal itself from the activities you've done.”
“If anyone has the ability to have an afternoon nap, absolutely have it,” advises Thie.
Taking this advice on board, I’ve napped where I can and when I think I need it. Working full time, this usually means a weekend afternoon nap after a long run when the extra kip is especially needed.
7. I refuel properly
Alongside sleeping well, properly refuelling with a nutritious, balanced diet is an essential recovery tool in the marathon runner’s belt, and your diet can influence your sleep quality too.
Endurance training depletes glycogen stores in the muscles therefore replenishing these stores with plenty of carbohydrates before and after a run is key to keeping your body functioning and sleeping well.
While heavy meals around bedtime are not advised, I always have a snack before bed to prevent nighttime awakenings due to hunger.
My nutrient-packed nighttime snack of choice is usually Greek yoghurt with almonds, seeds and peanut butter.
This is because almonds are rich in magnesium, which is well known for promoting sleep. Meanwhile, yoghurt contains tryptophan (an amino acid that regulates sleep), protein which helps avoid blood sugar spikes and calcium which promotes muscle relaxation.
How running can help you sleep better
The good news is that there’s a two-way relationship between running and sleep. While sleeping better can make you run better, running can also help you sleep better.
Studies show adults who exercise for at least 30 minutes a day sleep an average of 15 minutes longer than those who did not exercise. This is because exercise increases adenosine in the body, a compound that promotes sleep.
Essentially, exercise tires you out physically and mentally. In turn, your body craves more rest, helping you fall asleep faster and sleep through the night.
Research from the French Institute of Sport shows increased training load promotes sleep propensity and slow-wave sleep in endurance runners. So, while your body demands more deep sleep during marathon training, it usefully becomes better at gaining it.
Tom's Guide created this content as part of a paid partnership with Helix Sleep. The contents of this article are independent and solely reflect the editorial opinion of Tom's Guide.
