33 tips to boost your endurance for triathlon

Going long this year? Then you’ll need to boost your endurance, or you’ll be more struggling sloth than Duracell bunny… Here’s how to supercharge your stamina with the latest research-backed strategies.

Triathlon is no easy ask for most people. Whether you’re attempting your first race this year or moving up to one of the longer distances, there’s no doubt about it – you’ll be doing three sports, plus transitions, and chances are you’ll be using up all your energy levels. Endurance is key then. Luckily though, this is something you can build into your swim, bike and run training in plenty of small ways, which will combine to make a big difference.

1. Be consistent 

Like any other training adaptation, improving your aerobic endurance and the health benefits that come with it requires regular, sustained work. 

A study published in the Journal of the American College of Cardiology found that between 60-144 minutes of moderate-intensity aerobic exercise – split across two to three sessions per week – was optimal in terms of both quantity and frequency to start to see benefits. 

Running coach Steve Bateman sums it up as ‘use it or lose it’. “The absolute fundamental is regular running,” he says. “Without that, you’re going to provide a stimulus from a run, your body’s going to make some adaptations if it’s good enough, and then if you’re not going to run for a bit, it’ll start to lose those adaptations again.” 

2. Fire up fat reserves 

Endurance-focused cardiovascular exercise is powered by the body’s aerobic energy system, which uses oxygen to transform your body’s fat and sugar (glycogen) stores into ATP. 

Your body has limited stores of the latter, but it’s possible to train it to use the former, saving glycogen stores for when you need them most. 

One study found that the sweet spot for metabolising fat was around 55% of your maximum effort, meaning you don’t have to flog yourself to start seeing the benefits. 

3. Switch the twitch 

Your muscles are made up of three types of fibre: slow oxidative (SO), fast oxidative (FO) and fast glycolytic (FG). SO responds well to slow, easy training and is slow to tire, while FG is best for sprinting. 

FO meanwhile is “kind of in the middle and can go either way depending on the training” explains Bateman. “If you go for longer runs at a lower intensity, then the middle types will adapt to be more like the slow-type fibres.”

4. Stay steady 

Training for long periods at an easy intensity might not produce the same level of post- workout burn as a HIIT session, but keep it up for long enough and Bateman says it will transform your body into a mile-munching machine. 

“Your body will adapt by increasing the size of your chest cavity and lung capacity, and your heart will increase in capacity and strength,” he says. 

“It’s having to pump blood at a higher rate for longer. It’s also having to make sure it can transport the oxygen, the fats and the carbs from wherever they are in your body to your muscles. Inside your muscles, you’ll promote the growth of new capillaries and new mitochondria, which are the energy-producing parts.” 

5. HIIT for the heart

The above isn’t to say you should shun high-intensity work altogether. 

The short, hard efforts – above 10k pace for runners, or functional threshold power for cyclists – “provide a stimulus for your heart to get bigger and stronger, which means being able to transport more oxygen to working muscles and to transport it more efficiently,” says Bateman. 

This is also known as improving your VO2 Max – the maximum volume of oxygen per minute that can be captured from the air and utilised by the aerobic energy Improve your V02 Max to allow muscles to work more efficiently. 

He recommends including high-intensity work from as early as the base-building phase of any training plan, beginning with short intervals and fewer repeats before increasing both as your plan progresses. 

6.Improve efficiency 

One way to boost your endurance is improving your efficiency – after all, using less effort means you can theoretically go for longer. 

While it’s possible to drill down into details of your foot’s landing when running, or how your hand is entering the pool when swimming, one simple way of finding better form is to add speed into the mix. 

“You want to achieve a higher intensity or faster speed, so you’re asking your brain to move your body in a different way than if you went out for lots of easy [sessions],” says Bateman. 

He recommends fartlek and accelerations – where you gradually increase speed from easy to almost a sprint between two fixed points such as lampposts – in the middle of a workout: 

“When you return to your regular [speed], some of what you just asked your brain to do stays with you.” 

Over a long period, this starts to improve neuromuscular aspects such as “the way that your brain transmits the nerve impulses down to your muscles and how strong they are and in what sequence.” 

7. Plump for polarised 

“The common theme in all top endurance athletes is that they do a lot of training,” says Jack Hutchens, professional triathlete and coach for Scientific Triathlon. To accrue the hours without burning out through fatigue, most adopt a polarised approach. 

Traditionally, this has meant training either at a low intensity or high intensity, with the majority spent at the easy end to allow the body to cope with the load. 

But Hutchens explains it’s important to not miss out on the middle ground: “If you’re preparing for an endurance event, that moderate intensity is the intensity you’re going to be racing at, so you need to spend some time around that.” 

He recommends keeping the volume of low-intensity work the same but adding in some moderate in place of high-intensity eight weeks out from an event.

8. Build resilience 

While consistency might be the aim of the game, solely focusing on your chosen cardiovascular exercise can actually increase your risk of injury – denting your chances of building your endurance long-term. 

“Most endurance sports have a very limited range of movement and you repeat that same limited range of movement thousands of times,” explains strength and conditioning coach Scott Pearson from Fast Fit Strong. 

“You’re overworking some muscles and underworking the opposing muscles. Most injuries that occur in cardio exercise are overuse injuries that are a combination of weakness on one side of the joint and a corresponding tightness on the opposite side of the joint.” 

Strength training, conversely, brings you through the full range of movement, loosening the tight areas, strengthening the weak areas and boosting things like bone mineral density. “It’s multifaceted and undoes what your cardio sessions do,” adds Pearson. 

9. Power up

Getting stronger isn’t just beneficial for injury prevention. Bigger muscles will increase your overall power potential, dragging your thresholds up with it. 

In endurance sports such as cycling, this allows you to put out more power for the same effort, or the same power for less effort. 

“Power is derived as a product of strength and speed, so if you can lift a heavy weight quickly, you are more powerful,” says Pearson. 

He adds that strength-based training outweighs plyometric “until you can squat with roughly double your bodyweight on your back”, which is when “speed of movement becomes more important than the actual strength”. 

Not many people are that strong, he adds, “so 99% of the time getting stronger will also get you more powerful.” 

10. Get back to basics 

It might be tempting to search out specific strength-based exercises to get the biggest gains, but Pearson says you’ll get “the biggest bang for your buck” from five basic moves: squatting, deadlifting, pushing, pulling, and bracing through your trunk. 

“I like to build up the reps until the people I’m working with are consistent and competent in the exercises,” he adds, “then I will slowly bring the reps back down and raise the weight up. There’s no real need to overcomplicate things much more than that.” 

11. Vary the load 

Like your cardio sessions, it’s important to vary the intensity and frequency of your strength training as you build your endurance to avoid non-functional overreaching and dangers such as chronic fatigue. Pearson recommends approaching strength training on a sliding scale that contrasts with your cardio work. 

“Most sports will be summer- based,” he says. “You can probably afford to cut back on your number of [cardio] sessions of those in the colder, winter months; so three or four [strength] sessions through the colder months, and one or two sessions through the warmer months. Your risks of overdoing it will also depend on where you are in your strength training journey.

“A runner who wants to start [strength] training now has massive room to be able to improve, and it’s likely they will still be improving for between six to 15 months of basic, consistent gym training. Alternatively, if you have someone with one or two years of experience, the volume needed to get further improvements will be harder.” 

12. Put a spring in your step

Working on your form can help you use less effort for the same amount of output – it’s why cyclists practise pedal drills and swimmers are constantly trying to perfect their strokes. But when an activity involves a rebound – such as when your foot hits the ground in running – it’s possible to improve efficiencies in the gym, too. 

Plyometric exercises such as box jumps and burpees “train the ability to store energy in your tendons and reuse it,” explains Pearson. “You’ll get stiffer tendons and you will be able to transfer that power through your body more efficiently. 

In running for example, every time I land on the ground, kinetic energy is stored in my tendons and I can reuse that on my next foot contact, so I store and reuse the same energy over and over again. 

He caveats that “for cycling and to a larger degree sports like swimming where there isn’t any rebound, it’s pointless” – and that it’s not without risks: “If you’re bounding, jumping and landing, and particularly if you’re not used to it, then you put yourself at risk. Moving with speed is more difficult than just moving, so there’s an added injury risk associated with that.” 

13. Stretch out 

While it might not get the heart pumping like a run, a Czech study found that those who practised an hour of yoga per day had better aerobic performance than those who spent a similar amount of time doing an aerobic- focused activity. Its authors suggested that an improved breathing technique could be behind the superior baseline figures. Even if you don’t have a spare seven hours each week to refine your downward dog, research suggests that two 50-minute sessions per week can improve lung capacity. 

14. Remember to rest 

As your body starts to make positive adaptations, it can be tempting to push yourself to train more frequently. But exercising more doesn’t always equal more improvements. “If you train every day, you’re not giving your body the space to make the adaptations,” says Bateman. He recommends a minimum of two rest days a week and believes simply getting them is more important than their timing. “One of the questions I ask when taking on a new runner is, ‘What days are you already fully committed and absolutely can’t do any training?’ We nominate those as rest days.” 

15. Maximise recovery weeks 

To really amp up results, recovery shouldn’t be limited to those two rests days per week. Most long- term training plans will include a two or three-week build phase, followed by a lower-intensity week that helps to really hammer home the adaptations. But it doesn’t have to feel like wasted time. “I do testing to see if [clients’] fitness has improved,” says Bateman. 

“Typically, they’re much shorter runs; they are high intensity but they’re much lower volume, so your body does get a rest during that week. You’re still training, because testing is training, then you’re getting a read on whether fitness is improving.” 

16. Sleep more

Sleeping is crucial for rest, recovery and getting your body ready for the following day’s training session. While it’s recommended that adults get between seven to nine hours of shut-eye each night, a recent study found that the optimum amount for athletes was 8.3 hours. The researchers found that participants had the best chance of getting enough sleep when hitting the hay between 10-10:30pm. 

17. Load up

Training consistently is only half of the battle. “If that stimulus never changes through progression, your body won’t keep adapting,” says Bateman. 

He adds that a good training plan will be based around progressive overload: “matching the level of stimulus to your body’s ability to handle it (progressive), and adding just a little bit more (overload) to continue causing adaptations.”

18. Amp up the accuracy

Noticing your endurance’s improvement is difficult to do from feeling alone? Luckily, there’s a wealth of tools built into even the most basic smartwatches that can help provide some hard evidence. 

“[Data] allows you to quantify what you’re doing,” says Hutchens, “so you can measure your progress in a more objective way,” says Hutchens. 

He adds that it can also be key on a day-to-day basis for keeping your training intensity in check. 

“Having paces or heart rate allows you to keep a cap on where you’re at and make sure you get the prescribed training intensity rather than above that. If you’re going too hard in each session, your body simply can’t recover.” 

19.  Remember who’s in charge

It’s important not to become a slave to the data in pursuit of endurance gains. 

Hutchens recommends that it should be used to influence rather than guide daily training: “I give power numbers, pace numbers, and heart rate numbers, but there is always also a rate of perceived exertion.” 

Generally ranked on a scale of 0-10, zero would be relaxing, while 10 would be an all-out sprint you can only sustain for seconds. 

“I encourage all athletes to use that and listen to Listen to your body, as well as using data from watches etc. their body first,” he adds. “The data is there to guide you – don’t get too hung up on it.” 

20. Form a routine

Training consistently might seem like a simple way of building endurance, but the reality can easily become much more difficult when you throw work, life and other commitments into the mix. The solution? Remove the choice. 

“You need to incorporate your training within your daily routine, just the same as you get up and go to work,” says Hutchens. 

“Motivation is limited and is for the occasions when things are against you – like when you’ve had to work late or the weather’s really bad.” 

21. Go for a goal

Struggling with motivation? Nothing adds a purpose to training like signing up for an event. 

“If you don’t have an end goal or an event to work towards, when you get up for that early morning session it’s easy to think, Why am I even doing this?,” says Hutchens. It’s not just applying a ‘stick’ approach to training, either, with the event at the end a carrot to look forward to. 

“You can meet like-minded people,” he adds, “and that could maybe springboard onto other things that allows you to get more out of yourself in the long-term.” 

22. Get competitive 

Looking to increase your training volume? It’s time to get social. 

A paper published in Nature Communications found that simply seeing that a peer had run further or faster inspired someone to push themselves that little bit extra on that day’s run. 

Apps such as Strava are an effective way to keep in touch. 

23. Master the macro

A solid training plan will only get you so far. To really ramp up your aerobic abilities, you need to nail your nutrition. 

“With macronutrients, I always suggest that people look at their protein and their fat first, ensuring that they’re adequate, with a periodised approach to carbohydrate – or fuelling for the work required,” says Dr Richard Allison, consultant in performance nutrition and clinical dietetics for the Institute of Sport, Exercise and Health. 

He recommends between 1.8-2g protein per kg of body weight, 1-1.1g fat per kg of bodyweight and a minimum of 100-110g carbohydrate per kg of bodyweight per day – adding more if you’re active. 

24. Think fast

It might sound counterintuitive, but exercising on an empty stomach may help improve your aerobic capacity. 

“If you include fasted training once a week, you get a cellular adaptation that increases both your aerobic capacity and your ability to recover from a muscle protein synthesis perspective,” says Allison. 

He explains that there is a master cell regulator – PGC-1alpha – that increases its responses when you conduct fasted training followed by a meal containing carbohydrates and protein. 

25. Crack carb loading  

Although not necessary for short sessions, what you eat before longer training days or events can have a transformative effect on your performance. 

Carb loading has been shown to delay fatigue and improve performance by 2-3% during endurance exercise longer than 90 minutes, and it’s recommended to consume 10-12 g of carbohydrate per kg of bodyweight per day up to 48 hours before a big day. 

But it’s possible to refine things further in the hours before starting, too. “If you’ve got at least three hours before the event, you want to be having a low-fibre, low-fat, high-carbohydrate meal,” says Allison. 

“The reason for the low- fibre and low-fat is that they can delay gastric emptying. 

“The hour before you start training, you want to include some more simple carbohydrates, which can be in the form of sports foods, supplements such as gels or sports drinks, or fruits such as a banana – that will give you some additional carbohydrate to allow you to perform better.” 

26. Top up the tank 

Even if you’ve optimally carb loaded, if you’re doing a longer event, you’re going to use up those glycogen stores at some point. 

Often referred to as hitting the wall, this is where your body has used up all your stored carbohydrates and starts the less efficient process of converting proteins and fats into energy. 

“The rule of thumb is that you typically don’t need intra-workout carbs until about 60 minutes in,” explains Allison. 

During sessions over an hour, he recommends starting at 1g of carbohydrate per minute (60g per hour), which can come from a sports drink or a gel for ease of ingestion while active. 

“The exogenous carbohydrate – stuff you’re taking during your workout – actually has a glycogen-sparing effect and you use that as fuel to produce energy”. 

27. Don’t forgo fats 

The aerobic energy system doesn’t just rely on the body’s carbohydrate stores. 

Fat is a key energy source, too, and intramuscular triglycerides (fat stored in muscle fibres) can be converted into energy when combined with oxygen. 

“Yes, carbohydrate is king, but in those aerobic activities, you’re also oxidising fat,” says Allison. While all fats contain 9kcals of energy per gram, there are healthy varieties – mono and polyunsaturated such as avocados, nuts and oily fish – that can be more beneficial for cardiovascular health. 

“Bad fats can obviously have negative consequences to health,” says Allison, “and these tend to come from overly processed foods and seed oils.” 

28. Drink up

Dehydration is a surefire way to hamper a workout – particularly beyond the hour mark. 

To delay fatigue through lack of fluids, it’s recommended to drink at regular intervals of every ten to 20 minutes, and consume between 600-1,200ml of liquid an hour. 

If the intensity is on the high side, it’s worth adding some carbohydrates into the mix, while sodium (which is present in electrolytes) might help with fluid retention on hot days.

29. But don’t overdo it

It is possible to have too much of a good thing, and overhydration can lead to a condition called exercise-associated hyponatremia – where the sodium levels in the blood become too diluted and can ultimately be fatal. 

Guidelines suggest that the best way to prevent taking on too much fluid is to drink to thirst, rather than constantly taking on water or sports drinks, with it better to be a little bit dehydrated than oversaturated. 

30. Give your aerobic capacity a shot 

 Looking to give your training a boost? A pre-workout cup of Joe could be the answer. “Caffeine can help with uprating heart rates and actually increases your aerobic capacity of the exercising muscle,” says Allison. 

He suggests 3-5mg of caffeine per kg of bodyweight about 30 minutes before starting exercise to feel the benefit, which translates roughly to a triple shot espresso for someone who’s 70kg. 

31. Prioritise protein

“When people think ‘endurance’, they’re not necessarily thinking about muscle mass, but dietary protein is really important for recovery,” explains Allison. 

The priority should be getting the correct amount of protein, which is closely followed by its quality and the amount of branch-chain amino acids (BCAAs), with timing the least important factor to consider. 

“The thing that can maximise your recovery and muscle protein synthesis is dividing up the protein and having it every two-and-a- half to three waking hours,” adds Allison. 

32. Use essential oils 

Suffer from delayed- onset muscle soreness (DOMS) after a long or hard session? It’s time to ramp up the omega-3. “The mechanism is unclear, but it’s been shown to reduce muscle soreness,” says Allison.

He recommends a high dose of approximately one gramme per 10kg of bodyweight. For reference, a 90g mackerel fillet contains 4.9g of omega-3, making it easier to achieve than you might think. 

33. Stock up on supplements 

On top of getting your ratio of macronutrients right, Allison suggests that other aerobic-enhancing nutritional improvements can be sourced quite easily through supplements. Beta-alanine “reduces the build- up of lactic acid in the muscle, so you can exercise or compete for longer”. 

A small, 2g daily dose of creatine “increases the muscles’ ability to produce energy”, while nitric oxide – which can be found in beetroot juice – “helps the exercising muscle to be more efficient with oxygen”. 

He stresses sourcing supplements from a reputable company and ensuring that they’ve been Informed Sport batch tested, to minimise the risk of contaminants that could cause a failed drugs test.