Nutrition Tips for Indoor Triathlon Training

by Claire Fudge

Hands up who has embraced more indoor turbo-training with lockdown than ever before?!  Some athletes have even bought treadmills and set up their own pain caves at home! 

Whilst training inside doesn’t change your requirements for carbohydrates or fluids it may be that the intensity does.  Often when we do an indoor turbo session it may be more intense, shorter, sharper; a snappier session than when we ride out for 3hrs.  The same goes for a treadmill session; treadmill training is a great way to set out some specific interval sessions. 

Nutrition tips for indoor triathlon training

Does indoor training change our fuel needs? 

It depends…… if you are performing a high intensity session for 45 minutes or longer you may need to think about topping up your carbohydrates even if you have fuelled pre workout. 

Making sure you have adequate glycogen stores for most athletes is a focus for the last meal. If your last meal was more than 3-4hrs ago, you may need to think about a top up snack about 1-2hrs pre session.  This should be based on carbohydrates and can include some slower release carbohydrates especially if you are not fuelling within the session. 

Nutrition tips for indoor triathlon training

For example slower release carbohydrates could be oats, oat cakes, quinoa or sweet potato. 

A snack pre-training may include about 60g carbohydrates; aim for a snack containing between 1-4g/ kg of body weight (1). 

What about two quinoa rice cakes topped with a large mashed banana and a large glass of fruit juice or smoothie  (40g carbohydrates)?

Or a wholemeal bagel topped with jam and a low fat yoghurt (70g carbohydrates)?

Nutrition tips for indoor triathlon training

Should I fuel during an indoor training session?! 

Muscle glycogen is not limited during a high intensity session of about an hour - as long as there are already stores of glycogen (stored carbohydrates) present!

Of course there are many reasons for planned training with lower carbohydrates stores but if we are looking to fully fuel a high intensity session then carbohydrates remain king.

If the session is 45-75min and high intensity (think a big gear or FTP based session on the turbo) then you could simply mouth rinse with a carbohydrate solution! 

Yes this really is a thing!  Did you know that just the contact of carbohydrates in the mouth may stimulate parts of the brain and central nervous system involved in well being (2)?  This means simply rinsing your mouth with a carbohydrate based drink and spitting it out maybe enough to stimulate an enhanced performance by 2-3% (1)

Not particularly practical for an indoor session however! 

So if you feel the session is a full-on session then you may want to consider 30g of carbohydrates.  This may be as easy as sipping on an isotonic drink containing some carbohydrates.

Nutrition Tips for triathlon indoor training

Do I need to drink more when indoor training?  

On the topic of fluids; many athletes have no idea how much they may drink but the perception of most athletes is that they “sweat a lot”!

It is interesting; most athletes can see this big puddle on the treadmill or turbo mat, but is it any different from when they are outside? Or do we just see it because it is on the floor? 

Likely we are seeing more of the sweat, as when we train outside there is more airflow and so can evaporate sweat more easily, so we don’t notice it as much.  Also with more intense sessions we heat up more as our muscles work harder.  When we train inside it tends to be hotter and more humid; again affecting our ability to cool and evaporate sweat from the body.  So we may sweat a little more as our body struggles more to cool the body down.

This doesn’t mean simply swigging on litres of fluids because they are accessible, but rather we should make sure that we start the session well hydrated, perhaps with some additional sodium (salt).  It is also a great idea to carry out a number of sweat loss tests to make sure that we are only consuming what we need and not over-hydrating which is very easy when you are inside with fluids being in very easy reach!

 Nutrition Tips for Indoor triathlon training.  Jan Frodeno and Maurten

Most athletes can tolerate between 400-800ml of fluids during a session and depending on how much sodium your sweat contains and how much of a heavy sweater you are  it may also be useful to add some additional sodium into the bottle as well to help retain the fluid. 

What to eat and drink after an indoor training session?

Recovery after your indoor sessions is just as important as after any other session; with sufficient protein (0.4g/kg body weight or about 20-30g) along with carbohydrate (starting at 1g/kg body weight). 

So whether this is a tuna fish and salad sandwich or quick chicken stir fry with basmati rice make sure to replenish your glycogen stores and repair. 

Remember indoor sessions are usually pretty intense and hot!  So plan your nutrition to fuel your session and optimise your hydration.  With winter in full swing and snow on its way we may all be performing more indoor sessions!

Nutrition tips for Indoor Triathlon training


About Claire Fudge

Claire is an expert sports nutritionist and high performance dietician, as well as an iron-distance triathlete.  She heads up 4th Discipline, a leading triathlon-specific sports nutrition resource.



  1. Louise M. Burke, John A. Hawley, Stephen H. S. Wong & Asker E. Jeukendrup (2011) Carbohydrates for training and competition, Journal of Sports Sciences, 29:sup1, S17-S27, DOI: 10.1080/02640414.2011.585473

  2. Thomas, D. & Erdman, Kelly & Burke, Louise. (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics. 116. 501-528. 10.1016/j.jand.2015.12.006.