This part of my nutrition during exercise again starts with much beloved “it depends”. Regarding the type of exercise, it is probably most convenient to start with swim training, as my entire swim trainings are done without ingesting any drinks or energy. Except of inadvertent ingestion of pool water…
I also withhold any energy supplementation on runs, with exception of hard long runs, in which I try to finish with some quality efforts. These examples would be 8 km tempo run after 20 km of hilly run, or progression runs, where I increase the tempo every 8 km. On such occasions I would usually take a gel (22 g of carbs) before the final hour of the run. Mostly it’s probably more of a mental boost, much like rinsing mouth with carb solution. The presence of carbohydrates in mouth signals the brain that additional nutrition is coming and hence greater tolerance to fatigue can be achieved by this “brain-fooling”. And as most of my gels have also caffeine, I can really detect a clear energy boost for that extra edge on such hard runs.
As far as hydration goes on the run, I usually ear on the “less is better” side of water intake. I fully reject the mainstream belief, that you should overhydrate and that (slight) dehydration affects performance. I also believe that (as with other things) one can get adapted to running with lower water intake so my main guidance for water intake is thirst! Therefore all of my winter running in cold conditions is done without any hydration, even the long runs. Only when the temperatures go above 20°C I hydrate during long runs.
Nutrition on the bike is much the same as on the run. All recovery rides and rides in duration up to 3 hours are done without any energy intake. The only exception would be hard intervals, where I would take a bottle with approx. 40 g of table sugar in water to get this “mouth rinsing brain fooling” effect before each interval. I also do not intake carbs on some long rides in base period, where the main focus is only on aerobic endurance without any quality efforts in-between. I experimented with eating some nuts on these rides, but I didn’t notice any difference, so this habit was abandoned.
The rides, in which I do intake a significant amount of carbs, are those long hard rides in duration of over 4 hours, especially if they are coupled with runs immediately after. On such occasions I would mix 100 – 150 grams of carbs (table sugar and maltodextrin in 2:1 ratio) in water, where I take most of these carbs towards the end of the ride, when the performance needs to be high. I hydrate according to thirst with plain water. Those rides are also nutrition race-simulations, as I employ the same nutrition strategy in races.
To summarize, the bulk of my training is done without ingesting any carbs. Only when some quality is needed in longer efforts, I do intake gels in runs or sugar on the rides. I also need to emphasize the importance of a couple of race nutrition simulations, where one needs to approximate the limits of carb intake. Most importantly, one needs to determine the highest carb intake, as this is the critical limit. You can always ingest some carbs, if you feel low on energy, but you cannot empty your stomach (at least conveniently) in case of over consumption of carbs. Unfortunately, I couldn’t find those limits for myself elegantly, as described in my two carb-overconsumption incidents.