Photo: Francois D'Haene during the 2017 UTMB ! He got it very right !

Well, this is one of the most important factors of your final preparation. To arrive rested, recovered, but still with a hot steel and tons of willpower and motivation. You need some sharpening workouts for sure, but getting sleep, mobility, hydration and nutrition right is more crucial.

I really find that generally humans don't drink enough, but athletes definitely not ! I mean even the general recommendation is just off the chart low: 1.5 for women and 2L for men. I would die if I drank only that little. Other guidelines from GB says 6 to 8glasses of water a day. What is that ? A glass of 2 or 3dl most likely. 6 x 2dl is 1.2L of water. 8 x 3dl is 2.4L of water. Even the high-end is extremely low. The Dietitians of Canada comes very close to okay with 2.2L for women and 3L for men. Of course that can change with extreme cold or heat or sedentary days and lifestyle.
There are researches on all kind of injuries and sport performance. Increasing hydration can lower pain status of lower back. Better hydration can make you avoid tendonitis, but also can help you get rid of it faster.

The drink to thirst advice is great, I mean that is the most natural. Unless your body is skewed ! Also, people often resist thirst to type 100more words on the computer. No wonder that the afternoon workout won't go well. I used to have a 60minute walk to the gym and then back when was training for strength and power. Each way I consumed 1L of water, plus another during training. Summer can double your needs, but rest and relax days normalise your hydration! I might be completing a 3h run in the morning and a 4hour bike ride in the afternoon. My 7L of water consumption is normal in the 35°C heat. Next day while reading a book in the shade for 10hours will demand only 3.5L of fluids. There is no rigid rule, but 2L or even 2.5L in any circumstance, for a grown active men/athlete is not going to cut it ! Even if you were 56kg and 168cm !

Hydration status

Drink salty, drink plenty, not too much but enough. Plain water is life giving and necessary. However if you have like a strategic nutritional plan with high fat low carb periods for instance, that can shed salt. 1g of carbohydrate is stored with 3g water. If you loose glycogen, you loose water, you loose salts. In addition the body retains, uses and eliminates salt differently while in a real fat burning state. I don't talk about ketogenic levels or any special dietary habit. Simply, if you ate an avocado and nuts with a coffee for pre run breakfast and post run you consumed omelette with olives and cheese, your salt stores will be a little empty before dinner. Most herbal infusions, tea and coffee are also slightly diuretic. It means loss of salt too.
It is important to use minerals in some of your drinks and eat mineral rich foods. Celery, beetroots, carrots and most root vegetables are extremely high in minerals. If you were healthy, drinking some home made low caloric juice even in the 3 days prior to race is a good idea. Some sensitive people would be rather munching on burgers, as a simple 2dl fresh celery, beetroot, cucumber, ginger and lemon would make them a rocket launcher. A healthy stomach can actually, on the contrary, extremely easily digest a litre of veg-juice ! Easy ! Why juice ? To avoid fibre !
Other sources can be full spectrum salt, magnesium flakes, epsom salt baths, sea bathing or if needed pharmaceutical mineral supplements. Magnesium, Zinc, Calcium, Sodium, Potassium...

This is important to get your body charged up in all areas with minerals. Achieving an optimal mineral status will change brain chemistry and muscle contractions very positively.
We often talk about being prone to cramps or cramping associated with minerals. If you had only inner thigh or calf cramps, yes, that is not from direct dehydration or hyponatremia ! Those issues cause cramps in the entire body ! I had them. Even my eye lids were cramping. When I stretched my calves, my lower back, gluts and hams went on cramping. When I stretched my calves, my anterior tibialis and psoas were cramping. The little muscles on the top of my hands were cramping. While holding on to the wall, my triceps and shoulders went haywire too!
Those thigh and calf cramps come from individual under-training issues. Some guys can run 2:25 marathons while their longest run is 20km a couple of times. Others must run every weekend 30 to 35km to make sure that their body is ready. Training plan and execution mishaps, foot strike patterns, running technique, core strength weakness, breathing and general lack of mobility what are the most likely causes of inner thigh and calf cramps. Unpreparedness ! There are climbs and descents during the race and you trained all flat ? Trained on the road for a trail race ? Your longest hills are 400m but there are D+2000m climbs and descents ? No wonder you got cramps !

I simplify, personally. I make sure to get in 3L of water every day for 2 weeks out from my race. I am 198cm for 80kg. 1.5L of that is quality mineral water. I drink at least 1L of tea and hand-picked herbal infusions daily. One or 2 home-made organic quality coffee. Not espressos, but long shots of 2 to 3dl mugs. I also often make stews and soups, drink some almond milk and smoothies too. Only fluids I have around 5L a day, but 3L of that is water for sure !
I salt my food with Himalayan salt, sea salt and rock salt. Yes I have 3 salts at home, choosing always different brands and using a different one each time.

Some of this might sound complicated or over doing, but people come to me to find solutions. To find out what causes problems. What causes them to not to be able to perform as they want. Most hydration issues do not come from race day execution, but from the weeks before. There are many marathoners run an entire race not touching water or food, with no issues what so ever.

Have some questions, ideas or comments ? Please post it down below.

Unfortunately I cannot write a book here to express all levels of hydration, but pre and in-race hydration should be naturally modified for longer and shorter events, altitude and climate, equipment carried and the type of movement too. Also while taking risks during a race might pay off, taking risks during individual wilderness adventures will never pay off. This means that skipping the last aid-station to win 1minute over your challenger might let you get away with this, on the final 10km with 1dl of water. However when you don't know that a stream or a river will be there where you are going, you should be filling up your bottles and bladders every single time you come across water.