Why should we hydrate?
When we do not have enough water or salts during running or any other time, it can result in cramps (salt/water imbalances have known to be causes of cramps), early fatigue, declined performance, dizziness and in severe cases fainting. Make sure to hydrate before, during and after the exercises. As the amount of water we lose during exercise increases after about an hour of exercise), just drinking water will not suffice to hydrate. Salts (sodium and potassium) have an important role to perform in the process of hydration. Too much water and too little salt can lead many conditions - for e.g. A low concentration of sodium in the body is called hyponatremia (http://en.wikipedia.org/wiki/Hyponatremia). This is as dangerous if not more than dehydration.
How to Hydrate?
Before a long run: Having a glass of water before the run, would be a good idea. The night before the run, having a little bit more water than usual is a good practice. But, be careful about not overdoing it - else, you will have a disturbed sleep, going to the bathroom a few times in the middle of the night.
For moderate exercise (in our group this would amount to running for about an hour or less) just water and if facing mild symptoms of dehydration - electral would suffice. You need not force yourself to drink water every time you see an AID station! In general though, smaller quantity (small sips) and in more frequent intervals . Learning to run with a bottle does help to listen to your body's needs. Drink water when you feel like it. Listen to your body and go by thirst levels. Do not glug or drink a lot of water in one go - It does not help solve the issue.
For longer durations (typically for those training for half marathons and more) or for runs longer than a hour or more, it would not be smart to have just water. It is important to learn to know the right electrolyte balance for your body. A thumb rule is to take some form of salts every hour or so. It can be in the form of salt pills, electrolyte drink or fruits like bananas which have good amounts of potassium and sodium. If there is severe humidity or heat, then you can increase the freqency of salt intake; but, be careful about taking in too much salt as well. Too much salt with not enough water can cause nausea and vomiting.
What happens if I over hydrate or consume too much of salt during workouts?
As the amount of water we lose during exercise increases (after about an hour of exercise), just drinking water will not suffice to hydrate. Salts (sodium and potassium) have an important role to perform in the process of hydration.
Too much water and too little salt can lead to many conditions - for e.g. A low concentration of sodium in the body is called hyponatremia (http://en.wikipedia.org/wiki/Hyponatremia). This can be dangerous. Swelling up of body parts like hands, feet, face etc. can be indicative of fluid accumulation.
An overdose of salts is also not a good thing! It can result in nausea and vomiting as it affects your blood pressure as well.
How should I plan my post run hydration?
Post long-run, one should keep consuming water throughout the day and be watchful. Consumption of water really depends on the hydration levels of your body. What would be a useful indicator is the color of your pee. Track it and if its plain like water, your hydration is going well. If it is yellowish, it indicates that you are low on hydration - have more water and salt in regular intervals. The quantity of urination also goes down when you are dehydrated.
What should runners eat in general?
Good nutrition is necessary for the human body, irrespective of your running distance. You do need to take care of nutrition, even for a 10k runner. Runners need a lot of energy, hence your diet should contain 55-60% of complex carbohydrates. This can be obtained from vegetables, fruits, as well as whole grains. The food releases energy slowly into the body when you consume complex carbohydrates. This assists you when energy is required over a long period of time. It is also important to consume proteins and unsaturated fats. Proteins repair muscle tissues. They are the building blocks for muscles, bones, tissues, cartilages, blood. Unsaturated fats are good fats and can be obtained from almost all nuts, fish, some vegetables like olives & avocado, good oils like olive oil etc.
To summarize, eat every meal in the day with carbohydrates (roti, rice, ragi, oats, bajra , vegetables, fruits), proteins (dals, fish, chicken, yoghurt etc), fats (use good oils for cooking, almonds, walnuts etc). Our Indian diet contains all of this, hence stick to this diet, eat in moderation and eat at regular intervals.
What nutrition is considered most appropriate during the run?
There is no magic formula for this! Every runner has to figure out the food/nutrition plan that works for her/him.
There can be general tips like avoiding:
- oily foods
- acidic foods
General food that goes along well for most folks on a run:
- Fruits like bananas, citrus fruits (in moderation), watermelon etc.
- Boiled potatoes
- Dry fruits/trail mix
- Carbs like rice, bread, rotis etc.
A runner has to zero-in on her/his nutrition plan by trying out variations during the training runs.
How often do I need to eat/drink on a long run (>10km)? Is there a rule regarding this?
During a long run, there is no need to stop at all aid stations. Listen to your body. Drink water before you dehydrate. Eating a banana is a good idea , as it is a good source of potassium and gives you instant energy. Eating water based fruits like watermelons, oranges etc is also good. Simple carbohydrates like a peanut butter/jam sandwich is good, as it releases instant energy. Do not overeat. Eat enough to battle fatigue.
Hydrate to avoid dehydration. Again, excessive water drinking is not recommended. Hence, listen to signals from your body. There is no one rule that suits everybody here.