I read somewhere that one big reason why the labels on pain relievers stress that we should drink a full glass of water with their pills is because, a lot of the time, the person with the headache is simply dehyrated and needs water. The water gets rid of the headache! I have found that when I don't get enough water, it definately makes it harder for me to concentrate and when I get caught up in tarot or AT, I have to remind myself to take breaks and drink water.
I have a hard time drinking a lot of fluids but I need to for medical reasons. If you hate drinking water (like me) there are others things you can do to get those fluids in. My doctor helped me with this.
The best thing is to drink slips of water a lot. Don't go long stretches without water, especially in warm weather and while exercising. For some reason my kidney really acts up in the winter though so its important to remember that even when you are cold, you still need water. Drink a lot of water when you first wake up in the morning too--it helps start the day right. And by the time you feel thirsty, you are already dehydrated. The same thing with food--smaller meals at regular intervals are important.
Don't forget you can add lime or lemon to your water. I absolutely love metromint water (peppermint water and now they have a spearmint one.) You can get it in many health food stores.You can make your version by brewing mint tea (don't let it steep too long) and then refrigerating the results. Honey Vanilla Chamomile tea tastes great cold also if you dislike hot tea. (Chamomile is good for the stomach and is soothing for the nerves.) I drink tea a lot and it helps. I usually have a cup of tea while I read but I keep the cup on the floor so I don't accidently spill any on the cards.
If you have to drink soda, limit how much and stay away from ones with dyes--stick with the ones that you can see through. This is less taxing on the body because it is hard on the kidneys to filter that. Also try to watch how much juice, soda, alcohol, etc you are drinking because they have a lot of sugar and will affect your blood sugar levels. And when those levels get high, it usually results in hunger and a desire for even more sugar!
If you think that your readings are just taxing you spiritually and mentally,
maybe it's just that you are juggling too many different things and you are feeling overwhelmed. If so, you may need to cut back on some things and/or look into meditation, relaxation techniques. And we can't forget the importance having some time for yourself to regroup and getting enough sleep! There are also vitamins and herb out there that may help you in regards to mental clarity and focus.