The Weight of Water continued...
"Dehydration is one of the leading causes of a lack of energy," says Grotto. If you're not well hydrated, your body puts its resources into maintaining your water balance instead of into giving you energy.
Everyone's water needs vary. In February 2004, the Institute of Medicine released a report indicating most people meet their daily hydration needs by using thirst as their guide. In general, the Institute's expert panel recommended that women get about 11 cups of water from food and drink each day, and men get about 16 cups daily. This may seem like a lot of liquid, but 20% of it comes from food and the other 80% from drinking water and other beverages. .
To adequately get your hydration needs, particularly on a hot and humid day, the Academy of Nutrition and Dietetics suggests carrying around a bottle of water, or replacing your afternoon soft drink with water. Frozen juice bars or icy treats are also a good idea.
Water is especially important after exercise, with certain medicines, and with a high-fiber diet. Your fluid intake should be adjusted to how much water you're losing, says Finley. "A simple thing like stopping at a drinking fountain when you walk by one is a good idea."
More than half of Americans reach for a coffee cup every day, and 25% drink it occasionally, reports the National Coffee Association. This should come as no surprise as there are those who swear they cannot function without the caffeine.
The compound can be found not only in coffee but in tea, soft drinks, chocolate, and herbs as well.
John Allred, PhD, a food science communicator for the Institute of Food Technologists, says stimulants like caffeine exaggerate the effect of natural hormones like adrenaline. "They get your heart pumping faster, you respire faster, and that gives you a stimulated feeling," he says, noting the results usually last no more than two hours.
Psychology tests have shown a combination of caffeine and sugar can improve alertness and performance. "But then it wears off, and then you get a little bit of a slump afterward," says Camire. The high-low effect of caffeine, she says, is not as pronounced as it is in sugar, but it is significant enough that frequent users often experience headaches without the substance.