This article is the fifth in a series on nutrition and will focus on hydration.Throughout all of our lives, we are constantly told to stay hydrated.Living in Israel, especially, people are very aware of the need to stay hydrated, to constantly be drinking enough water, lest their bodies suffer from dehydration.If the general public is cognizant about this issue to such an extent, then all the more so do athletes need to be aware of the importance of staying hydrated.The human body is composed of 55-70 percent water (depending on how muscular one is), and when one sweats, fluid is lost, which can lead to dehydration.Essentially, staying hydrated means maintaining the levels of fluid in the body. Dehydration occurs when one does not drink enough fluids to replenish those lost.Fluids are crucial for the body to function properly, and while one’s body can function for several days without food, it can only last a few days without water.The body’s cells and organs use water to carry out basic operations such as the transport of oxygen and nutrients, removal of toxins and waste materials, controlling heart rate and blood pressure, regulation of body temperature, creation of saliva, lubrication of joints, and other key functions.Before we can learn about how to stay hydrated, we need to understand how our body becomes dehydrated.Every day the typical adult will lose approximately 10 cups of water (those who are very active will lose more) through natural processes such as going to the bathroom, sweating or breathing.People eat and drink to replenish these fluids lost, when feeling thirst or hunger.Many assume that if one does not feel thirsty then he or she must not be dehydrated; this is in fact, a false assumption. Many people who are dehydrated do not experience symptoms of thirst; therefore thirst is not the best indicator of water levels in the body.When people exercise they lose fluids through sweat.Interestingly enough, however, we are not always aware that we are sweating – it’s therefore always important to drink at all times, regardless of whether we think we need to.It is suggested that one weigh oneself before and after physical activity in order to calculate how much fluid was lost. You must of course also make a note of how many liters of fluid you consumed during exercising.Age also affects how much fluid is lost. Infants, children, older adults, anyone overweight or obese and women are at a greater risk for dehydration.The body’s ability to store water as a person ages decreases.Some symptoms of dehydration are irritability, fatigue or weakness, nausea, headaches, dizziness, lightheadedness, dry or sticky mouth, swollen tongue, constipation, dry skin, weight loss, decrease in urination and concentrated urine.It is a good idea to always be conscious of how much water one is drinking as to avoid a situation of dehydration.Obviously, one needs to drink more than usual when ill, engaging in physical activity or when the weather is extremely hot. This will greatly reduce one’s risk of dehydration.Often, one suffering from dehydration (whether mild, moderate or severe) will find it difficult to eat or drink, which means that the fluids lost will not be replenished.When in this situation, there are some tips that can help to rehydrate your body.It is a good idea to suck on ice cubes, or popsicles, especially when one cannot eat or drink.Keep a water bottle with you at all times so that you will not have to waste your energy getting up to get more to drink, until you have regained your strength.Instead of drinking large gulps of water at once, it is advised to drink small amounts of water at regular intervals.It is a good practice to drink a large glass of water before going to bed and before waking up each morning.One who suffers from diarrhea should choose beverages that contain sodium and potassium in order to aid in the replacements of nutrients lost.With severe dehydration is it strongly recommended to go see your doctor or to go to the hospital.Next week, I will continue the subject of hydration and discuss just how much water we should be drinking.