Winter time can cause people to
not drink enough because of the
cold weather.  This not only leads to
dry skin, but dehydration as well.  Water is vital for the body to be able to flush out toxins and circulate the nutrition it needs.  Drinking enough water can help lower blood pressure and raise your metabolism.  Not getting enough water can cause you to feel sluggish and that can sabotage your workout routine.
What Ells can cause me to be dehydrated?
How much sugar are you consuming?  Yes the body needs a certain amount of carbs for good health, as long as it's the right kind of carbs.  Complex carbs like whole grains, brown rice, sweet potato, oatmeal are good.  Simple carbs from sugar not only elevate blood glucose levels, they elevate insulin production which leads to the storage of sugar in the form of fat.  Elevated levels of sugar in the blood can also act as a diuretic causing you to urinate more to get rid of the sugar the body doesn't need.  This can also lead to dehydration.  One of the worst is soda.  Your body naturally  creates carbon dioxide as a waste from cellular metabolism.  Our blood stream carries this to the lungs where it can be exhaled.  Introducing more carbon dioxide (the fizzy stuff in the soda) makes the body work harder to get rid of it.  Respiratory rate is elevated as a result.  The harder you breath the more water your lungs loose. Plus the sugar in the soda has you urinating more thus leading to dehyrdation. If your feeling sluggish and skin is dry, drink more water, and reduce the soda.