Dear Doctor,

I feel dehydrated every morning despite being totally fine when going to bed the previous night. What causes this feeling? Erica

Dear Erica,

How long have you had these symptoms? Is it persistently daily or it occurs periodically?

Dehydration is a state of fluid deficit of the body. This can occur if much fluid is lost or intake is inadequate. When fluid loss exceeds intake of fluid, dehydration sets in. Early symptoms are dryness of mouth and passing dark colored urine. If this persists, one develops weakness, syncopal attacks, muscular cramps, exhaustion, oligurea (reduced quantity of urine). The kidneys are damaged and one can go into shock. Severe dehydration can be fatal due to electrolyte imbalance and cardiac arrest.

Diabetes with high blood glucose levels is one of the most common causes of dehydration and dryness of mouth. This happens because during day time a person may be drinking water to quench the excess thirst (a feature of high blood glucose due to uncontrolled diabetes), but at night after sleeping, 7-8 hours may pass without drinking, leading to dehydration.

Alcohol taken at night before sleeping can also cause dehydration in the morning. One can have it due to recurrent cold and blocked nose. Somebody suffering from chronic constipation can have sensation of dryness of the mouth in morning.

Rare hormonal disorders like diabetes insipidus, syndrome of inappropriate release of antidiuretic hormone (SIADH) can cause dehydration in the morning.

Very high temperatures as with summer months in a hot tropical climate can lead to dehydration if adequate cooling measures are not present.

Diarrhoea, vomiting, high fever are other conditions which can lead to dehydration. At times, dehydration can occur in the morning when one did not take adequate amounts of fluids/water the previous evening.

If somebody has been taking alcohol, it is better to reduce the quantity consumed and avoid taking it at bed time. Hot steam inhaled before sleeping for those suffering from recurrent cold is beneficial in preventing dehydration in the morning.Taking a healthy balanced diet with plenty of green vegetables, fruits and adequate amounts of water helps prevent and treat constipation. Adequate relaxation is also useful.

Getting tested for diabetes helps to detect it at the earliest and control it. Thus long term complications are prevented.