If a coworker is pale, confused, sweating, and feels "shaky", what is the likely cause of his symptoms?

The symptoms described—paleness, confusion, sweating, and a feeling of shakiness—are indicative of low blood sugar, or hypoglycemia. This condition occurs when the glucose levels in the blood drop significantly, leading to symptoms as the brain and body are deprived of the essential energy source they need to function effectively.

When a person experiences low blood sugar, their body may respond with symptoms such as irritability, shakiness, sweating, and confusion due to the brain's immediate need for glucose to maintain metabolic activity. Additionally, pale skin can occur as the body diverts blood flow to vital organs, and the confusion can result from inadequate glucose levels affecting cognitive function.

While dehydration or low blood pressure can also present with some similar symptoms, they do not typically lead to the combination of shakiness and confusion in the same manner that low blood sugar does. High blood pressure is often asymptomatic and does not correlate with the acute presentation shown in this scenario. Therefore, low blood sugar is the most likely cause of the symptoms described.