Step 1: Understanding the Question.
A person in a hot place sweats out both water and salt. The question describes someone who replaces only the water and not the salt, and asks what condition this causes.
Step 2: Key Concept.
Sweat carries sodium out of the body along with water. If a person drinks plenty of water but takes in little salt, the blood sodium level falls even though hydration looks fine. Low sodium disturbs how muscle fibers fire, and this shows up as painful muscle cramps. This exact picture, heavy sweating plus water only replacement, is called heat cramps, sometimes known as stoker's cramps in workers exposed to continuous heat.
Step 3: Detailed Explanation.
Heat stroke is a different, more dangerous state where the body's core temperature rises very high and the person often stops sweating and shows confusion or loss of consciousness. This is not about salt replacement.
Heat exhaustion happens from a large loss of both water and salt together, causing weakness, dizziness, and heavy sweating, but body temperature usually stays near normal and painful muscle cramps are not the main feature.
Heat cramps happen specifically when water is replaced but salt is not, causing low blood sodium and painful cramps in the muscles used for hard work, which exactly matches the description in the question.
Heat hyperpyrexia is another name closely tied to heat stroke, describing an extremely high body temperature, not a salt deficiency problem.
Step 4: Final Answer.
This worker is likely to develop heat cramps.