Which of the following indicates a decrease in muscle contraction due to excess calcium?

A decrease in muscle contraction due to excess calcium is most accurately associated with lethargy. When calcium levels are excessively high, it can disrupt normal muscle function. Excess calcium can lead to an increased threshold for muscle fiber excitation, resulting in weakened contractions and overall muscular inefficiency.

In this context, lethargy describes a state of sluggishness or a decrease in energy and alertness, which can occur when muscle contractions are impaired due to the dysregulation of calcium levels. Although excess calcium can also lead to other symptoms, lethargy specifically encapsulates the decreased muscle responsiveness and energy levels indicative of impaired function.

Muscle cramps result from increased excitability and can occur due to dehydration, electrolyte imbalances, or overexertion rather than solely from high calcium. Fatigue refers to a broader sense of tiredness or lack of energy and may not directly correlate with excess calcium levels affecting contraction. Cardiac arrest is a severe, acute condition that may arise from numerous causes, including extreme disruptions in electrolyte balance, but does not directly address the general decrease in muscle contractions experienced with lethargy. Thus, lethargy is the most appropriate choice to reflect the condition described in the question.