Biochemical profiles during a Michigan heat wave: Suggestion of nutritional disturbance

Biochemical profiles routinely collected at a university clinic from 631 outpatients during a July Michigan heat wave and from 698 outpatients during a preceding cool period in June showed a statistically significant shift in the vector of means for 17 biochemical variables. The shift in mean values of two essential electrolytes (potassium and calcium) was significantly lower in two of the four age‐sex groups studied. While these departures are not significant by ordinary clinical standards for individual patients, they are unlikely to occur by chance. The data are consistent with, but not proof of, the hypothesis that changes in dietary levels of essential minerals such as potassium and calcium may be associated with heat waves. Poorly balanced meals (tea and toast, beer and pretzels) are probably more widely consumed during hot, humid weather than during normal seasonal conditions and provide a target for preventive measures. Physicians should be alert for early and reversible signs of potassium depleti...