In light of circadian research, prescriptions like “Take Once Daily” are terrifyingly vague.

Just as each of our cells has a circadian cycle, tumor growth is rhythmic. Some lymphomas see a peak in cell division late in the evening, whereas gut lining divides 23 times as much in the early morning as it does at night.

.. “At the beginning, even the notion of circadian rhythms was considered to be astrology—the whole field!” remembers Lévi. “Now we have identified genes and proteins, and we know how they work, which has given the field a major credibility it did not have when I started.”

.. Test for grip strength in the early afternoon and you’ll underestimate the severity of an arthritis case. Test for allergies in the morning and you’ll miss the milder histamine responses. Even a basic thermometer reading could mean a fever in the morning but not at night.