They recruited 150 adults between the ages of 40 and 60 who had at least one cardiovascular risk factor such as high blood pressure, excess weight, or a sedentary lifestyle. Before anything else, they determined each participant’s chronotype, essentially whether they were biologically wired to function better in the morning or evening. This was not anticipated. It combined a standardized questionnaire with 48-hour core body temperature tracking, a reliable marker of circadian rhythms.
