Pupils, the dark circles in your eyes, are usually equal in size. Unequal pupils (anisocoria) may be a sign of a medical issue. Certain medications placed in the eyes can cause the pupils to be ...

The changes with age occur in everyone but not necessarily at the same rate, therefore accounting for the difference seen in some people between chronologic age and physiologic age. The changes in ...

Another important influence on mood is the circadian rhythm that governs the timing of much physiological activity, most prominently the sleep-wake cycle. Disturbances in biological rhythms are ...

One study examined the effect of nature experiences on reductions in salivary cortisol and alpha-amylase concentrations, two biomarkers of physiological stress. These researchers found that a nature ...

Anxiety sets up a vicious cycle with sleep. Anxiety is a state of neural and general physiologic arousal. The hypervigilance that is a hallmark of anxiety keeps the brain in a constant state of ...