Chronic Disorders

If you have a chronic health problem, you may have more difficulty controlling symptoms and disease progression when on shift work or long work hours.12

Some illnesses have a circadian rhythm component, and as a consequence, shift work can exacerbate their symptoms. These include rheumatoid arthritis, asthma, cancer, hypertension and other cardiovascular diseases, and gastrointestinal disorders. Working during the "wrong time of the day" (for example at night) may make your medication less effective for controlling your condition.

This condition is usually most painful in the morning, in contrast to osteoarthritis, which gets more painful throughout the day.

Lung function is usually worse during the night, when cortisol levels are low and histamine level is elevated, and this is when exacerbations of breathing often occur.

Correct timing of antineoplastic agent dosing can influence susceptibility of cancer cells to the drug, while reducing the toxic effects on normal tissue.

Blood pressure is usually highest from 6 a.m. to early afternoon and is lowest at night; thus, timing of medication to follow this rhythm can be beneficial.

Heart attacks are most common in the morning, right after waking.

GI disorders are exacerbated by disturbances to circadian rhythms and poor sleep.