Normally, levels of the stress hormone cortisol are highest in the morning and lowest at night. But for older people, when there is disrupted cortisol regulation and this pattern is flipped (meaning cortisol is higher in the evening and lower in the morning), the risk of frailty is increased, according to a new study.
The findings are especially important given that frailty is a known risk factor for falls, hospitalization and even death risk.
"Our results suggest a link between disrupted cortisol regulation and loss of muscle mass and strength, as the underlying pathophysiology of frailty," study researcher Hamimatunnisa Johar, a Ph.D. student at Helmholtz Zentrum München, said in a statement. "In a clinical setting assessment of frailty can be time-consuming, and our findings show measurements of cortisol may offer a feasible alternative."
The research, published in the Journal of Clinical Endocrinology & Metabolism, is based on data from 745 people between ages 65 and 90. The participants had their saliva cortisol levels measured when they woke up in the morning, 30 minutes after waking up, and then again in the evening.
Frailty was defined has having at least three of the following characteristics: Physical inactivity, weakness (based on grip strength), weight loss of more than 5 kilograms (11 pounds) over six months, and exhaustion.