An increase in hormones associated with stress could lead to frailty in later life, a new study suggests.
Researchers from Helmholtz Zentrum Munchen in Germany carried out an analysis of 745 patients aged between 65 and 90.
Their levels of the stress hormone cortisol were measured via saliva samples at three times throughout the day - when they woke, 30 minutes later and in the evening.
It was discovered that lower amounts of the chemical in the morning and higher levels at night were found in patients who were classed as being frail.
Symptoms that led to participants being diagnosed with frailty included exhaustion, feeling weak, significant weight loss, slow walking speed and a lack of energy to take part in any physical activity.
Hamimatunnisa Johar, who co-wrote the study, said: "Our results suggest a link between disrupted cortisol regulation and loss of muscle mass and strength as the underlying pathophysiology of frailty."