Measuring a person's heart rate can help spot depression as it beats faster and is less likely to drop at night, study finds

Measuring a person's heart rate could be a way of spotting if they are suffering from depression.

Depressed people's hearts beat an extra ten to 15 times per minute on average during the daytime, a study has found.

Their heart rates fell at night – which is normal as we recover from the stresses and strains of the day – but less so than people who were not depressed.

Scientists discovered this after tracking the heart rates of 16 people with depression and 16 who were not depressed over four days and three nights.

They were able to predict who had depression, based on their heart rate alone, in up to 90 per cent of cases.

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Measuring a person's heart rate could be a way of spotting if they are suffering from depression. Depressed people's hearts beat an extra ten to 15 times per minute on average during the daytime, a study has found. (File image)

Experts believe that depressed people's hearts may have to work harder because their chronic stress or anxiety means that they are constantly in a low-level state of 'fight or flight'.

Inflammation in the body caused by poor mental health may also reduce activity of the vagus nerve, which helps to regulate heart rate. 

The findings mean people could detect early signs of poor mental health in themselves by using a 24-hour fitness tracker to chart their heart rate.

Dr Carmen Schiweck, who led the study at Goethe University in Germany, said: 'Normally heart rates are higher during the day and lower during the night.

'Interestingly, it seems that the drop in heart rate during the night is impaired in depression. This seems to be a way of identifying patients who are at risk to develop depression or to relapse.'

Study volunteers, who were a similar age in the depressed and non-depressed groups, wore miniature echocardiogram patches on their chest to monitor their heart rate day and night.

Previous evidence had shown that depressed people did have higher heart rates, but this latest research found that the difference is up to 15 more beats a minute throughout the day.

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Experts believe that depressed people's hearts may have to work harder because their chronic stress or anxiety means that they are constantly in a low-level state of 'fight or flight'. (Picture posed  by model)

For the first time, it emerged that people's heart rates fell less at night if they were depressed.

Daytime heart rates, which also fluctuated less in those with depression, could be used to predict the condition with 81 per cent accuracy.

Night-time heart rates were better, achieving an accuracy of 90.6 per cent when a computer programme analysed the readings to provide a diagnosis.

The authors of the study, which was presented at the virtual conference of the European College of Neuropsychopharmacology, caution that heart rate may provide a red flag for depression only in those who are very depressed.

The volunteers in the study, diagnosed by a doctor, had tried two types of antidepressants which did not work.

But if people can predict depression early, they can take action – by doing more exercise or seeking counselling – to try to cope better.

If depression alters the heart rate so significantly, this may help to explain its link with coronary artery disease and heart failure.