On average, yes. People with major depression tend to have lower resting heart rate Resting heart rate How many times your heart beats per minute while you are fully at rest. For adults it is usually 60 to 100 beats per minute, and lower in well-trained athletes. More about Resting heart rate variability (HRV) than people without it, and some antidepressants can lower it further. The gap is modest, and HRV cannot tell you whether you are depressed or whether treatment is working.
What the research shows
Several large reviews have compared resting HRV in people with major depression and people without it.
- Unmedicated adults. A 2019 review pooled 21 studies with 2,250 adults with major depression who were not taking medicine and 1,982 people without it (Koch and colleagues, 2019). HRV measures such as RMSSD RMSSD Root mean square of successive differences: an HRV metric built from how much each heartbeat interval differs from the next. It mainly reflects vagal activity. More about RMSSD , SDNN SDNN The standard deviation of all NN intervals in a recording, in milliseconds. It measures overall variability, and its value depends strongly on how long the recording lasts. More about SDNN and HF power HF power The share of heart rate variability in fast rhythms of 0.15 to 0.40 Hz, the range of normal breathing. It mainly reflects vagal activity when breathing is 9 to 24 breaths a minute. More about HF power were lower in the depression groups. For RMSSD, the measure most wearables report, the difference was small to moderate.
- Depression without heart disease. A 2010 review pooled 18 studies with 673 people with depression and 407 without, none with heart disease (Kemp and colleagues, 2010). HRV was lower in the depression groups, and people with more severe depression tended to have lower HRV.
- Across mental health conditions. A 2016 review of 140 studies found lower HRV in mood, anxiety and psychotic disorders, and the gap remained in people taking no medicine (Alvares and colleagues, 2016). It also found that study quality changed how big the gap looked.
These are averages across groups. The two groups overlap a lot, so many people with depression have ordinary HRV and many people with low HRV are not depressed.
What about antidepressants?
Medicines are part of the picture, and the findings do not all agree.
- In the 2010 review, tricyclic antidepressants, an older group of drugs, lowered HRV. SSRIs and two other antidepressants (mirtazapine and nefazodone) had no clear effect (Kemp and colleagues, 2010).
- A Dutch study of 2,373 adults found that people taking SSRIs, tricyclics or other antidepressants had lower HRV than both healthy people and depressed people not taking medicine (Licht and colleagues, 2008). Once the researchers took medication into account, the link between depression and SDNN disappeared, and the link with breathing-related HRV became much weaker. The authors concluded that antidepressants seemed to drive much of the difference.
- The 2016 review found smaller but real drops in HRV with some antidepressants and antipsychotics (Alvares and colleagues, 2016).
So depression and its treatment can both pull HRV down, and in a single reading you cannot tell which is which. Antidepressants are prescribed for good reasons. Never stop or change one because of your HRV; if the number worries you, raise it with the doctor who prescribed it. For other medicines, see do medications affect HRV?
Why depression and HRV might be linked
HRV mostly reflects the calming branch of the nervous system, which slows the heart through the vagus nerve Vagus nerve The main nerve of the parasympathetic nervous system, running from the brainstem to the heart, lungs and gut. Its fast signals to the heart drive most beat-to-beat HRV. More about Vagus nerve . Lower HRV in depression points to less of that calming input. The lesson on the nervous system behind HRV explains how this works.
The studies show a link, not cause and effect. Depression often changes sleep, activity, appetite and alcohol use, and each of these can move HRV on its own.
What to do with your own data
- Don’t use HRV as a mood test. A low reading after a poor night or a cold looks the same as one on a low day. See what low HRV can mean.
- Note big changes in your routine. If you start or change a medicine, tag the date in your app. Your baseline Baseline Your own usual HRV level and range, built from weeks of readings taken the same way. Comparing a reading with your baseline says more than comparing it with other people. More about Baseline may shift, and the tag keeps you from reading that shift as a bad week.
- Step back if tracking makes you feel worse. A number that drops every morning can feed worry or low mood. Weekly averages are enough, and taking a break is fine.
When to talk to a doctor
Depression is diagnosed from symptoms, not from a heart reading. The US National Institute of Mental Health says a diagnosis needs symptoms most of the day, nearly every day, for at least two weeks (NIMH). These include low or empty mood, losing interest in things you used to enjoy, feeling hopeless or worthless, tiredness, and changes in sleep or appetite.
If you are struggling, talk to a doctor, whatever your HRV shows. If you have thoughts of harming yourself, contact your local emergency number or a crisis line straight away.