Heart rate and fitness: can talking therapy change your heart rhythm?

When your body has not yet noticed the day is over

Your heart rate and fitness carry you through the day: the inbox, the train home, the shopping and a conversation that keeps going round in your head. In the evening you sit down and notice your heart is still racing, as if your body hasn’t heard that the day is over. In bed you are already running through tomorrow, and in the morning you feel you never fully came to rest. Alongside your heart rate and fitness, the watch on your wrist may also show a number called heart rate variability, and it may be lower than last week. You wonder what that means, and whether the worrying in your head and the pounding in your chest are part of the same story.

Often they are, and a new review of the research adds a piece to that story. It looks at a widely used talking therapy for worry and low mood and asks a simple question: if your mind is doing better, does your heart change too?

You are not the only one

Worry and low mood are common. In 2023, 42 per cent of people in the Netherlands aged 12 or over had felt anxious or low in the previous four weeks, according to figures CBS published in 2024.⁠³ Among women it was 48 per cent, among men 37 per cent.⁠⁴

Across the North Sea, the picture is much the same. In April 2025, 18% of adults in Great Britain had moderate to severe symptoms of low mood, the Office for National Statistics (ONS) reported in 2025. The share was highest among younger adults: 26% of 16 to 29-year-olds.⁠⁵

Your body has its own figure too. In 2022, 44 per cent of Dutch adults met the Gezondheidsraad’s physical activity guidelines, CBS reported in 2023.⁠⁶ That means more than half did not.

So if your head is full and your fitness is not where you want it to be, you are certainly not alone. BioProfile’s free heart and blood vessel scan gives you a first picture of where you stand with your heart and your fitness. The scan is not a diagnosis. The scan gives you insight into where you stand today.

Why worrying shows up in your heart rate

Your heart does not tick like a clock. The time between one beat and the next keeps changing, a little longer, then a little shorter, and that change is called heart rate variability. A healthy heart is not a metronome. It adapts quickly to what you ask of it, physically and mentally.⁠⁷ Heart rate variability is not the same as your heart rate. You can read what counts as a normal resting heart rate on our page about a normal heart rate.

Much of that adjusting is done by the calming branch of the nervous system, which acts as a brake on the heart through the vagus nerve. Researchers read its activity from certain parts of the variation: the fast rhythm that follows your breathing, the high-frequency band, and the difference from one beat to the next, a measure called RMSSD.⁠⁷

It was already known that worry can show up in this rhythm. A 2014 meta-analysis of 36 articles compared 2,086 people diagnosed with an anxiety disorder with 2,294 people without one. The first group had a lower heart rate variability, a small to medium difference.⁠²

That finding is only a snapshot, though. It says that people who struggle with anxiety often have a less variable heart rhythm. It does not say whether that rhythm changes once those people start to feel better. There was also a second gap in what we know. Whether a talking therapy works is usually judged with questionnaires in which people score their own symptoms, and self-reports like these can be biased.⁠¹ A measure that comes from the body itself could serve as a second witness. That is where the new review comes in.

A new review from Southampton

The new piece of the story comes from a team at the School of Psychology of the University of Southampton in the United Kingdom. The first author, A. Alkout, also works at the Psychiatry Department of the College of Medicine at Kuwait University. The co-authors are A.H.B.E. Husaini (Nottingham University Business School in Malaysia and the University of the Bundeswehr in Munich), A. Kadan (University of Southampton), V. Parlatini (University of Southampton, Hampshire and Isle of Wight Healthcare NHS Foundation Trust and King’s College London), S. Cortese (University of Southampton, Hampshire and Isle of Wight NHS Foundation Trust, the University of Bari “Aldo Moro” and the New York University Child Study Center) and A. Bellato (University of Southampton and the University of Nottingham in Malaysia). The study was published online on 9 October 2026 in the International Journal of Psychophysiology, the official journal of the International Organization of Psychophysiology. It is not a preprint but an article in a scientific journal.⁠¹

The team carried out a systematic review with meta-analysis: a study of studies. The team followed a plan registered in advance (PROSPERO CRD420251040957) and searched four large research databases: Embase, PsycINFO, PubMed and Web of Science. The researchers screened 9,713 search results, and 12 studies met the criteria. Five of these were randomised controlled trials whose results could be pooled. The other seven did not report figures that could be combined, so the team described them in words.⁠¹

Why this matters for you: the study suggests that how you feel and how your heart behaves are not two separate stories. When worrying eases, the body may follow, and one day that may show up in a measure you can take without filling in a single questionnaire. If you have ever lain awake with a busy mind and a pounding heart, that is good to know. The two are linked, and that link may be able to shift.

What heart rate variability really tells you

Heart rate variability is not a measure of speed. It is best seen as a measure of flexibility. Your heart rate tells you how many times your heart beats per minute. Heart rate variability looks inside that minute, at the small differences in time between one beat and the next.⁠⁷ Two people can have the same pulse and still have very different amounts of variation.

Two everyday moments make this concrete. In the first, you sit quietly and breathe slowly, and part of the variation moves along with your breathing. That breathing rhythm is the high-frequency band, and that band shows the calming branch of the nervous system at work.⁠⁷ In the second, you climb a flight of stairs, or read a message that unsettles you, and within moments your heart adjusts to the physical or mental demand.⁠⁷ A flexible system makes these shifts easy, and that flexibility is what the variation between beats captures.

Researchers don’t use a single number for this. They use several, and each measure looks at the variation from a different angle. SDNN is the total spread of the intervals between normal beats across a whole recording. RMSSD looks at the difference from each beat to the next and is regarded as a sign of vagus nerve activity. HF is the fast rhythm within the variation, the rhythm that follows your breathing.⁠⁷ LF is a slower rhythm, the LF/HF ratio compares the two, and the triangular index is another way of describing the total spread. This matters for the new review, because the measures did not all move in the same way.

Psychologists see this as important because heart rate variability has been put forward as a gauge of emotion regulation: how well you handle your feelings and bring yourself back into balance.⁠¹ Two researchers who were not involved in this review describe that interest.

Our studies show that awareness of one’s own emotions is an important protective factor against psychological strain.

Prof. Dr. Markus Quirin, Lehrstuhl für Persönlichkeitspsychologie und Motivation, PFH Private Hochschule Göttingen

Put simply, Quirin’s research, which is part of work on how the mind and the heart work together, finds that being aware of your own emotions is an important protection against mental strain.⁠⁸

HRV as a measure of brain health is something we are really very interested in.

Lori Cook, PhD, CCC-SLP, Director of Clinical Research, Center for BrainHealth, The University of Texas at Dallas

Cook’s centre studies heart rate variability as a window on the brain, the same window this review looks through.⁠⁹

What the review found, and in whom

The review looked at adults who had been diagnosed with low mood, anxiety or both, and who took part in cognitive behavioural therapy (CBT), one of the most widely used talking therapies for these complaints. Every included study measured heart rate variability at the start of the programme and again at the end.⁠¹

Of the 12 studies found, 5 randomised controlled trials could be pooled. In these trials, chance decided who had CBT and who went into a comparison group. Adults who had CBT showed a clearly greater rise in heart rate variability from start to finish than the comparison groups. That held for three measures: the high-frequency band that follows breathing (HF), the slower low-frequency band (LF) and the total spread of the intervals between beats (SDNN). On the other three measures, the LF/HF ratio, RMSSD and the triangular index, the review found no clear change.⁠¹

How many people took part is not stated in the abstract, the only part of the article we have read. The abstract also does not say how long the programmes lasted or what the comparison groups did. What the abstract does report is the size of the search: 9,713 search results screened, 12 studies included and 5 pooled.⁠¹

The authors read their own result with care. According to the authors, these are early signs that physical changes can go together with psychological improvement.⁠¹

What the review does not show

What this review does not show matters just as much as what it does show.

The study does not show a lasting change. It shows a greater rise in three measures over the course of a programme, in a small number of studies. Whether that rise lasted after the programme ended is not reported.

The study does not settle the question. Only 5 of the 12 studies could be pooled. The other 7 did not give figures that could be combined and are only described in words.⁠¹ That is a narrow basis for a firm conclusion.

The measures also contradict each other. The band linked to breathing went up, but RMSSD, which is also regarded as a sign of the calming branch of the nervous system,⁠⁷ did not clearly change. A clearer result would have shown both moving together.

The study does not show that heart rate variability can tell you whether a therapy works for you. According to the authors, more high-quality research is needed before heart rate variability can serve as a sign of how well CBT works, or as a way to predict who responds to it.⁠¹

Finally, the study tells us nothing about people without these symptoms. The review did not look at the general public but at adults who had been diagnosed with low mood or anxiety as a condition.

What you can do with this for your heart rate and fitness

This review is no reason to start or stop anything on your own. It is a reason to take the link between your head and your heart seriously. Here are three directions.

Take long-term stress seriously. If you have been troubled by worrying or tension for a long time, Thuisarts advises making an appointment with your GP or the practice nurse.⁠¹⁰ There you can ask what might help you.

See your body as part of the story. A full head is something you also feel in your chest. If your watch shows heart rate variability, do not treat that number as a verdict on one morning, but as one signal of how your body is holding up.

Keep moving. More than half of Dutch adults do not meet the Dutch Physical Activity Guidelines.⁠⁶ You can read what sitting still does to your body in our article on the effects of moving too little.

That leaves the question of how your own heart rate and fitness are doing today, and that is where each of these directions begins. The free BioProfile heart and vascular scan was made for that question: the scan gives you a first picture of where you stand, so you know your starting point.