How archery studies measure heart rate and HRV

Two measures from one signal

Studies draw two things from the heart's signal: heart rate, in beats per minute, and heart rate variability, or HRV, which looks at how much the interval between consecutive beats changes. Variability is summarised with time-domain indices such as RMSSD, or with frequency bands: the low band between 0.04 and 0.15 Hz, the high band between 0.15 and 0.40. The findings in archers, in chronological order, are in the line on the heartbeat and the shot; this page looks at how they were obtained.

The electrocardiogram, with electrodes on the chest, is the instrument of Keast and Elliott in 1990 and of Dal and colleagues in Turkey; the chest strap, usually a Polar, has been the most common instrument since 2008 and records only the timing of each beat, not the trace; optical sensors read the blood with light, at the finger, at the wrist or on the face in television footage. They are not equivalent. The 2017 methodological review that serves as the reference in psychophysiology recommends electrodes, because errors can be corrected by hand on the trace, notes that straps produce more artefacts from friction, and considers optical sensors reliable at rest but not under stress.

Where to put the sensor on an archer

When World Archery put archers' heart rates on television in 2012, nothing rigid was allowed on the chest, arms or hands, and the engineers settled for an optical sensor on the knee, without recording the signals. The Italian group behind the fibre-optic chest band first measured chest deformation: in four archers the upper right side of the ribcage deformed by up to 58% during the shot, too much for the sensors, which were placed elsewhere. Tested afterwards on nine volunteers, the band was off by 3.92% on average for heart rate read from the chest, but a single beat could be off by between minus 11.15 and plus 12.48 beats per minute, and the test was done with the breath held; worn by two archers at 70 m, it had no reference. The entry on the fibre-optic chest band stays at "reported".

The moment of measurement

"Heart rate while shooting" is not the same number in every study. In kyudo the measure was the peak of each shot, which came about ten seconds after release; in an Indonesian study it was the mean from the aiming position to release, 128.13 beats per minute in the men and 142.37 in the women; the first figure, from 1981, included the run to collect the arrows. The entry on heart rate while shooting therefore gives an order of magnitude.

The seconds around release need a dense, synchronised signal. Guru's group in India filmed the archer together with the strap's wristwatch and read heart rate off its display second by second, from five seconds before to five after release: 21,120 values in the 2025 study, with a monitor that the 2020 study described as validated at rest. The device in the 2008 Brazilian study averaged heart rate every five seconds, and an average like that cannot isolate the last second of aiming. The phase of the cardiac cycle, systole or diastole, needs the electrical trace, and the entry on release in diastole has a single study in support.

Then there is effort: Salazar measured 104.4 beats per minute while shooting and 103.0 while holding the bow at full draw without shooting, against 87.0 at rest, so comparing two archers, or two bows, also measures the cost of holding the draw.

In competition and on camera

In competition the strap is the usual tool: at an indoor competition in Greece arrow times were noted by hand to line the strap up with the shot, and before the 2024 Turkish indoor national championships archers were recorded for five seated minutes, with heart rate about 8 beats per minute above a training day. Such measurements support the entries stating that competition raises arousal and that it rises with what is at stake. The weak point is artefacts: without the trace only automatic filters can correct them, and the 2017 review does not consider that enough.

Contactless measurements are the least checked. An and colleagues estimated heart rate from facial colour in fifty ten-second clips of World Championship footage, never checking it against a heart rate monitor, and their correlation of -0.618 with score carries that limit.

Which variability index

The same review points to RMSSD as the estimate of vagal tone, how much the vagus nerve slows the heart: it is little affected by breathing and, in a study of 3,387 adults, two minutes were enough, as were several ten-second windows averaged together. The ratio between the low and high bands does not measure a sympathetic-parasympathetic balance, even though about 65% of articles still base their conclusions on it. The high band reflects vagal tone only with breathing between 9 and 24 breaths per minute, and archers control their breathing during the shot, which is how the authors of a 2020 Turkish study propose to explain their own results.

Duration matters too. The 1996 standards, restated in 2017, want a recording at least ten times the period of the lowest frequency studied, hence the five-minute reference and a one-minute minimum for the high band. The low band starts at 0.04 Hz, one oscillation every 25 seconds, and in the Greek study variability was calculated over the 20 seconds before each release: not even one full cycle fits, so low-band values and the ratio taken from those windows cannot be interpreted. RMSSD holds up better, but the archer is still at full draw, and during movement variability cannot be read as vagal tone.

The ratio also varies enormously from person to person: among the 22 novices in the virtual reality study its change from rest was -114.20 ± 476.17% with a real bow, so it could not separate shooting a bow from shooting in the headset, while RMSSD could. A Malaysian study of sedentary young men nonetheless read a rise in the ratio from 2.9 to 6.4 as an improvement, the very reading the review advises against. This is why the entry on which index to use is "transferred": the rule comes from psychophysiology, and nobody has compared the indices head to head in archers.

From one day to the next

In Keast's four archers, resting heart rate changed significantly between sessions one to three months apart; in the 32 Indian archers of 2025 it was lower in the second of two identical sessions, with score unchanged. Nobody has measured its reliability with a stated index: the entry on heart rate as an unstable measure says that it changes, not by how much. For variability the reference is endurance sport: in a 2013 review the correlation between changes in variability and in 10 km time was -0.76 using weekly averages and -0.17 using single-day values, and the entry on variability as a guide to training load stays "transferred".

What to check

• the instrument, and whether it was compared with a reference while the archer was shooting;
• which number: the peak, the mean during aiming, the value at release, an average every five seconds;
• how long the window is, where it falls relative to release, and whether it is long enough for the band used;
• whether breathing was controlled or at least measured, and whether the archer was still or at full draw;
• whether a resting measurement of the same archer, under stated conditions, serves as comparison;
• how many archers and how many arrows: for a medium effect the 2017 review puts the figure at 61 people, and many archery studies have fewer than twenty.

How design and sample are weighed is explained in How we read a study; what HRV means for an archer, in the article on HRV in archery.

@misc{campagna2026_enresearchmethodsmeasuringheartratehrv,
  author = {Campagna, Matteo},
  title = {How archery studies measure heart rate and HRV},
  year = {2026},
  howpublished = {Research, matteocampagna.com},
  url = {https://matteocampagna.com/en/research/methods/measuring-heart-rate-hrv},
  note = {accessed 2026-10-16}
}