Fluctuations in cardiac stroke volume during rowing

Abstract

Preload to the heart may be limited during rowing because both blood pressure and central venous pressure increase when force is applied to the oar. Considering that only the recovery phase of the rowing stroke allows for unhindered venous return, rowing may induce large fluctuations in stroke volume (SV). Thus, the purpose of this study was to evaluate SV continuously during the rowing stroke. Eight nationally competitive oarsmen (mean ± standard deviation: age 21 ± 2 years, height 190 ± 9 cm, and weight 90 ± 10 kg) rowed on an ergometer at a targeted heart rate of 130 and 160 beats per minute. SV was derived from arterial pressure waveform by pulse contour analysis, while ventilation and force on the handle were measured. Mean arterial pressure was elevated during the stroke at both work rates (to 133 ± 10 [P < .001] and 145 ± 11 mm Hg [P = .024], respectively). Also, SV fluctuated markedly during the stroke with deviations being largest at the higher work rate. Thus, SV decreased by 27 ± 10% (31 ± 11 mL) at the beginning of the stroke and increased by 25 ± 9% (28 ± 10 mL) in the recovery (P = .013), while breathing was entrained with one breath during the drive of the stroke and one prior to the next stroke. These observations indicate that during rowing cardiac output depends critically on SV surges during the recovery phase of the stroke.

Influence of breathing on variation in cardiac stroke volume at the onset of cycling

“…The results confirmed that variation in SV is similar at rest and during exercise (Sejersen et al 2021). The new finding is that at the onset of cycling exercise (i.e., within 5 s) an approximately 2.5-fold increase in SVV developed, related to variation in the ventilatory but not in the hemodynamic variables.…”

“…3). This variation in SV does not manifest at rest or when exercise is ongoing and ventilation likely becomes entrained to movement of the legs as demonstrated during rowing (Sejersen et al 2021;Steinacker et al 1993). In summary, variation in SV at the onset of exercise is influenced by the breathing pattern dominated by Rf may to stabilize the trunk and at the same time maintains blood pressure despite a rapid decrease in TPR.…”

“…We take it that about 5 s fluctuations in SV is of little consequence for over-all regulation of the circulation during maintained exercise, e.g., in regard to release of atrial natriuretic peptide (ANP) (e.g., Yoshiga et al 2019) and thereby diuresis. The continuous fluctuation in SV elicited during repeated relative slow contractions as during repeated weightlifting, canoeing, and rowing (Sejersen et al 2021) seems important for the increase in plasma ANP. At least during rowing the increase in ANP is larger than during running for a given increase in CO (Yoshiga et al 2019).…”

“…In contrast to rowing, cycling exercise is not associated with a larger SVV than at rest (Sejersen et al 2021). Yet, we consider that initiation of many, if not all types of wholebody dynamic exercise is accompanied by a Valsalva-like maneuver.…”

“…During submaximal ergometer rowing an influence of ventilation on stroke volume (SV) was demonstrated with a ~ 25% decrease in SV during the catch followed by a ~ 25% increase in the recovery compared to the average SV value (Sejersen et al 2021). The SV variation (SVV) during rowing is associated with a Valsalva-like maneuver by a breath hold or exhaling through a partially closed glottis at the catch, aimed to stabilize the trunk.…”