Calf venous volume during stand‐test after a 90‐day bed‐rest study with or without exercise countermeasure

Abstract

The objectives to determine both the contribution to orthostatic intolerance (OI) of calf venous volume during a stand-test, and the effects of a combined eccentric-concentric resistance exercise countermeasure on both vein response to orthostatic test and OI, after 90-day head-down tilt bed-rest (HDT). The subjects consisted of a control group (Co-gr, n = 9) and an exercise countermeasure group (CM-gr, n = 9). Calf volume and vein cross-sectional area (CSA) were assessed by plethysmography and echography during pre-and post-HDT stand-tests. From supine to standing (post-HDT), the tibial and gastronemius vein CSA increased significantly in intolerant subjects (tibial vein, +122% from pre-HDT; gastronemius veins, +145%; P < 0.05) whereas it did not in tolerant subjects. Intolerant subjects tended to have a higher increase in calf filling volume than tolerant subjects, in both sitting and standing positions. The countermeasure did not reduce OI. Absolute calf volume decreased similarly in both groups. Tibial and gastrocnemius vein CSA at rest did not change during HDT in either group. During the post-HDT stand-test, the calf filling volume increased more in the CM-gr than in the Co-gr both in the sitting (+1.3 ± 5.1%, vs. -7.3 ± 4.3%; P < 0.05) and the standing positions (+56.1 ± 23.7% vs. +1.6 ± 9.6%; P < 0.05). The volume ejected by the muscle venous pump increased only in the CM-gr (+38.3 ± 21.8%). This study showed that intolerant subjects had a higher increase in vein CSA in the standing position and a tendency to present a higher calf filling volume in the sitting and standing positions. It also showed that a combined eccentric-concentric resistance exercise countermeasure had no effects on either post-HDT OI or on the venous parameters related to it.

The effect of bed rest and an exercise countermeasure on leg venous function

“…Because the popliteal vein is located isolated in the popliteal space and not directly surrounded by muscles, venous compliance was not severely influenced by the decrease in muscle mass. A similar finding was reported by Belin de Chantemele et al (2004), who found no relationship between calf muscle atrophy and calf vein deconditioning. Alternative factors that may contribute to the changes in venous compliance are alterations in the venous vessel wall Louisy et al 1997;Monahan et al 2001) or gravitational gradients within the circulation .…”

“…However, an efficient countermeasure effect of this physical exercise during deconditioning on the venous vascular system is not demonstrated yet. Resistive exercise failed to affect the response of tibial and gastrocnemial vein diameter to bed rest (Belin de Chantemele et al 2004). If vein diameter accounts for venous capacitance and compliance, and resistive vibration exercise is no effective countermeasure on a relatively spacious vein (not directly surrounded by muscle mass), it is unlikely that exercise has a protective effect on venous function.…”

“…Both venous capacitance and compliance are major determinants in the vital functions of the venous system, and a numerous amount of studies have been performed to specify their role in orthostatic intolerance after bed rest and space flight in humans. To study the effect of physical deconditioning on the venous vascular system, several human deconditioning models have been used, such as leg immobilisation (Bleeker et al 2005a), space flight (Arbeille et al 2001;Fomina and Kotovskaia 2005;Watenpaugh et al 2001), bed rest (Arbeille et al 1999(Arbeille et al , 2001Belin de Chantemele et al 2004;Bleeker et al 2005b;Bonde-Petersen et al 1994;Buckey et al 1992;Christ et al 2001;Convertino et al 1989;Louisy et al 1997;Melchior and Fortney 1993;Xiao et al 2005) and spinal-cord injury (Frieden et al 1987;Hopman et al 1994;Wecht et al 2000). Sparse data on venous diameter show a reduction in cross-sectional area of femoral venous diameter after bed rest (Arbeille et al 1999(Arbeille et al , 2001), but no change in tibial and gastrocnemial venous diameter (Belin de Chantemele et al 2004).…”

“…the popliteal vein (De Groot et al 2005). Transverse echographic views were used before for measuring cross-sectional areas of the deep and muscular vein in the calf (Belin de Chantemele et al 2004). Ultrasound and plethysmography measurements of venous compliance correlated significantly (De Groot et al 2005) and supported the observation by Buckey et al (1988), who reported that most volume changes at different venous occlusion pressures are attributable to deep venous filling which is represented by the popliteal vein.…”

WISE-2005: effect of aerobic and resistive exercises on orthostatic tolerance during 60 days bed rest in women

“…Several factors contribute to orthostatic intolerance: moderate hypovolemia (Buckey et al 1996;Custaud et al 2002), decreased stroke volume (Buckey et al 1996), myocardial atrophy (Levine et al 1997), reduced baroreXex sensitivity (Sigaudo-Roussel et al 2002) and increased distensibility of lower extremity blood vessels (Convertino et al 1989;Belin de Chantemele et al 2004b). Furthermore, females have a lower orthostatic tolerance than males (Convertino 1998;Fu et al 2004).…”