RESUMEN
Young individuals with post-traumatic stress disorder (PTSD) display peripheral vascular and autonomic nervous system dysfunction, two factors potentially stemming from a redox imbalance. It is currently unclear if these aforementioned factors, observed at rest, alter peripheral haemodynamic responses to exercise in this population. This study examined haemodynamic responses to handgrip exercise in young individuals with PTSD following acute antioxidant (AO) supplementation. Thirteen young individuals with PTSD (age 23 ± 3 years), and 13 age- and sex-matched controls (CTRL) participated in the study. Exercise-induced changes to arm blood flow (BF), mean arterial pressure (MAP) and vascular conductance (VC) were evaluated across two workloads of rhythmic handgrip exercise (3 and 6 kg). The PTSD group participated in two visits, consuming either a placebo (PL) or AO prior to their visits. The PTSD group demonstrated significantly lower VC (P = 0.04) across all exercise workloads (vs. CTRL), which was significantly improved following AO supplementation. In the PTSD group, AO supplementation improved VC in participants possessing the lowest VC responses to handgrip exercise, with AO supplementation significantly improving VC responses (3 and 6 kg: P < 0.01) by blunting elevated exercise-induced MAP responses (3 kg: P = 0.01; 6 kg: P < 0.01). Lower VC responses during handgrip exercise were improved following AO supplementation in young individuals with PTSD. AO supplementation was associated with a blunting of exercise-induced MAP responses in individuals with PTSD displaying elevated MAP responses. This study revealed that young individuals with PTSD exhibit abnormal, peripherally mediated exercise responses that may be linked to a redox imbalance.
Asunto(s)
Antioxidantes , Suplementos Dietéticos , Ejercicio Físico , Fuerza de la Mano , Trastornos por Estrés Postraumático , Humanos , Fuerza de la Mano/fisiología , Antioxidantes/administración & dosificación , Masculino , Femenino , Adulto Joven , Trastornos por Estrés Postraumático/fisiopatología , Ejercicio Físico/fisiología , Adulto , Hemodinámica/efectos de los fármacos , Hemodinámica/fisiología , Presión Sanguínea/fisiología , Presión Sanguínea/efectos de los fármacos , Flujo Sanguíneo Regional/fisiología , Flujo Sanguíneo Regional/efectos de los fármacosRESUMEN
PURPOSE: Adequate, robust vascular responses to passive and active movement represent two distinct components linked to normal, healthy cardiovascular function. Currently, limited research exists determining if these vascular responses are altered in premenopausal females (PMF) when compared across sex or menstrual cycle phase. METHODS: Vascular responses to passive leg movement (PLM) and handgrip (HG) exercise were assessed in PMF ( n = 21) and age-matched men ( n = 21). A subset of PMF subjects ( n = 11) completed both assessments during the early and late follicular phase of their menstrual cycle. Microvascular function was assessed during PLM via changes in leg blood flow, and during HG exercise, via steady-state arm vascular conductance. Macrovascular (brachial artery [BA]) function was assessed during HG exercise via BA dilation responses as well as BA shear rate-dilation slopes. RESULTS: Leg microvascular function, determined by PLM, was not different between sexes or across menstrual cycle phase. However, arm microvascular function, demonstrated by arm vascular conductance, was lower in PMF compared with men at rest and during HG exercise. Macrovascular function was not different between sexes or across menstrual cycle phase. CONCLUSIONS: This study identified similar vascular function across sex and menstrual cycle phase seen in microvasculature of the leg and macrovascular (BA) of the arm. Although arm microvascular function was unaltered by menstrual cycle phase in PMF, it was revealed to be significantly lower when compared with age-matched men highlighting a sex difference in vascular/blood flow regulation during small muscle mass exercise.
Asunto(s)
Fuerza de la Mano , Movimiento , Humanos , Masculino , Femenino , Fuerza de la Mano/fisiología , Arteria Braquial/fisiología , Hemodinámica , Ciclo Menstrual , Flujo Sanguíneo Regional/fisiología , Vasodilatación/fisiologíaRESUMEN
PURPOSE: Young non-Hispanic black (BL) males have displayed lower blood flow (BF) and vascular conductance (VC), but intact functional sympatholysis, during upper limb exercise when compared to non-Hispanic white (WH) males. This study sought to explore if similar differences were also present in the lower limbs. METHODS: Thirteen young BL males and thirteen WH males completed one visit comprised of rhythmic lower limb (plantar flexion) exercise as well as upper limb (handgrip) exercise for a limb-specific comparison. Limb BF, mean arterial pressure (MAP), and VC were evaluated at three submaximal workloads (8, 16, and 24 kg). To determine potential limb differences in functional sympatholysis, the impact of sympathetic nervous system activation (via cold-pressor test (CPT)) was evaluated at rest and during steady state exercise (30 % of maximal voluntary contraction) on a subsequent visit. RESULTS: MAP responses to lower and upper limb exercise were elevated in young BL males (vs WH males), resulting in significantly lower VC responses in the upper limb, but not the lower limb. Further, BL males, when compared to WH males, revealed no differences in functional sympatholysis, evident by similar responses in both the exercising leg and arm VC during CPT. CONCLUSION: The findings of the current study indicate that although elevated MAP responses were observed during both lower and upper limb exercise in young BL males, vascular conductance was only hindered in the upper limbs. This may potentially highlight enhanced compensatory mechanisms in the lower limb (vs upper limb) to maintain perfusion in young BL males.
Asunto(s)
Fuerza de la Mano , Simpaticolíticos , Masculino , Humanos , Fuerza de la Mano/fisiología , Flujo Sanguíneo Regional , Ejercicio Físico/fisiología , Extremidad Inferior , Presión Sanguínea , Músculo EsqueléticoRESUMEN
This study sought to determine if high sodium (HS) intake in salt resistant (SR) individuals attenuates upper limb arterial dilation in response to reactive (occlusion) and active (exercise) hyperemia, two stimuli with varying vasodilatory mechanisms, and the role of oxidative stress in this response. Ten young, SR participants (9 males, 1 female) consumed a 7-day HS (6,900 mg/day) and a 7-day recommended sodium intake (RI: 2,300 mg/day) diet in a randomized order. On the last day of each diet, brachial artery (BA) function was evaluated via reactive (RH-FMD: 5 min of cuff occlusion) and active [handgrip (HG) exercise] hyperemia after consumption of both placebo (PL) and antioxidants (AO). The HS diet significantly elevated sodium excretion (P < 0.05), but mean arterial blood pressure was unchanged. During the PL condition, the HS diet significantly reduced RH-FMD when compared with RI diet (P = 0.01), but this reduction was significantly restored (P = 0.01) when supplemented with AO (HS + PL: 5.9 ± 3.4; HS + AO: 8.2 ± 2.7; RI + PL: 8.9 ± 4.7; RI + AO: 7.0 ± 2.1%). BA shear-to-dilation slopes, evaluated across all HG exercise workloads, were not significantly different across sodium intervention or AO supplementation. In SR individuals, HS intake impaired BA function when assessed via RH-FMD, but was restored with acute AO consumption suggesting oxidative stress as a contributor to this dysfunction. However, exercise-induced BA dilation was unaltered, potentially implicating an inability of HS intake to influence the mechanisms responsible for effectively maintaining skeletal muscle perfusion during exercise.NEW & NOTEWORTHY This study examined if high sodium (HS) intake in salt resistant (SR) individuals attenuates brachial artery (BA) flow-mediated dilation in response to reactive (occlusion) and active (exercise) hyperemia. In SR individuals, HS intake impaired reactive hyperemia-induced BA dilation, but not exercise-induced BA dilation. This finding suggests that although brachial artery nitric oxide bioavailability may be reduced following HS intake, the redundant mechanisms associated with adequate upper limb blood flow regulation during exercise are maintained.
Asunto(s)
Hiperemia , Sodio en la Dieta , Femenino , Humanos , Masculino , Velocidad del Flujo Sanguíneo/fisiología , Arteria Braquial/fisiología , Dilatación , Endotelio Vascular/fisiología , Fuerza de la Mano/fisiología , Flujo Sanguíneo Regional/fisiología , Sodio , Extremidad Superior , Vasodilatación/fisiologíaRESUMEN
Posttraumatic stress disorder (PTSD) has been associated with an increase in risk of cardiovascular disease (CVD). The goal of this study was to determine if peripheral vascular dysfunction, a precursor to CVD, was present in young adults with PTSD, and if an acute antioxidant (AO) supplementation could modify this potential PTSD-induced vascular dysfunction. Thirteen individuals with PTSD were recruited for this investigation and were compared with 35 age- and sex-matched controls (CTRL). The PTSD group participated in two visits, consuming either a placebo (PTSD-PL) or antioxidants (PTSD-AO; vitamins C and E; α-lipoic acid) before their visits, whereas the CTRL subjects only participated in one visit. Upper and lower limb vascular functions were assessed via flow-mediated dilation and passive leg movement technique. Heart rate variability was utilized to assess autonomic nervous system modulation. The PTSD-PL condition, when compared with the CTRL group, reported lower arm and leg microvascular function as well as sympathetic nervous system (SNS) predominance. After acute AO supplementation, arm, but not leg, microvascular function was improved and SNS predominance was lowered to which the prior difference between PTSD group and CTRL was no longer significant. Young individuals with PTSD demonstrated lower arm and leg microvascular function as well as greater SNS predominance when compared with age- and sex-matched controls. Furthermore, this lower vascular/autonomic function was augmented by an acute AO supplementation to the level of the healthy controls, potentially implicating oxidative stress as a contributor to this blunted vascular/autonomic function.
Asunto(s)
Ácido Ascórbico/farmacología , Sistema Nervioso Autónomo/efectos de los fármacos , Trastornos por Estrés Postraumático/tratamiento farmacológico , Ácido Tióctico/farmacología , Vitamina E/farmacología , Adulto , Antioxidantes/administración & dosificación , Antioxidantes/farmacología , Ácido Ascórbico/administración & dosificación , Presión Sanguínea , Estudios de Casos y Controles , Quimioterapia Combinada , Femenino , Humanos , Masculino , Ácido Tióctico/administración & dosificación , Vitamina E/administración & dosificación , Adulto JovenRESUMEN
PURPOSE: Lower limb microvascular dysfunction resulting from prolonged sitting (PS) bouts has been revealed to occur independent of sex. Although acute antioxidant supplementation has been reported to blunt conduit artery dysfunction following PS in young males, it is unknown if this protective effect extends to the microvasculature or is relevant in young females, who possess intrinsic vascular protective mechanisms specific to antioxidant defense. Therefore, this study employed an acute antioxidant supplementation to further examine sex differences during PS with a specific focus on microvascular function. METHODS: On two separate visits, 14 females (23 ± 3 years) and 12 males (25 ± 4 years) had leg microvascular function (LMVF) assessed (via the passive leg movement technique) before and after 1.5 h of sitting. Prior to each visit, one gram of vitamin C (VC) or placebo (PL) was consumed. RESULTS: PS significantly reduced LMVF [PL: (M: -34 ± 20; F: -23 ± 18%; p < 0.01) independent of sex (p = 0.7)], but the VC condition only blunted this reduction in males (VC: -3 ± 20%; p < 0.01), but not females (VC: -18 ± 25%; p = 0.5). CONCLUSION: Young males and females reported similar reductions LMVF following PS, but only the young males reported a preservation of LMVF following the VC supplementation. This finding in young females was highlighted by substantial variability in LMVF measures in response to the VC condition that was unrelated to changes in the potential contributors to sitting-induced reductions in LMVF (e.g. lower limb venous pooling, reduced arterial shear rate). NEW AND NOTEWORTHY: In this study, we employed an acute Vitamin C (VC) supplementation to examine sex differences in leg microvascular function (LMVF) following a bout of prolonged sitting. This study revealed that prolonged sitting reduced LMVF independent of sex, but only young males reported an attenuation to this lowered LMVF following VC supplementation. The young females revealed substantial variability in sitting-induced changes to LMVF that could not be explained by the potential contributors to sitting-induced reductions in LMVF (e.g. lower limb venous pooling, reduced arterial shear rate).
Asunto(s)
Antioxidantes/administración & dosificación , Ácido Ascórbico/administración & dosificación , Extremidad Inferior/irrigación sanguínea , Microcirculación/efectos de los fármacos , Microvasos/efectos de los fármacos , Sedestación , Adulto , Femenino , Humanos , Masculino , Microvasos/fisiopatología , Distribución Aleatoria , Factores Sexuales , Factores de Tiempo , Adulto JovenRESUMEN
NEW FINDINGS: What is the central question of this study? We sought to investigate whether young adults reporting low sleep quality possessed lower vascular function and altered autonomic nervous system modulation when compared with young adults reporting high sleep quality. What is the main finding and its importance? The study revealed that in young adults reporting low sleep quality, neither vascular nor autonomic function was significantly different when compared with young adults reporting high sleep quality. These findings suggest that young adults are either not substantially impacted by or can adequately adapt to the negative consequences commonly associated with poor sleep. ABSTRACT: The aim of the study was to investigate whether young adults reporting low sleep quality also possessed lower vascular function, potentially stemming from altered autonomic nervous system modulation, when compared with young adults reporting high sleep quality. Thirty-one healthy young adults (age 24 ± 4 years) underwent a 7 night sleep assessment (Actigraph GT3X accelerometer). After the sleep assessment, subjects meeting specific criteria were separated into high (HSE; ≥85%; n = 11; eight men and three women) and low (LSE; <80%; n = 11; nine men and two women) sleep efficiency groups. Peripheral vascular function was assessed in the upper and lower limb, using the flow-mediated dilatation technique in the arm (brachial artery) and leg (superficial femoral artery). Heart rate variability was evaluated during 5 min of rest and used frequency parameters reflective of parasympathetic and/or sympathetic nervous system modulation (high- and low-frequency parameters). By experimental design, significant differences in sleep quality between groups were reported, with the LSE group exhibiting a longer time awake after sleep onset, higher number of awakenings and longer average time per awakening when compared with the HSE group. Despite these differences in sleep quality, no significant differences in upper and lower limb vascular function and heart rate variability measures were revealed when comparing the LSE and HSE groups. Additionally, in all subjects (n = 31), no correlations between sleep efficiency and vascular function/autonomic modulation were revealed. This study revealed that low sleep quality does not impact upper or lower limb vascular function or autonomic nervous system modulation in young adults.
Asunto(s)
Sistema Nervioso Autónomo/fisiología , Extremidad Inferior/fisiología , Sueño/fisiología , Adulto , Presión Sanguínea , Ejercicio Físico , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Flujo Sanguíneo Regional , Sistema Nervioso Simpático/fisiología , Adulto JovenRESUMEN
This study examined if the degree of aerobic training protects against the lower limb vascular dysfunction associated with a prolonged sitting bout. Ten young, aerobically trained (AT) and 10 young, untrained (UT) individuals completed a prolonged (3 h) sitting bout. Leg vascular function was measured prior to and at 1.5 and 3 h into the prolonged sitting bout using the passive leg movement (PLM) technique. PLM-induced hyperemia was significantly reduced from baseline at 1.5 and 3 h into the prolonged sitting bout in both groups when evaluated as peak change in leg blood flow from baseline (Δ LBF) (UT: 956 ± 140, 586 ± 80, and 599 ± 96 mL·min-1 at baseline, 1.5 h, and 3 h, respectively; AT: 955 ± 183, 789 ± 193, and 712 ± 131 mL·min-1 at baseline, 1.5 h, and 3 h, respectively) and LBF area under the curve (UT: 283 ± 73, 134 ± 31, and 164 ± 42 mL·min-1 at baseline, 1.5 h, and 3 h, respectively; AT: 336 ± 86, 242 ± 86, and 245 ± 73 mL·min-1 at baseline, 1.5 h, and 3 h, respectively), but no significant differences between groups were revealed. No significant correlations were observed when examining the relationship between maximal oxygen uptake (relative and absolute) and reductions in leg vascular function at 1.5 and 3 h into the prolonged sitting bout. This study revealed that aerobic training did not provide a protective effect against prolonged sitting-induced lower limb vascular dysfunction and further highlights the importance of reducing excessive sitting in all populations.