Effects of Six Months Training on Physical Capacity and Metaboreflex Activity in Patients with Multiple Sclerosis

Abstract

Patients with multiple sclerosis (MS) have an increased systemic vascular resistance (SVR) response during the metaboreflex. It has been hypothesized that this is the consequence of a sedentary lifestyle secondary to MS. The purpose of this study was to discover whether a 6-month training program could reverse this hemodynamic dysregulation. Patients were randomly assigned to one of the following two groups: the intervention group (MSIT, n = 11), who followed an adapted training program; and the control group (MSCTL, n = 10), who continued with their sedentary lifestyle. Cardiovascular response during the metaboreflex was evaluated using the post-exercise muscle ischemia (PEMI) method and during a control exercise recovery (CER) test. The difference in hemodynamic variables such as stroke volume (SV), cardiac output (CO), and SVR between the PEMI and the CER tests was calculated to assess the metaboreflex response. Moreover, physical capacity was measured during a cardiopulmonary test till exhaustion. All tests were repeated after 3 and 6 months (T3 and T6, respectively) from the beginning of the study. The main result was that the MSIT group substantially improved parameters related to physical capacity (+5.31 ± 5.12 ml·min−1/kg in maximal oxygen uptake at T6) in comparison with the MSCTL group (−0.97 ± 4.89 ml·min−1/kg at T6; group effect: p = 0.0004). However, none of the hemodynamic variables changed in response to the metaboreflex activation. It was concluded that a 6-month period of adapted physical training was unable to reverse the hemodynamic dys-regulation in response to metaboreflex activation in these patients.

Systematic Review of Exercise Studies in Persons with Multiple Sclerosis: Exploring the Quality of Interventions According to the Principles of Exercise Training

“…1. Eighteen studies (34.6%) involved only aerobic exercises [5,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45], 16 studies (30.8%) involved only resistance exercise [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], and 18 studies (34.6%) involved a combination of aerobic and resistance exercise [62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77]…”

The Impact of Cardiovascular Diseases on Cardiovascular Regulation During Exercise in Humans: Studies on Metaboreflex Activation Elicited by the Post-exercise Muscle Ischemia Method

“…An excessive increase in SVR during metaboreflex was also recently discovered in a study of patients with multiple sclerosis [ 44 , 45 ]. The authors speculated that this exaggerated SVR response was probably the consequence of the physical deconditioning of these patients, which caused a shift in fibre type composition from type I to a greater proportion of type II fibres, thereby inducing a more pronounced production of metabolic by-products in the muscle, which in turn caused a more robust metaboreflex engagement.…”

“…The authors speculated that this exaggerated SVR response was probably the consequence of the physical deconditioning of these patients, which caused a shift in fibre type composition from type I to a greater proportion of type II fibres, thereby inducing a more pronounced production of metabolic by-products in the muscle, which in turn caused a more robust metaboreflex engagement. However, this hemodynamic scenario did not change after a 6-month programme of physical intervention which was able to increase physical capacity in these patients [ 45 ]. This finding seems to contradict the concept that deconditioning is the main cause of the excessive vasoconstriction in the arteriolar bed of patients suffering from multiple sclerosis.…”

Metaboreflex-mediated hemodynamic abnormalities in individuals with coronary artery disease without overt signs or symptoms of heart failure

“…Thus, the total recovery lasted 6 min. This protocol has been used several times in the past in similar experimental settings to study hemodynamic consequences of metaboreflex recruitment in both healthy subjects and patients (14,15,29,30,33,49,50).…”

“…Hemodynamic assessment. Throughout the PEMI and CER tests, hemodynamics were measured using the transthoracic impedance cardiography method, which has been previously used in similar experimental settings dealing with the metaboreflex activation in both healthy subjects and disease states (14,16,18,29,32,33,49,50). The impedance method allows for noninvasive calculation of SV on the basis of the Sramek-Bernstein equation (5).…”