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Augmented Skeletal Muscle Metaboreflex Activation in Patients with Type 2 Diabetes Mellitus
Author(s) -
Holwerda Seth,
Restaino Robert,
Fisher James,
Fadel Paul
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.827.7
Subject(s) - medicine , type 2 diabetes mellitus , diabetes mellitus , skeletal muscle , cardiology , type 2 diabetes , endocrinology
Previous reports demonstrate augmented blood pressure responses to exercise in patients with type 2 diabetes mellitus (T2D). However, the underlying neural mechanisms involved remain unknown. We tested the hypothesis that T2D patients would exhibit an augmented activation of the muscle metaboreflex, which contributes to greater pressor and sympathetic responses during exercise. Mean arterial pressure (MAP), heart rate (HR), and muscle sympathetic nerve activity (MSNA) were measured in T2D patients (n=13) and age‐ and sex‐matched healthy controls (CON, n=6) during static handgrip performed at 30 and 40% maximal voluntary contraction (MVC) followed by a period of postexercise ischemia (PEI) to isolate the muscle metaboreflex. Peak 30s average increases in MAP from baseline were augmented in T2D patients compared to controls during both 30 and 40% MVC handgrip (40%: T2D, +32 ± 3 vs. CON, +20 ± 5 mmHg, P<0.05), and these differences were maintained during PEI (40%: T2D, +29 ± 4 vs. CON, +15 ± 4 mmHg, P<0.05). Similarly, peak 30s average increases in MSNA from baseline were augmented in T2D subjects compared to controls during both 30 and 40% MVC handgrip (40%: T2D, +190 ± 38 vs. CON, +87 ± 51 AU·min, P<0.05), and these differences were also maintained during PEI (40%: T2D, +180 ± 41 vs. CON, +29 ± 7 AU·min, P<0.05). HR increased similarly in both groups during handgrip and returned toward baseline with PEI. These preliminary findings suggest T2D patients exhibit augmented pressor and sympathetic responses to handgrip exercise, which are in part attributable to heightened metaboreflex activation.