Effects of diet and exercise training on neurovascular control during mental stress in obese women

Abstract

Since neurovascular control is altered in obese subjects, we hypothesized that weight loss by diet (D) or diet plus exercise training (D + ET) would improve neurovascular control during mental stress in obese women. In a study with a dietary reduction of 600 kcal/day with or without exercise training for 4 months, 53 obese women were subdivided in D (N = 22, 33 +/- 1 years, BMI 34 +/- 1 kg/m2), D + ET (N = 22, 33 +/- 1 years, BMI 33 +/- 1 kg/m2), and nonadherent (NA, N = 9, 35 +/- 2 years, BMI 33 +/- 1 kg/m2) groups. Muscle sympathetic nerve activity (MSNA) was measured by microneurography and forearm blood flow by venous occlusion plethysmography. Mental stress was elicited by a 3-min Stroop color word test. Weight loss was similar between D and D + ET groups (87 +/- 2 vs 79 +/- 2 and 85 +/- 2 vs 76 +/- 2 kg, respectively, P < 0.05) with a significant reduction in MSNA during mental stress (58 +/- 2 vs 50 +/- 2, P = 0.0001, and 59 +/- 3 vs 50 +/- 2 bursts/100 beats, P = 0.0001, respectively), although the magnitude of the response was unchanged. Forearm vascular conductance during mental stress was significantly increased only in D + ET (2.74 +/- 0.22 vs 3.52 +/- 0.19 units, P = 0.02). Weight loss reduces MSNA during mental stress in obese women. The increase in forearm vascular conductance after weight loss provides convincing evidence for D + ET interventions as a nonpharmacologic therapy of human obesity.

Effects of aerobic exercise training on sympathetic and renal responses to mental stress in humans

“…These findings are in agreement with previous studies examining catecholamine responses to mental stress and exercise training (1,4,5,30,31). Differences between our findings and Tonacio et al (34) are likely related to differences in subject demographics (obese women vs. healthy young men and women) and the experimental design (diet combined with aerobic exercise vs. only aerobic exercise). Nevertheless, our data indicate that aerobic exercise training does not alter sympathetic neural responses to mental stress in healthy men and women.…”

“…Values are reported as means Ϯ SE; n, number of subjects. stress were examined in obese women (34). Interestingly, diet and aerobic exercise not only reduced resting MSNA but also reduced MSNA responses to mental stress.…”

“…Therefore, the methods for reducing sympathetic neural responses to mental stress are clinically relevant. It was recently reported that diet combined with aerobic exercise training decreased muscle sympathetic nerve activity (MSNA) during resting conditions and mental stress (34). Unfortunately, this study examined only obese women, and it was unclear whether the reductions of MSNA were due to diet, exercise training, or the combination of diet and exercise.…”

Lifestyle Modification Is the First Line Treatment for Type 2 Diabetes

“…[6,88] Similarly, Straznicky et al [92] showed baseline sympathetic tone measured by muscle sympathetic nervous activity and nutritional responsiveness could predict the success of dietary weight loss, but not exercise, supporting the results including that the sympathetic nervous activity plays major mechanisms and roles on diet-induced weight loss pointed by Masuo, et al [5]. Ribeiro et al [93], Trombetta et al [94] and Tonacio et al [95] compared the effects of a low caloric diet and exercise on blood pressure lowering and forearm blood flow. They observed that only exercise, not diet, significantly increased forearm blood flow.…”

Treatments for Hypertension in Type 2 Diabetes-Non-Pharmacological and Pharmacological Measurements

“…Ribeiro et al [76], Trombetta et al [77] and Tonacio et al [78] compared the blood pressure lowering effects and forearm blood flow between a low caloric diet and exercise, and they observed that only exercise significantly increased forearm blood flow. Recently, Straznicky et al [79] and Masuo et al [80 have shown that a low caloric diet and exercise exert different effects on insulin resistance, the RAAS, and sympathetic nervous activity in obese hypertensive subjects, even though similar weight loss were observed.…”