Biomedical subjects

Nancy Rodriguez

Publications and source records attributed to Nancy Rodriguez.

3 recordsLinked to original sources

PubMed2007

Dietary calcium intake and renin angiotensin system polymorphisms alter the blood pressure response to aerobic exercise: a randomized control design.

BACKGROUND: Dietary calcium intake and the renin angiotensin system (RAS) regulate blood pressure (BP) by modulating calcium homeostasis. Despite similar BP regulatory effects, the influence of dietary calcium intake alone and combined with RAS polymorphisms on the BP response following acute aerobic exercise (i.e., postexercise hypotension) has not been studied. Thus, we examined the effect of dietary calcium intake and selected RAS polymorphisms on postexercise hypotension. METHODS: Subjects were men (n = 50, 43.8 +/- 1.3 yr) with high BP (145.3 +/- 1.5/85.9 +/- 1.1 mm Hg). They completed three experiments: non-exercise control and two cycle bouts at 40% and 60% of maximal oxygen consumption (VO2max). Subjects provided 3 d food records on five protocol-specific occasions. Dietary calcium intake was averaged and categorized as low (<880 mg/d = LowCa) or high (> or = 880 mg/d = HighCa). RAS polymorphisms (angiotensin converting enzyme insertion/deletion, ACE I/D; angiotensin II type 1 receptor, AT1R A/C) were analyzed with molecular methods. Genotypes were reduced from three to two: ACE II/ID and ACE DD; or AT1R AA and AT1R CC/AC. Repeated measure ANCOVA tested if BP differed among experiments, dietary calcium intake level and RAS polymorphisms. RESULTS: Systolic BP (SBP) decreased 6 mm Hg after 40% and 60% VO2max compared to non-exercise control for 10 h with LowCa (p < 0.01), but not with HighCa (p > or = 0.05). Under these conditions, diastolic BP (DBP) did not differ between dietary calcium intake levels (p > or = 0.05). With LowCa, SBP decreased after 60% VO2max versus non-exercise control for 10 h among ACE II/ID (6 mm Hg) and AT1R AA (8 mm Hg); and by 8 mm Hg after 40% VO2max among ACE DD and AT1R CC/CA (p < 0.01). With HighCa, SBP (8 mm Hg) and DBP (4 mm Hg) decreased after 60% VO2max compared to non-exercise control for 10 h (p < 0.05), but not after 40% VO2max (p > or = 0.05). CONCLUSION: SBP decreased after exercise compared to non-exercise control among men with low but not high dietary calcium intake. Dietary calcium intake interacted with the ACE I/D and AT1R A/C polymorphisms to further modulate postexercise hypotension. Interactions among dietary calcium intake, exercise intensity and RAS polymorphisms account for some of the variability in the BP response to exercise.

Journal Article↗

PubMed2004

Exercise intensity alters postexercise hypotension.

OBJECTIVE: Blood pressure (BP) is immediately lowered after a session of dynamic exercise, e.g. postexercise hypotension (PEH). The optimal exercise intensity needed to evoke PEH has not been established. We examined the effect of light (LITE) and moderate (MOD) exercise intensity on PEH. DESIGN: Subjects were 49 men (mean +/- SEM, 43.8 +/- 1.4 years) with high normal to stage 1 hypertension (145.0 +/- 1.5/85.8 +/- 1.1 mmHg). Men randomly completed three blinded experiments: a control session and two cycle exercise bouts, one at 40% (LITE) and the other at 60% (MOD) of maximal oxygen consumption. METHODS: Experiments began with a baseline period and were conducted at the same time of day and separated by >/= 2 days. Subjects wore an ambulatory BP monitor after the experiments. Repeated measure analysis of variance (ANOVA) tested if BP and heart rate differed over time and between experimental conditions. Multivariate regression tested factors related to the BP response. RESULTS: For 9 h after all experiments, average awake systolic blood pressure (SBP) increased and diastolic blood pressure (DBP) decreased compared with baseline (P < 0.001). Average awake SBP increased up to 6.9 mmHg less (P < 0.001) and DBP decreased 2.6 mmHg more (P < 0.05) after exercise versus control. For 5 h, PEH was greater after MOD; but over the course of 9 h, LITE was as effective as MOD in eliciting PEH. Baseline BP was the primary factor explaining the BP response (beta = -0.434 to -0.718, r = 0.096-0.295). CONCLUSIONS: LITE and MOD evoked PEH throughout the daytime hours. Lower intensity dynamic exercise such as walking, contributes to BP control in men with hypertension.

Adult↗

PubMed2002

Effects of resistance training on protein utilization in healthy children.

PURPOSE: Public health initiatives promote increased physical activity in children. More specifically, resistance training has recently received attention as an important component of youth fitness programs. The study examined the effect of this mode of exercise on protein utilization in young boys and girls. METHODS: Healthy children (N = 11, 8.6 +/- 1.1 yr, 33.7 +/- 9.4 kg, 131 +/- 9.6 cm, BMI = 19.1 +/- 3.4) participated in a supervised resistance-training program 2 times.wk-1 for 6 wk. 15N glycine methodology was used to assess nitrogen flux (Q), protein synthesis (PS), protein breakdown (PB), and net turnover ([NET] = PS - PB) before (PRE) and after (POST) resistance training. Percent body fat (%BF), fat-free mass (FFM), fat mass (FM), and energy and protein intakes were also determined. PRE/POST measurements of 1RM for the chest press and leg extension were used to examine strength gains. RESULTS: Gains associated with the chest press and leg extension were 10% and 75% (P < 0.001), respectively. Significant increases (P < 0.05) were noted for weight, height, FFM, and FM. Energy and protein intake remained constant. Significant decreases (PRE vs POST) were observed for Q (1.22 +/- 0.1 vs 0.75 +/- 0.05 gN.kg-1.d-1, P < 0.001), PS (6.48 +/- 0.47 vs 3.55 +/- 0.30 g.kg-1.d-1, P < 0.001), and PB (5.24 +/- 0.41 vs 2.96 +/- 0.30 g.kg-1.d-1, P < 0.01) after 6 wk of resistance training. NET was also reduced (P = 0.07, 1.24 +/- 0.31 vs 0.59 +/- 0.20 g.kg-1.d-1). CONCLUSIONS: Resistance training resulted in a downregulation in protein metabolism, which may be energy based. Future studies are needed to clarify energy, as well as protein, needs in young children participating in this form of exercise.

Anthropometry↗