Biomedical subjects

Styliani Goulopoulou

Publications and source records attributed to Styliani Goulopoulou.

8 recordsLinked to original sources

PubMed2006

Heart rate variability during recovery from a Wingate test in adolescent males.

PURPOSE: To evaluate the effect of maturity status on the autonomic nervous system at rest and recovery after short-term, high-intensity exercise in adolescents. METHODS: A biological maturity age was estimated in 27 males by calculating the years from peak height velocity (PHV) using a multiple regression equation. Subjects were divided into two groups: pre-PHV (years from PHV < 0.49), N = 14, mean age = 12.29 +/- 0.91 yr; post-PHV (years from PHV > 0.5, N = 13, mean age = 15.12 +/-0.76 yr). HR variability was used to evaluate autonomic function. ECG tracings were collected during 5 min at rest and recovery after a Wingate test and were analyzed in the frequency domain (low-frequency (LF), high-frequency (HF), LF/HF, total power (TP)). Data are presented as natural logarithms (LN). RESULTS: Changes in HR from HR(peak) during exercise to HR measured at minute 4 after exercise ([DELTA]HR4) were significantly greater in the pre-PHV group (84.31 +/-17.58 bpm) compared with the post-PHV group (69.42 +/-17.63 bpm). There were no significant differences in resting HR variability between pre- and post-PHV groups (P > 0.05). Significant group x time interactions were found for LF(LN) (ms(2)) and TP(LN) (ms(2)) measured during recovery (P < 0.05). Post hoc tests showed that the pre-PHV group had significantly higher postexercise LF(LN) (5.02 +/- 0.97 vs 4.19 +/- 0.79) and TP(LN) (6.36 +/- 1.02 vs 5.62 +/- 0.65) compared with the post-PHV group. When postexercise LF(LN) (ms(2)) was normalized for TP(LN) (ms(2)), there were no significant differences between groups (P > 0.05). CONCLUSION: The pre-PHV group had higher total HR variability than the post-PHV group after a Wingate test, suggesting that maturity status significantly affects total HR variability during recovery after high-intensity exercise.

Adolescent↗

PubMed2006

Cardiac autonomic control in individuals with Down syndrome.

Our goal in this study was to compare cardiac autonomic control at rest between 50 individuals with Down syndrome and 24 control participants without disabilities. Resting autonomic function was assessed using analysis of heart rate variability. Participants with Down syndrome had reduced total heart rate variability, which indicates possible autonomic dysfunction in this population. Their VO2 peak and BMI were not significantly correlated with resting cardiac autonomic control. This may suggest that fitness level and obesity differentially affect cardiac autonomic control in persons with Down syndrome compared to their healthy, nondisabled peers.

Adult↗

PubMed2005

Impaired vagal modulation of heart rate in individuals with Down syndrome.

The attenuated heart rate (HR) and blood pressure (BP) response to exercise in individuals with Down syndrome (DS) has been attributed to autonomic dysfunction, which has been associated with obesity. Our purpose was to determine the role of autonomic control of HR to the attenuated chronotropic response observed in individuals with DS. We evaluated spectral analysis of HR variability (HRV) in 13 individuals with (BMI 32+/-5 kg/m(2), P<0.05) and 14 without DS (BMI 26+/-3 kg/m(2)) by means of 2 min isometric handgrip at 30% of maximal force followed by recovery. Noninvasive measures of HR (ECG) and systolic BP (SBP) (Portapres) were recorded continuously. The increases in HR and SBP, and decrease in high frequency (HF) component were significantly greater in controls than in individuals with DS (P<0.05) during handgrip. The increase in LF/HF ratio was not significantly affected by handgrip and was comparable in both groups. During recovery, the decreases in HR, SBP, and LF/HF ratio, and the increase in HF were significantly greater in controls than in individuals with DS (P<0.05). Controlling for BMI did not alter these results. The attenuated HR and SBP response to the handgrip test in individuals with DS is explained by blunted vagal modulation. Our study suggests that autonomic dysfunction in individuals with DS might be independent of obesity.

Adolescent↗

PubMed2005

Blunted heart rate response to upright tilt in people with Down syndrome.

OBJECTIVES: To determine whether heart rate and blood pressure responses to upright tilt would be lower in subjects with Down syndrome (DS) than in control subjects with no disabilities. DESIGN: Comparative study. SETTING: University research laboratory. PARTICIPANTS: Nineteen people with DS (mean age, 25.1+/-7.3 y) and 17 control subjects without disabilities (mean age, 28.4+/-5.6 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Heart rate and blood pressure recordings were obtained at rest and during a 2-minute period of passive head up tilt to 80 degrees . RESULTS: Heart rate and blood pressure increased significantly during the first 30 seconds of upright tilt in both groups ( P <.05) and then stabilized for the remainder of the test. The initial heart rate response to head up tilt (first 30s) was significantly higher in controls compared with subjects with DS ( P <.05), whereas the blood pressure response did not differ between groups ( P >.05). Controlling for heart rate reserve showed a blunted heart rate response through the tilt period in subjects with DS. CONCLUSIONS: These data show a blunted heart rate response to upright tilt in people with DS, despite similar changes in blood pressure, consistent with reduced sympathoexcitation and possibly altered baroreceptor function in these people with DS.

Adolescent↗

PubMed2005

Effect of a single vs multiple bouts of exercise on glucose control in women with type 2 diabetes.

The Surgeon General and Centers for Disease Control and Prevention have recommended that multiple bouts of exercise can be accumulated throughout the day in lieu of the more traditional single, longer bout of exercise. Yet, conclusive evidence does not exist suggesting these 2 training modes provide similar health-related benefits on metabolic control, especially in individuals with type 2 diabetes. The purpose of this study was to determine if differences exist in glucose control when preceded by one 30-minute or three 10-minute bouts of exercise in women with type 2 diabetes. Nine individuals with type 2 diabetes (53 +/- 6 years old) and 6 control women (49 +/- 4 years old) completed 3 randomly ordered oral glucose tolerance tests (OGTTs). Two of the OGTTs were preceded the day prior by moderate exercise (approximately 60% of Vo2peak), either one 30-minute or three 10-minute bouts, whereas the third OGTT was used as a control day with no exercise performed 3 days prior. Glucose and insulin were measured every 30 minutes for 4 hours during the OGTT. Individuals with type 2 diabetes exhibited a greater overall glucose response than the controls (P < .05), but the glucose response to the OGTT was not different between the 3 conditions within each group (2-hour glucose: multiple bout, 14.3 +/- 3.2 vs 5.0 +/- 1.7; single bout, 14.1 +/- 3.0 vs 4.7 +/- 1.5; control day, 14.6 +/- 2.7 vs 4.9 +/- 4.9 mmol/L). Glucose area under the curve analysis resulted in similar findings. As expected, the group with type 2 diabetes had greater fasting insulin levels compared with the control group for all exercise conditions (multiple bout: 4.5 +/- 1.2 vs 0.3 +/- 0.2; single bout: 6.4 +/- 1.6 vs 0.9 +/- 0.4; control day: 5.7 +/- 1.8 vs 1.5 +/- 0.6 pmol/L; P < .05). Exercise or no exercise did not alter the insulin response to the OGTT for either group. Despite a higher glucose response to the glucose load in T2D, an acute exercise bout (single or multiple bouts) did not appear to alter glucose control the following day in either the individuals with type 2 diabetes or the control group.

Blood Glucose↗

PubMed2005

Baroreflex sensitivity during static exercise in individuals with Down Syndrome.

INTRODUCTION: Individuals with Down syndrome (DS) have altered heart rate (HR) and blood pressure (BP) responses to orthostatic challenges and isometric handgrip (IHG) exercise, suggesting possible alteration in baroreflex sensitivity. PURPOSE: This study investigated baroreflex sensitivity (BRS) as a potential mechanism contributing to chronotropic incompetence during IHG in persons with DS. METHODS: Heart rate and BP were continually recorded in 12 individuals with DS and 10 controls, at rest and during 2 min of IHG, at 30% of maximal voluntary contraction (MVC). Spontaneous BRS was derived via the sequence method. RESULTS: No differences were seen in HR at rest between groups. Systolic BP (SBP) was significantly lower in the DS group at rest (106.1+/- 2.9 vs 116.5+/- 3.9 mm Hg, P < 0.05) and during IHG (123.9+/- 4.6 vs 150.1+/- 5.3 mm Hg, P<0.001). A significant group-by-task interaction was found for both change in HR and change in SBP with IHG, because of an attenuated HR and SBP response to IHG in participants with DS (P<0.05). When controlling for resting SBP, the DS group had a lower BRS at rest (16.0+/-1.7 vs 21.2+/-4.2 ms.mm Hg, P< 0.05) and during IHG (7.8 +/-1.0 vs 12.1+/- 2.6 ms.mm Hg, P< 0.05). CONCLUSIONS: Individuals with DS have lower BRS at rest and during IHG than controls and this may be related to their attenuated HR response during perturbation.

Adult↗

PubMed2005

Resting metabolic rate is not reduced in obese adults with Down syndrome.

Resting metabolic rate (RMR) of 22 individuals with Down syndrome was compared to that of 20 nondisabled control individuals of similar age (25.7 and 27.4 years, respectively). Using a ventilated hood system, we measured RMR in the early morning after an overnight fast. Peak aerobic capacity (VO2peak) and body composition were also determined. Resting metabolic rate was not different between groups. Adjusting RMR for body weight or body surface area did not change these findings. Using stepwise regression for the total population and each subgroup, we found that only body surface area was a significant predictor of RMR. These data show that individuals with Down syndrome do not have lower RMR than their nondisabled peers, suggesting that reduced RMR does not explain the high incidence of obesity in this population.

Adolescent↗

PubMed2004

Nutrition for the pediatric athlete.

A paucity of literature exists with regard to research on nutrition for the pediatric athlete. This lack of research makes the development of specific nutritional recommendations for young athletes problematic. This issue is made difficult by the macro- and micronutrient intake required for growth and development in conjunction with that required for sports. Exogenous carbohydrate drinks could be considered for the young athlete engaged in both endurance exercise and high-intensity exercise. Monitoring of the energy intake during resistance training in the pediatric athlete needs to be considered, as there is evidence to suggest that energy deficits may occur. If decrements in exercise performance are noted, then serum ferritin and hemoglobin concentrations should be monitored, as nonanemic iron deficiency is prevalent in the pediatric athlete. The pediatric athlete exercising in the heat is susceptible to voluntary dehydration and evidence exists to suggest that a carbohydrate-electrolyte drink will abolish this phenomenon.

Adolescent↗