Paulo Sehl

Intensive practical lifestyle intervention improves endothelial function in metabolic syndrome independent of weight loss: a randomized controlled trial

The objective was to evaluate the metabolic and vascular effects of lifestyle interventions involving a healthy diet and either a moderate- or a high-intensity exercise regimen in nondiabetic subjects with metabolic syndrome. The effects of these interventions on flow-mediated vasodilation (FMD) and risk profiles were compared with a standard low-fat diet and engaging in daily walking (standard of care). Seventy-five healthy adults with metabolic syndrome (30-55 years old) were randomized to a 10,000-steps-a-day exercise program, a 3-times-a-week fitness (>75% peak VO(2)) program, or a 1-hour-walking-a-day program for 12 weeks. The first 2 interventions were combined with an accessible healthy, no-sugar diet; and the third was combined with a tailored low-fat diet. The outcomes, including FMD and risk factors, were examined at 12 weeks and at 1-year reassessment. Significant increase in FMD (mean difference = 1.51%, 95% confidence interval = 1.05%-3.017%, P = .0007) and decrease in arterial pressure (mean difference = 19.3 ± 2.3/-12.6 ± 1.8 mm Hg, P = .0001) were observed in all groups. However, the FMD changed most favorably in the high-intensity, low-sugar group (mean difference = 1.56%, 95% confidence interval = 0.1%-3.02%, P = .036). Significant improvements in body mass index, waist, insulin-like growth factor-1, homeostasis model assessment of insulin resistance, insulin, glucose, urinary albumin excretion, and lipid profiles occurred in all groups. Metabolic syndrome was resolved in 64%. One year later, weight loss (-9.1 ± 2.3 kg, P = .0001) and arterial pressure decrease (-18.5 ± 2.3/-12.3 ± 2.1 mm Hg, P = .0001) were maintained. Practical, health-centered diet combined with high-intensity exercise is associated with enhanced vascular protection. These data suggest that more intense exercise combined with a low-sugar diet modulates endothelium-dependent vasodilation.

Responses of Obese and Lean Girls Exercising under Heat and Thermoneutral Conditions

OBJECTIVE To compare thermoregulatory and perceptual responses between lean and obese girls during and after exercise under heat (HC) and thermoneutral (TC) conditions. STUDY DESIGN In a randomized order, 27 girls (14 lean [16.6 ± 6.7% fat and 9.1 ± 1.3 years] and 13 obese [41.3 ± 6.7% fat and 9.4 ± 1.1 years]) cycled 30 minutes at ~55% peak oxygen uptake in 2 sessions, which only differed in the thermal conditions (35 °C and 40% relative humidity vs 24 °C and 50% relative humidity). RESULTS Initial rectal temperature (T(re)) was higher in obese versus lean during HC (37.5 ± 0.3 °C vs 37.3 ± 0.3 °C, P = .03) and TC (37.6 ± 0.3 °C vs 37.3 ± 0.2 °C; P = .03) sessions. During cycling, Tre remained higher in the obese, but the rate of increase was greater in the lean. This change occurred mainly in the HC, when final Tre of the lean surpassed that of the obese (37.8 ± 0.2 vs 38.0 ± 0.2 °C, P = .04). Sweat volume (in mL · m(-2)) was similar between lean and obese in the HC (167 ± 119 and 120 ± 145) and TC (200 ± 196 vs 72 ± 20). Heart rate, rate of perceived exertion, and thermal sensation were similar between groups, independent of the thermal condition. Cycling in HC produced decreased thermal comfort (P = .009) and increased irritation (P = .02) within the lean girls. CONCLUSION Thermoregulatory and perceptual responses of prepubescent obese girls during 30 minutes of cycling at a similar relative intensity do not seem to be impaired when comparing with a lean group either in TC or HC.

Responses of obese and non-obese boys cycling in the heat.

This study compared rectal temperature (Tre), heat sensation and sweating between obese and non-obese boys during cycling in the heat. Participants (aged 12-15 years) were 17 obese and 16 non-obese (BMI=29.4±4.3 and 16.8±1.7 kg · m⁻², respectively) boys. They cycled for 30-min (50-55% VO(2peak)) in a climatic chamber (35°C, 45% RH) and Tre, heat sensation and sweat volume were monitored. From the start to the end of cycling, Tre was similar between the obese (37.4±0.3-37.8±0.3°C) and non-obese (37.3±0.2-37.9±0.2°C) groups. Heat sensation was higher in the obese group from the start (3.6±2.7 vs. 1.3±1.4 cm; P=0.008) to the end (7.6±2 vs. 5.2±2.2 cm; P=0.003) of cycling. Sweat volume corrected by body surface area was similar between the obese (200±123 mL · m⁻²) and non-obese (212±80 mL · m⁻²) groups. Initial and final HR were similar in both groups, and RPE was higher in the obese group at 25th (P=0.040) and 30th (P=0.019) min. In conclusion, the obese pubescent participants presented similar Tre and sweating volume, but higher heat sensation while cycling in the heat.

Hydration and Perceptual Responses Resulting from a Training Session Involving Female Rhythmic Gymnastics Athletes

Young rhythmic gymnastics (RG) athletes engage in long training sessions that can lead to dehydration, especially on very hot days. Hydration status can affect the sporting performance and health maintenance of these young gymnasts. To evaluate the sweat volume, fluid balance and perceptual responses of young female RG athletes during a training session in the heat, fourteen female RG athletes (11.3±2.6 years) with a body fat percentage of 17.35±4.85% participated in this study. Body weight was measured and a urine sample collected for color analysis, both before and after the training session. The workout lasted 2.5 h in environmental conditions of between 29 °C and 50% relative humidity (RH), and 30 °C and 59% RH. Water was made available for consumption ad libitum and sweat volume was calculated from the change in body weight, corrected for water intake. The rate of perceived exertion, thermal sensation, thermal comfort, and irritability were measured every 30 minutes using categorical scales. Sweat volume was 1146.6±412.6 mL and water consumption was 825.2±368.1 mL. The negative fluid balance was between 1-2% in 50% and 1% in 42.8% of the athletes. Twelve athletes began the training session hypohydrated (urine color between 3 and 7), and 92.3% were hypohydrated after training (urine color between 4 and 6). There was an increase in thermal sensation (8±1) and discomfort (3±1) over the course of the workout. The RG athletes were unable to adequately replace their fluid losses, despite water being available for drinking ad libitum, which may reflect on the perceptual responses to heat.