[Exercise as a tool to reduce body weight]

Modified Talk Test: a Randomized Cross-over Trial Investigating the Comparative Utility of Two "Talk Tests" for Determining Aerobic Training Zones in Overweight and Obese Patients

BACKGROUND

To validate the traditional talk test (TTT) and an alternative talk test (ATT; using a visual analog scale) in overweight/obese (OW-OB) patients and to establish its accuracy in determining the aerobic training zones.

METHODS

We recruited 19 subjects aged 34.9 ± 6.7 years, diagnosed with overweight/obesity (BMI 31.8 ± 5.7). Every subject underwent incremental cycloergometric tests for maximal oxygen consumption, and TTT in a randomized order. At the end of each stage during the TTT, each subject read out loud a 40 words text and then had to identify the comfort to talk in two modalities: TTT which consisted in answering "Yes," "I don't know," or "No" to the question Was talking comfortable?, or ATT through a 1 to 10 numeric perception scale (visual analog scale (VAS)). The magnitude of differences was interpreted in comparison to the smallest worthwhile change and was used to determine agreement.

RESULTS

There was an agreement between the power output at the VAS 2-3 of ATT and the power output at the ventilatory threshold 1 (VT1) (very likely equivalent; mean difference - 1.3 W, 90% confidence limit (CL) (- 8.2; 5.6), percent chances for higher/similar/lower values of 0.7/99.1/0.2%). Also, there was an agreement between the power output at the VAS 6-7 of ATT and the power output at the ventilatory threshold 2 (VT2) (very likely equivalent; mean difference 11.1 W, 90% CL (2.8; 19.2), percent chances for higher/similar/lower values of 0.0/97.6/2.4%).

CONCLUSIONS

ATT is a tool to determine exercise intensity and to establish aerobic training zones for exercise prescription in OW-OB patients.

Effects of High-Intensity Interval Training vs. Sprint Interval Training on Anthropometric Measures and Cardiorespiratory Fitness in Healthy Young Women

Purpose: To compare the effects of 8 weeks of two types of interval training, Sprint Interval Training (SIT) and High-Intensity Interval Training (HIIT), on anthropometric measures and cardiorespiratory fitness in healthy young women.

Methods: A randomized clinical trial in which 49 young active women [age, 30.4 ± 6.1 years; body mass index, 24.8 ± 3.1 kg.m⁻²; peak oxygen consumption (VO₂peak), 34.9±7.5 mL.kg⁻¹.min⁻¹] were randomly allocated into a SIT or HIIT group. The SIT group performed four bouts of 30 s all-out cycling efforts interspersed with 4 min of recovery (passive or light cycling with no load). The HIIT group performed four bouts of 4-min efforts at 90–95% of peak heart rate (HRpeak) interspersed with 3 min of active recovery at 50–60% of HRpeak. At baseline and after 8 weeks of intervention, waist circumference, skinfolds (triceps, subscapular, suprailiac, abdominal, and thigh), body mass and BMI were measured by standard procedures and cardiorespiratory fitness was assessed by cardiorespiratory graded exertion test on an electromagnetically braked cycle ergometer.

Results: The HIIT and SIT groups improved, respectively, 14.5 ± 22.9% (P < 0.001) and 16.9 ± 23.4% (P < 0.001) in VO₂peak after intervention, with no significant difference between groups. Sum of skinfolds reduced 15.8 ± 7.9 and 22.2 ± 6.4 from baseline (P < 0.001) for HIIT and SIT groups, respectively, with greater reduction for SIT compared to HIIT (P < 0.05). There were statistically significant decreases in waist circumference (P < 0.001) for the HIIT (−3.1 ± 1.1%) and SIT (−3.3 ± 1.8%) groups, with no significant difference between groups. Only SIT showed significant reductions in body weight and BMI (p < 0.05).

Conclusions: Eight weeks of HIIT and SIT resulted in improvements in anthropometric measures and cardiorespiratory fitness, even in the absence of changes in dietary intake. In addition, the SIT protocol induced greater reductions than the HIIT protocol in the sum of skinfolds. Both protocols appear to be time-efficient interventions, since the HIIT and SIT protocols took 33 and 23 min (16 and 2 min of effective training) per session, respectively.

[Moderate exercise and intake of either high or low glycemic index carbohydrates in sedentary women]

Objetivo

Analizar los cambios en las concentraciones de glucosa, insulina y triglicéridos sanguíneos en relación con un ejercicio aerobio moderado en mujeres sedentarias de distinto peso corporal, expuestas a una dieta rica en hidratos de carbono de alto o bajo índice glucémico.

Diseño

Tipo cruzado.

Emplazamiento

Se realizó en el Laboratorio de Fisiología del Ejercicio de la Facultad de Ciencias de la Cultura Física de la Universidad Autónoma de Chihuahua, México.

Participantes

Participaron 26 mujeres jóvenes sedentarias que no realizaron ejercicio en el último año. Se excluyeron 4 de peso adecuado (PA) y 2 con obesidad (OB) por no consumir los hidratos de carbono indicados (1 g/kg de peso) ni completar el ejercicio programado. Quedaron n = 10 en cada grupo (PA/OB).

Intervención

Se aplicaron 2 tratamientos de 55 min de ejercicio aerobio cada uno, un día después de consumir hidratos de carbono de alto o de bajo índice glucémico.

Mediciones principales

Se determinaron glucosa, insulina y triglicéridos plasmáticos, antes y después del ejercicio programado.

Resultados

Glucosa, insulina y triglicéridos fueron más altos en OB que en PA al inicio del estudio. La glucosa se normalizó en OB de 5,8 ± 0,35 a 5,3 ± 0,23 mmol/L (p = 0,001), solo por ingerir alimentos de bajo índice glucémico; los triglicéridos incrementaron de 139,5 ± 66 a 150,8 ± 67,2 mg/dl (p = 0,004), al término del ejercicio, habiendo consumido alimentos de bajo índice glucémico.

Conclusión

La elevación de triglicéridos secundaria al ejercicio posterior al consumo de bajo índice glucémico parece indicar aumento de oxidación lipídica en OB.