Relating cardiorespiratory responses to work rate during incremental ramp exercise on treadmill in children and adolescents: sex and age differences

PURPOSE: Evaluation of cardiopulmonary exercise testing (CPET) slopes such as [Formula: see text] (cardiac/skeletal muscle function) and [Formula: see text] (O2 delivery/utilization), using treadmill protocols is limited because the difficulties in measuring the total work rate ([Formula: see text]). To overcome this limitation, we proposed a new method in quantifying [Formula: see text] to determine CPET slopes.METHODS: CPET's were performed by healthy patients, (n=674, 9-18year) 300 female (F) and 374 male (M), using an incremental ramp protocol on a treadmill. For this protocol, a quantitative relationship based on biomechanical principles of human locomotion, was used to quantify the [Formula: see text] of the subject. CPET slopes were determined by linear regression of the data recorded until the gas exchange threshold occurred.RESULTS: The method to estimate [Formula: see text] was substantiated by verifying that: [Formula: see text] for treadmill exercise corresponded to an efficiency of muscular work similar to that of cycle ergometer; [Formula: see text] (mL min-1W-1) was invariant with age and greater in M than F older than 12 years old (13-14years: 9.6±1.5(F) vs. 10.5±1.8(M); 15-16years: 9.7±1.7(F) vs. 10.6±2.2(M); 17-18years: 9.6±1.7(F) vs. 11.0±2.3(M), p<0.05); similar to cycle ergometer exercise, [Formula: see text] was inversely related to body weight (BW) (r=0.71) or [Formula: see text] (r=0.66) and [Formula: see text] was not related to BW (r=- 0.01), but had a weak relationship with [Formula: see text] (r=0.28).CONCLUSION: The proposed approach can be used to estimate [Formula: see text] and quantify CPET slopes derived from incremental ramp protocols at submaximal exercise intensities using the treadmill, like the cycle ergometer, to infer cardiovascular and metabolic function in both healthy and diseased states

{A figure is presented}Consumption of Whole-Grain Cereals during Weight Loss: Effects on Dietary Quality, Dietary Fiber, Magnesium, Vitamin B-6, and Obesity

Objective: While various weight-management approaches produce weight loss, they may differ in dietary quality. We monitored changes in nutrient intakes in overweight and obese subjects on three different weight-management programs. Design: Randomized clinical trial (pilot study) with two 12-week phases: phase 1, weekly counseling; phase 2, monitoring only. Subjects/setting: One hundred eighty nonsmoking, sedentary overweight and obese adults began this outpatient study; 134 (body mass index [calculated as kg/m2]=30.9±2.4; age=42.3±1.2 years) were used in analyses. Intervention: Twenty-four weeks of exercise only (control group), hypocaloric diet plus exercise, or hypocaloric diet with fiber-rich whole-grain cereals plus exercise. Main Outcome Measures: At weeks 0, 12, and 24, diet quality was assessed by 3-day food records and body weight was measured. Statistical Analyses Performed: Three-way analysis of variance with repeated measures. Results: The hypocaloric diet with fiber-rich whole-grain cereals plus exercise decreased energy intake more than exercise only (P=0.032). By week 12, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise decreased total fat more than exercise only, which was sustained in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise at 24 weeks (P\u3c0.001). At weeks 12 and 24, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise reduced saturated fat intake more than exercise only. The hypocaloric diet with fiber-rich whole-grain cereals plus exercise increased total fiber, insoluble fiber (both P\u3c0.001), magnesium (P=0.004), and vitamin B-6 (P=0.002) intakes more than the hypocaloric diet plus exercise and exercise only. Calcium and vitamin E intakes were inadequate in all groups. Weight loss was similar in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise. Conclusions: Weight-reduction strategies may be associated with reduced intake of micronutrients, such as calcium and vitamin E. However, a hypocaloric diet with fiber-rich whole-grain cereal is effective for improving or maintaining other aspects of dietary quality during weight loss. © 2006 American Dietetic Association