Gender-based differences in substrate use during exercise at a self-selected pace

The aim of this study was to investigate gender-based differences in substrate use during exercise at a self-selected pace. Seventeen men and 17 women performed a maximal exercise test and a 20-minute bout of self-paced treadmill walking to determine carbohydrate and fat oxidation rates. Gas exchange measurements were performed throughout the tests, and stoichiometric equations were used to calculate substrate oxidation rates. For each individual, a best-fit polynomial curve was constructed using fat oxidation rate (gmin21) vs. exercise intensity (percentage of maximal oxygen uptake, % _ VO2max). Each individual curve was used to obtain the following variables: maximal fat oxidation (MFO), the peak rate of fat oxidation measured over the entire range of exercise intensities; fatmax, the exercise intensity at which the MFO was observed; and fatmax zone, range of exercise intensities with fat oxidation rates within 10% of fat oxidation rates at fatmax. Although the MFO was similar between genders, fatmax was lower in men than in women. Similarly, the ‘‘low’’ and ‘‘high’’ borders of the fatmax zone were lower in men than in women. During exercise at a self-selected pace, carbohydrate oxidation rates were greater in men than in women, despite no gender-based differences in fat oxidation rates. However, fat oxidation contribution to total energy expenditure (EE) was greater in women than in men, despite no gender-based differences in the exercise intensity. In conclusion, although both genders self-selected a similar exercise intensity, the contribution of fat oxidation to EE is greater in women than in men. Interestingly, both genders selfselected an exercise intensity that falls within the fatmax zone

Psychophysiological Responses to Self-paced Treadmill and Overground Exercise

Speculation exists that a positive affective response experienced during exercise may play an important role in predicting exercise adherence. Previous studies using self-paced exercise protocols have been associated with health benefits and pleasant experiences. However, all of these studies were conducted in laboratories, and consequently, the external validity of the findings may be questionable. PURPOSE: To determine whether environmental settings (treadmill vs overground) differentially influence physiological, perceptual, and affective responses to exercise at a self-selected pace. METHODS: Thirty-four individuals (17 men and 17 women) between 18 and 30 yr volunteered to participate in this study. During the orientation session, individuals underwent an initial screening, anthropometric measurements, and familiarization with the experimental procedures. Next, subjects underwent a maximal treadmill test. In the two experimental trials, participants performed 20-min bouts of treadmill and overground walking at a self-selected pace, which were completed in a counterbalanced order. At least 48 h separated experimental trials. RESULTS: Using repeated-measures ANOVA, overground walking speed was significantly faster than treadmill walking speed (P < 0.01) during the 20-min bout of self-paced exercise. However, exercise intensity (%VO2R and %HRR) and perceived exertion during the session of overground walking were significantly lower (P < 0.05) when compared with those during the treadmill session. In addition, affective valence was more positive during the session of overground walking than during the treadmill session (P < 0.01). CONCLUSIONS: These data extend previous findings by showing that environmental setting influences physiological, perceptual, and affective responses during exercise at a self-selected pace. Self-paced exercise performed over ground resulted in lower perceptual and more positive affective responses

Physiological and perceived responses obtained during gait in self-selected rhythm by women with different body mass indices [Respostas fisiológicas e perceptuais obtidas durante a caminhada em ritmo autosselecionado por mulheres com diferentes índices de massa corporal]

Physiological and perceived responses verified during gait have been widely studied; however, few investigations have tried to compare these responses in groups of different body mass indices during gait in self-selected rhythm. The aim of the present study was to compare the physiological and perceived responses among normative (N), overweighed (OW) and obese ( OB) women during gait in self-selected rhythm. Sixty-six sedentary women, aged between 20 and 45 years and divided in three groups according to their body mass indices participated in the study: (i) N (18.5-24.9kg.m(-2), n = 22); (ii) OW (25.0 - 29.9kg.m(-2), n = 22) and (iii) OB (>= 30.0kg.m(-2), n = 22). Each participant performed a familiarization session and two experimental sessions (maximal incremental test and 20m-walking test in self-selected rhythm) to determine the physiological ( heart rate - HR and oxygen consumption - O(2)) and perceived responses ( perceived exertion - PE) of each session. One-way ANOVA was applied to compare the physiological and perceived responses obtained during gait in self-selected rhythm among the three experimental protocols, applying the Tukey's post hoc test with p < 0.05. Although the obese subjects have registered lower walking velocity (1.30 +/- 0.13m.s(-1)) compared with the normative and overweighed ones (1.69 +/- 0.11 and 1.58 +/- 0.22m.s(-1), respectively) ( p < 0.05), they presented similar physiological response ((58.7 +/- 8.6; 63.1 +/- 12.6; 64.8 +/- 11.1 %O(2) and 75.1 +/- 7.8; 78.8 +/- 8.5; 78.7 +/- 7.2 % HR(max), for the normative, overweighed and obese groups, respectively). Moreover, the perceived responses did not differ between experimental groups (11.6 +/- 1.6; 11.7 +/- 1.6; 12.2 +/- 1.8, respectively). Therefore, it can be concluded that regardless of the BMI, adult women present similar physiological and perceived responses during gait in self-selected rhythm even when walking in different velocities

Physiological responses during treadmill walking at a self-selected pace: comparison between genders [Respostas fisiológicas durante a caminhada na esteira em ritmo autosselecionado:comparação entre os gêneros]

The objective of this study was to compare % VO2Max, %HRMax, %HRR, % VO2R, and MET between genders during walking at a self-selected pace and to determine whether the self-selected pace was physiologically effective in maintaining and improving cardiorespiratory fitness. Seventeen men (age: 24.05 ± 3.3 years) and 17 women (age> 22.58 ± 2.67 years) were submitted to two experimental sessions: (I) anthropometric assessment and incremental exhaustion test, and (II) 20-min treadmill walking bouts at a self-selected pace. The independent Student t-test was used to determine differences between genders, at an alpha level of 0.05. No significant differences in %HRMax (58.38 ± 8.86 for men and 62.12 ± 5.91 for women), % O2Max (37.54 ± 10.75 for men and 40.34 ± 7.27 for women), %HRR (36.83 ± 11.77 for men and 38.46 ± 8.33 for women), or % VO2R (31.88 ± 11.17 for men and 34.70 ± 7.74 for women) were observed between genders. However, the walking speed selected (km.h-1) was higher in men (5.96 ± 0.66, p<0.001) than women, a finding that probably resulted in higher MET values for men (6.07 ± 1.57, p<0.05) compared to women (5.23 ± 0.77). In conclusion, both genders selected a walking pace that was not effective in maintaining or improving cardiorespiratory fitness, but MET values were within the range indicated for the maintenance and reduction of body weight. The differences in METs observed between genders might be due to differences in walking speed and anthropometric characteristics

Age and physiological, perceptual, and affective responses during walking at a self-selected pace

The aim of this study was to examine physiological, perceptual, and affective responses during self-paced walking for three age groups. 66 adult women were assigned into three groups by age: 20–25 yr. (n = 22), 30–35 yr. (n = 22), and 40–45 yr. (n = 22). Each participant completed a maximal exercise test and a 20-min. bout of walking at a self-selected pace. The preferred walking speed was similar for all age groups, whereas physiological responses relative to maximal and ventilatory threshold values were greater in the 40–45 yr. group than the other two groups. Nevertheless, perceptual and affective responses were similar for all age groups. These findings suggest that physiological responses, but not perceptual and affective responses, of sedentary women are associated with age during walking at a self-selected pace

Physiological and perception responses comparison during treadmill walking at self-selected pace between genders | [Comparação das respostas fisiológicas e perceptuais obtidas durante caminhada na esteira em ritmo autosselecionado entre os sexos]

The aim of this study was to compare physiological and perception responses between genders during treadmill walking at self-selected pace. 17 men and 17 women aged 23.32 ± 3.06 yr were investigated: (I) anthropometric assessment and incremental exhaustion test, (II) a 20-minute walking bout on treadmill at their self-selected pace. The independent t test was utilized to verify any gender differences, with a level of p < 0.05. The self-selected walking pace was significantly greater in men than women (1.65 ± 0.18 and 1.50 ± 0.12 m.sec-1, respectively), and consequently resulted in higher absolute VO2 for men compared to women (21.2 ± 5.5 and 18.3 ± 2.7, respectively). However, both genders self-selected a similar relative exercise intensity %VO2max (37.5 ± 10.7 and 40.3 ± 7.2 for men and women, respectively). The subjective perceived exertion (SPE) did not differ between genders (10.2 ± 1.0 and 9.8 ± 1.2 for men and women, respectively). The results of the present study demonstrated that regardless of gender, physically active young adults self-selected a similar relative exercise intensity that reflected in similar SPE. Furthermore, gait at self-selected intensity was insufficient to improve cardio-respiratory fitness in this sample

The influence of adiposity on physiological, perceptual, and affective responses during walking at a self-selected pace

The aim of this study was to investigate the influence of adiposity (%body fat) on physiological, perceptual, and affective responses during walking. 45 women were divided into low, medium, and high tertiles according to %body fat. Each participant completed a maximal exercise test and a 20-min. bout of walking at a self-selected pace. The preferred walking speed was similar among groups, whereas %VO(2) max was greater in the high tertile group compared with the other two groups. Nevertheless, perceptual and affective responses were similar between the groups. These findings suggest that physiological responses relative to maximal capacity but not perceptual and affective responses, of sedentary women are influenced by adiposity during walking at a self-selected pace. However, when the physiological responses are relative to ventilatory threshold, there are no differences between individuals with different levels of adiposity