Daniel Gomes da Silva Machado

Slow Down and Enjoy: The Effects of Cycling Cadence on Pleasure.

Pleasure plays a key role in exercise behavior. However, the influence of cycling cadence needs to be elucidated. Here, we verified the effects of cycling cadence on affect, perceived exertion (ratings of perceived exertion), and physiological responses. In three sessions, 15 men performed a maximal cycling incremental test followed by two 30-min constant workload (50% of peak power) bouts at 60 and 100 r/min. The pleasure was higher when participants cycled at 60 r/min, whereas ratings of perceived exertion, heart rate, and oxygen uptake were lower (p < .05). Additionally, the rate of decrease in pleasure and increase in ratings of perceived exertion was less steep at 60 r/min (p < .01). Cycling at 60 r/min is more pleasant, and the perceived effort and physiological demand are lower than at 100 r/min.

Drug abusers have impaired cerebral oxygenation and cognition during exercise

Background Individuals with Substance Use Disorder (SUD) have lower baseline metabolic activity of the prefrontal cortex (PFC) associated with impairment of cognitive functions in decision-making and inhibitory control. Aerobic exercise has shown to improve PFC function and cognitive performance, however, its effects on SUD individuals remain unclear. Purpose To verify the cognitive performance and oxygenation of the PFC during an incremental exercise in SUD individuals. Methods Fourteen individuals under SUD treatment performed a maximum graded exercise test on a cycle ergometer with continuous measurements of oxygen consumption, PFC oxygenation, and inhibitory control (Stroop test) every two minutes of exercise at different intensities. Fifteen non-SUD individuals performed the same protocol and were used as control group. Results Exercise increased oxyhemoglobin (O2Hb) and total hemoglobin (tHb) by 9% and 7%, respectively. However, when compared to a non-SUD group, this increase was lower at high intensities (p<0.001), and the inhibitory cognitive control was lower at rest and during exercise (p<0.007). In addition, PFC hemodynamics during exercise was inversely correlated with inhibitory cognitive performance (reaction time) (r = -0.62, p = 0.001), and a lower craving perception for the specific abused substance (p = 0.0189) was reported immediately after exercise. Conclusion Despite SUD individuals having their PFC cerebral oxygenation increased during exercise, they presented lower cognition and oxygenation when compared to controls, especially at elevated intensities. These results may reinforce the role of exercise as an adjuvant treatment to improve PFC function and cognitive control in individuals with SUD.

Self-selected intensity, ratings of perceived exertion, and affective responses in sedentary male subjects during resistance training.

[Purpose] This study examined the exercise intensity and psychophysiological responses to a self-selected resistance training session in sedentary male subjects. [Subjects and Methods] Twelve sedentary male subjects (35.8 ± 5.8 years; 25.5 ± 2.6 kg·m2) underwent four sessions at 48-h intervals: familiarization; two sessions of one repetition maximum test and a resistance training session in which they were told to self-select a load to complete 3 sets of 10 repetitions of chest press, leg press, seated rows, knee extension, overhead press, biceps curl, and triceps pushdown exercises. During the latter, the percentage of one repetition maximum, affective responses (feeling scale), and rating of perceived exertion (OMNI-RES scale) were measured. [Results] The percentage of one repetition maximum for all exercises was >51% (14–31% variability), the rating of perceived exertion was 5–6 (7–11% variability), and the affective responses was 0–1 point with large variability. [Conclusion] Sedentary male subjects self-selected approximately 55% of one maximum repetition, which was above the intensity suggested to increase strength in sedentary individuals, but below the recommended intensity to improve strength in novice to intermediate exercisers. The rating of perceived exertion was indicative of moderate intensity and slightly positive affective responses.

Poorer positive affect in response to self-paced exercise among the obese

We aimed to investigate the association between body mass index (BMI) and affective response, ratings of perceived exertion (RPE), and physiological responses during self-paced exercise. Sixty-six women were divided into three groups accordingly with the BMI: obese (n = 22: 33.5 ± 8.5 yr; 34.9 ± 4.1 kg∙m-2), overweight (n = 22: 34.8 ± 8.6 yr; 26.4 ± 1.3 kg∙m-2), and normal-weight (n = 22: 30.8 ± 9.3 yr; 22.0 ± 1.6 kg∙m-2). They underwent a graded exercise test and a 20-min self-paced walking session on a treadmill. Affective responses, RPE, heart rate (HR), and oxygen uptake (VO2) were recorded every 5 min. The women with obesity experienced the lowest affective rates (p < .001), despite similar RPE, HR, and VO2 to the other normal weight and overweight groups. In addition, a multiple regression model indicated that BMI was a significant predictor of affective responses (p < .001). In conclusion, the results of the present study suggest that obesity is associated with poorer affective responses to exercise even at self-paced intensity, with the same physiological responses and perceived exertion. Therefore, techniques that aim directly to increase pleasure and/or reduce attentional focus and perception of effort in this population are required, such as affect-regulated prescription, shorter bouts of self-paced exercise throughout the day, distraction away from internal cues (e.g. music, group exercise), etc.

Mental fatigue impairs technical performance and alters neuroendocrine and autonomic responses in elite young basketball players

This study investigated the effects of mental exertion on Small-Sided-Games (SSG) technical performance, salivary testosterone (T), cortisol (C), and alpha-amylase (sAA) responses in 32 basketball players (15.2 ± 1.2 years; 180 ± 11 cm; 72 ± 15 kg). Technical performance and heart rate (HR) were assessed on two occasions, preceded by a 30-min incongruent Stroop task (mentally exertion treatment) or a 30-min control treatment. Saliva samples were collected before and after the treatment and after the SSG, and ratings of perceived exertion (session-RPE) was assessed. Large increase was observed from pre-control treatment to post-SSG for T (ES = 0.98) and sAA (ES = 0.82), but there was a small difference from pre-Stroop-task to post-SSG in T (ES = 0.33) and a moderate difference for sAA (ES = 0.55). Small changes in C for both conditions were observed (ES = 0.00 and 0.15, respectively). There were small differences between treatments for session-RPE (ES = 0.07), maximum (ES = -0.35) and average HR (ES = -0.16). Increased turnovers during the SSG (ES = 0.71) was seen following the Stroop task. The data suggest that mental fatigue state is a key regulator of technical performance of basketball players and that mental fatigue seems to modulate endocrine and autonomic responses.

Effect of resistance training with different frequencies and subsequent detraining on muscle mass and appendicular lean soft tissue, IGF-1, and testosterone in older women

Abstract Objective: To analyse the effect of resistance training (RT) frequency on muscle mass, appendicular lean soft tissue, insulin-like growth factor 1 (IGF-1), testosterone, and their changes with detraining in older women. Methods: Forty-five physically independent older women (≥ 60 years) were randomly assigned to perform RT either two (G2X, n = 21) or three times/week (G3X, n = 24), during 12 weeks (8 exercises, 1 set of 10–15 repetition maximum). Muscle mass and appendicular lean soft tissue, IGF-1, testosterone, and dietary intake were measured at pre-training, post-training, and after detraining (12 weeks). Results: Muscle mass and appendicular lean soft tissue significantly increased post-training (G2X = +5.5% and G3X = +5.8%, P < .0001) with no differences between groups, and gains were retained after detraining (G2X = 100% and G3X = 99%, P < .0001). IGF-1 and dietary intake did not change for the groups during the study. Testosterone did not change post-training but significantly decreased after detraining (G2X = −21% and G3X = −50%, P < .0001). Conclusion: We conclude that lower RT frequency is as effective as higher frequency to improve muscle mass and appendicular lean soft tissue, and to maintain testosterone and IGF-1. Additionally, detraining may reduce testosterone regardless of RT frequency. These results are specifically for community-dwelling older women and may not be generalized to other populations.

EFEITO DO ESFORÇO FÍSICO NO DESEMPENHO DE TIRO DE POLICIAIS MILITARES DO BATALHÃO DE CHOQUE

ABSTRACT Introduction: The use of firearms by military police officers is usually preceded by pursuit on foot, and the physiolog -ical changes produced by physical exertion may affect shooting performance. Objective: To verify the effect of physical effort on shooting performance in military police officers. Methods: The sample consisted of 15 men (34.1 ± 5.4 years; 81.4 ± 8.8 kg; 171.3 ± 5.6 cm; 27.7 ± 2.3 kg/m²; 44.9 ± 4.0 ml.kg -1 .min -1 ) of the riot police. In the first session, the subjects performed a maximal treadmill stress test in which the peak oxygen consumption (VO 2peak ) was measured. In the second session, shooting performance (score) and shooting time were measured pre and post-exercise, as well as the time spent to complete a circuit of obstacle running (297 m). Shooting efficiency index was calculated as the ratio between total score and shooting time. The Shapiro-Wilk test confirmed the normal distribution of the data. A paired t-test was used to compare the post-exertion outcomes variables as well as the Pearson correlation coefficient. Results: The time to complete the running circuit was 75.3 ± 4.4 s. Shooting performance (20.4 ± 11.4 vs. 17.6 ± 9.3 points), time (4.48 ± 1.1 vs. 4.23 ± 0.9 s), and efficiency (4.69 ± 2.7 vs. 4.35 ± 2.7 pts/s) did not present significant differences (P>0.2). Additionally, a correlation was detected between VO

Affect during incremental exercise: The role of inhibitory cognition, autonomic cardiac function, and cerebral oxygenation

Background Pleasure is a key factor for physical activity behavior in sedentary individuals. Inhibitory cognitive control may play an important role in pleasure perception while exercising, especially at high intensities. In addition, separate work suggests that autonomic regulation and cerebral hemodynamics influence the affective and cognitive responses during exercise. Purpose We investigated the effects of exercise intensity on affect, inhibitory control, cardiac autonomic function, and prefrontal cortex (PFC) oxygenation. Methods Thirty-seven sedentary young adults performed two experimental conditions (exercise and control) in separate sessions in a repeated-measures design. In the exercise condition, participants performed a maximum graded exercise test on a cycle ergometer as we continuously measured oxygen consumption, heart rate variability (HRV), and PFC oxygenation. At each of 8 intensity levels we also measured inhibitory control (Stroop test), associative and dissociative thoughts (ADT), and affective/pleasure ratings. In the control condition, participants sat motionless on a cycle ergometer without active pedaling, and we collected the same measures at the same points in time as the exercise condition. We evaluated the main effects and interactions of exercise condition and intensity level for each measure using two-way repeated measures ANOVAs. Additionally, we evaluated the relationship between affect and inhibitory control, ADT, HRV, and PFC oxygenation using Pearson’s correlation coefficients. Results For exercise intensities below and at the ventilatory threshold (VT), participants reported feeling neutral, with preservation of inhibitory control, while intensities above the VT were associated with displeasure (p<0.001), decreased inhibitory control and HRV (p<0.001), and increased PFC oxygenation (p<0.001). At the highest exercise intensity, pleasure was correlated with the low-frequency index of HRV (r = -0.34; p<0.05) and the low-frequency/high-frequency HRV ratio (r = -0.33; p<0.05). PFC deoxyhemoglobin was correlated with pleasure two stages above the VT (r = -0.37; p<0.05). Conclusion Our results support the notion that exercise at high intensities influences inhibitory control and one’s perception of pleasure, which are linked to changes in cardiac autonomic control and cerebral hemodynamics. These findings strengthen the existence of an integrated brain-heart-body system and highlight the importance of exercise intensity in exercise-related behavior in sedentary individuals.