Concomitant dual-site tDCS and dark chocolate improve cognitive and endurance performance following cognitive effort under hypoxia: a randomized controlled trial

Ten male cyclists were randomized into four experimental conditions in this randomized, cross-over, double-blind, and sham-controlled study to test the combined effect of acute dark chocolate (DC) ingestion and anodal concurrent dual-site transcranial direct current stimulation (a-tDCS) targeting M1 and left DLPFC on cognitive and whole-body endurance performance in hypoxia after performing a cognitive task. Two hours before the sessions, chocolate was consumed. After arriving at the lab, participants completed an incongruent Stroop task for 30 min in hypoxia (O2 = 13%) to induce mental fatigue, followed by 20 min of tDCS (2 mA) in hypoxia. Then, in hypoxia, they performed a time-to-exhaustion task (TTE) while measuring physiological and psychophysiological responses. Cognitive performance was measured at baseline, after the Stroop task, and during and after TTE. TTE in 'DC + a-tDCS' was significantly longer than in 'white chocolate (WC) + a-tDCS' and WC + sham-tDCS'. The vastus medialis muscle electromyography amplitude was significantly higher in 'DC + a-tDCS' and 'DC + sham-tDCS' than in 'WC + sh-tDCS'. During and after the TTE, choice reaction time was significantly lower in 'DC + a-tDCS' compared to 'WC + sh-tDCS'. Other physiological or psychophysiological variables showed no significant differences. The concurrent use of acute DC consumption and dual-site a-tDCS might improve cognitive and endurance performance in hypoxia.

Anodal tDCS over the left DLPFC but not M1 increases muscle activity and improves psychophysiological responses, cognitive function, and endurance performance in normobaric hypoxia: a randomized controlled trial

BACKGROUND

Transcranial direct current stimulation (tDCS) has been shown to have positive effects on exercise performance and cognitive function in the normal ambient condition. Hypoxia is deemed a stressful situation with detrimental effects on physiological, psychological, cognitive, and perceptual responses of the body. Nevertheless, no study has evaluated the efficacy of tDCS for counteracting the negative effects of hypoxic conditions on exercise performance and cognition so far. Hence, in the present study, we investigated the effects of anodal tDCS on endurance performance, cognitive function, and perceptual responses in hypoxia.

PARTICIPANTS AND METHODS

Fourteen endurance-trained males participated in five experimental sessions. After familiarization and measuring peak power output in hypoxia, in the first and second sessions, through the 3rd to 5th sessions, participants performed a cycling endurance task until exhaustion after 30 min hypoxic exposure at resting position followed by 20 min of anodal stimulation of the motor cortex (M1), left dorsolateral prefrontal cortex (DLPFC), or sham-tDCS. Color-word Stroop test and choice reaction time were measured at baseline and after exhaustion. Time to exhaustion, heart rate, saturated O₂, EMG amplitude of the vastus lateralis, vastus medialis, and rectus femoris muscles, RPE, affective response, and felt arousal were also measured during the task under hypoxia.

RESULTS

The results showed a longer time to exhaustion (+ 30.96%, p₌0.036), lower RPE (- 10.23%, p ₌ 0.045) and higher EMG amplitude of the vastus medialis muscle (+ 37.24%, p₌0.003), affective response (+ 260%, p₌0.035) and felt arousal (+ 28.9%, p₌0.029) in the DLPFC tDCS compared to sham. The choice reaction time was shorter in DLPFC tDCS compared to sham (- 17.55%, p₌0.029), and no differences were seen in the color-word Stroop test among the conditions under hypoxia. M1 tDCS resulted in no significant effect for any outcome measure.

CONCLUSIONS

We concluded that, as a novel finding, anodal stimulation of the left DLPFC might provide an ergogenic aid for endurance performance and cognitive function under the hypoxic condition probably via increasing neural drive to the working muscles, lowering RPE, and increasing perceptual responses.

Cognitive-Perceptual-Affective-Motivational Dynamics During Incremental Workload Accounting for Exertion Tolerance

Inquiry of the psychological states during the exercise experience failed to fully account for the role of motivation to adhere and the disposition of exertion tolerance (ET). The current study expands the scope of the integrated cognitive-perceptual-affective framework by measuring the motivation to sustain effort in two physical tasks and accounting for ET. Thirty male participants performed cycling and isometric handgrip tasks to assess the progression of the rating of perceived exertion, attentional focus, affective responses, and motivation to adhere, along with an incremental workload. The ET was determined by a handgrip task time to voluntary exhaustion. The findings indicated significant time effects and linear trends for perceived exertion, attentional focus, affect, and perceived arousal but not motivation to adhere during the handgrip and cycling tasks. The ET played a key role in the integrity of the model, particularly in perceptual, attentional, and affective responses. The intended model serves to stimulate new research into adaptation mechanisms.

The Effect of Resistance Exercise Movement Tempo on Psychophysiological Responses in Novice Men

Tavares, VDdO, Agrícola, PMD, Nascimento, PHD, Oliveira Neto, L, Elsangedy, HM, and Machado, DGS. The effect of resistance exercise movement tempo on psychophysiological responses in novice men. J Strength Cond Res 34(5): 1264-1273, 2020-This study aimed to compare the effects of movement tempo in resistance exercise (RE) on psychophysiological responses in novice men. Seventeen novice men (24.5 ± 3.2 years; 79.3 ± 8.22 kg; 1.76 ± 0.06 m) performed the 10 repetition maximum (10RM) test for bench press and knee extension in 2 sessions (test-retest) and 2 RE training sessions with different movement tempos in a random and counterbalanced order (4 sets of 10 repetitions). The low tempo RE (LTRE) session was performed using 50% 10RM with 3-0-3-0 seconds (concentric, pause, eccentric, and pause, respectively). The moderate tempo RE (MTRE) session was performed using 80% 10RM with 1-0-1-0 seconds (concentric, pause, eccentric, and pause, respectively). Affective valence (Feeling Scale), perceived activation (FAS), attentional focus, and ratings of perceived exertion (Borg 6-20) were reported after each set. A two-way analysis of variance with repeated measures showed only a significant main effect of the set (all ps < 0.05), indicating changes between sets but not between LTRE and MTRE. In addition, a paired-samples t-test did not find significant differences between LTRE and MTRE, on average, in any psychophysiological responses (all ps > 0.16). Thus, for the protocol tested, there is no psychophysiological advantage to using either LTRE or MTRE in novice men. From a practical perspective, for psychophysiological responses, the present results suggest that it is up to the trainer/coach to decide which RE movement tempo to use, which will depend on the purpose of the training period, specificity, client tolerance of and preference for exercise intensity, and movement tempo.

Mental fatigue impairs time trial performance in sub-elite under 23 cyclists

PURPOSE

This study investigates the effect of a mentally demanding response inhibitory task on time trial performance in sub-elite under 23 cyclists.

METHODS

Ten under 23 road cyclists completed two separate testing sessions during which they performed two different cognitive tasks before completing a 30-min time trial on the cycle ergometer. In the experimental condition, 30 min of a standard cognitive task (Stroop task) was used to elicit mental fatigue; in the control condition, a non-demanding activity was carried out. Subjective workload and mood were measured before and after the treatments, and motivation was recorded before the time-trial. During the time trial, power, cadence, heart rate, and rate of perceived exertion were assessed. Blood lactate concentrations and heart rate variability (using the root mean square of the successive differences) were measured before and after the time trial.

RESULTS

The Stroop task was rated more mentally (P < 0.001) and temporally (P < 0.001) demanding, effortful (P < 0.001), and frustrating (P = 0.001) than the control task; fatigue (P = 0.002) and vigor (P = 0.018) after the cognitive tasks were respectively higher and lower than in the control task. Mean power output (P = 0.007) and cadence (P = 0.043) were negatively affected by the Stroop task, while heart rate (P = 0.349), rating of perceived exertion (P = 0.710), blood lactate concentration (P = 0.850), and root mean square of the successive differences (P = 0.355) did not differ between the two conditions.

CONCLUSION

A mentally demanding activity reduced the subsequent physical performance in sub-elite under 23 cyclists. Thus, avoiding cognitive efforts before training and races could improve performance of high-level athletes.

Development and Feasibility of a Regulated, Supramaximal High-Intensity Training Program Adapted for Older Individuals

Background: High-intensity training (HIT) with extremely short intervals (designated here as supramaximal HIT) is a time-efficient training method for health and performance. However, a protocol for regulation and control of intensity is missing, impeding implementation in various groups, such as older individuals.

Methods: This study presents the development and characteristics of a novel training protocol with regulated and controlled supramaximal intervals adapted for older people. Using both quantitative and qualitative analyses, we explored the feasibility of the program, performed in a group training setting, with physically active older individuals (aged 65–75, n = 7; five women). The developed supramaximal HIT program consisted of 10 × 6 s cycle sprint intervals with ∼1 min of active recovery with the following key characteristics: (1) an individual target power output was reached and maintained during all intervals and regulated and expressed as the percentage of the estimated maximum mean power output for the duration of the interval (i.e., 6 s); (2) pedaling cadence was standardized for all participants, while resistance was individualized; and (3) the protocol enabled controlled and systematic adjustments of training intensity following standardized escalation criteria.

Aim: Our aim was to test the feasibility of a novel training regimen with regulated and controlled supramaximal HIT, adapted for older people. The feasibility criteria for the program were to support participants in reaching a supramaximal intensity (i.e., power output > 100% of estimated VO₂ max), avoid inducing a negative affective response, and have participants perceive it as feasible and acceptable.

Results: All feasibility criteria were met. The standardized escalation procedure provided safe escalation of training load up to a supramaximal intensity (around three times the power output at estimated VO₂ max). The participants never reported negative affective responses, and they perceived the program as fun and feasible.

Conclusion: This novel program offers a usable methodology for further studies on supramaximal HIT among older individuals with different levels of physical capacity. Future research should explore the effects of the program in various populations of older people and their experiences and long-term adherence compared with other forms of training.

Introducing a Dynamic Workstation in the Office: Insights in Characteristics of Use and Short-Term Changes of Well-Being in a 12 Week Observational Study

The present field study evaluates the use of dynamic workstations (cycling devices) in a real-life office environment. Specific characteristics of use were recorded and possible relationships with short-term changes in well-being were investigated. For a period of 12 weeks, 36 employees were given free access to eight devices. Frequency, duration and speed of use were self-determined but registered objectively for every event of use. Immediately before and after using a cycling device, employees rated their well-being with a modified version of the EZ-scale from Nitsch to assess changes in the short-term. In total, 817 events of use were registered. On each day of the intervention period one of the devices was used. Participants used the devices between one day to all days present at the office, for 21.09 (SD 0.58) to 31.58 (SD 2.19) minutes on average per event of use per day. Comparing the pre- and post-measurements, a significant increase in well-being after using a cycling device was found. Results of a Generalized Estimating Equations (GEE) analysis showed mixed effects for the duration of use, the speed and variation of speed on the probability of reporting positive changes in recovery, calmness and mood. Therefore, using cycling devices in the office might improve short-term well-being.

Saddle Height and Cadence Effects on the Physiological, Perceptual, and Affective Responses of Recreational Cyclists

Saddle height influences cycling performance and would be expected to influence cyclists physically, perceptually, and emotionally. We investigated how different saddle positions and cadences might affect cyclists’ torque, heart rate, rate of perceived exertion (RPE), and affective responses (Feeling scale). Nine male recreational cyclists underwent cycling sessions on different days under different conditions with a constant load. On Day 1, the saddle was at the reference position (109% of the distance from the pubic symphysis to the ground), and on Days 2 and 3, the saddle was in the “upward position” (reference + 2.5%) and “downward position” (reference − 2.5%) in random order. Each session lasted 30 minutes and was divided into three cadence-varied 10-minute stages without interruption: (a) freely chosen cadence (FCC), (b) FCC − 20%, and (c) FCC + 20%. We assessed all dependent measures at the end of each 10 minute stage. While there was no significant interaction (Saddle × Cadence) for any of the analyzed variables, torque values were higher at lower cadences in all saddle configurations, and the FCC + 20% cadence was associated with faster heart rate, higher RPE, and lower affect compared with FCC and FCC − 20% in all saddle positions. At all cadences, the saddle at “downward position” generated a higher RPE compared with “reference position” and “upward position.” The affective response was lower in the “downward position” compared with the “reference position.” Thus, while cyclists perceived the downward (versus reference) saddle position as greater exercise effort, they also associated it with unpleasant affect.

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.