Flavanol-rich cocoa consumption enhances exercise-induced executive function improvements in humans

Essential amino acid supplements ingestion has a positive effect on executive function after moderate-intensity aerobic exercise

Aerobic exercise acutely improves cognitive function (e.g., executive function (EF); memory recognition (MR)) and increases circulating brain-derived neurotrophic factor (BDNF). In addition, branched-chain amino acids (BCAA) ingestion acutely shortens the choice reaction time and increases brain BDNF. We examined whether the ingestion of essential amino acid (EAA) supplements (mainly composed of BCAA) would positively impact on cognitive function and circulating BDNF after moderate-intensity aerobic exercise. Twenty-two healthy young men received either an EAA supplements or the placebo (PL) 30 min before undergoing aerobic exercise. The participants performed a cycling exercise at 60% of peak oxygen uptake for 30 min. EF after aerobic exercise was better after the EAA treatment than after the PL treatment (P = 0.02). MR (P = 0.38 for response accuracy; P = 0.15 for reaction time) and circulating BDNF (P = 0.59) were not altered by EAA supplements. EF improvement was correlated with increases in some amino acids (leucine, isoleucine, valine, lysine, phenylalanine; all Ps < 0.05) that are potential substrates for synthesizing neurotransmitters in the brain. These results suggest that EAA supplements ingestion had a positive effect on EF after moderate-intensity aerobic exercise, while MR and BDNF were not altered.

How Healthy Is It to Fortify Cocoa-Based Products with Cocoa Flavanols? A Comprehensive Review

(1) Background: Cocoa's healthy benefits may be attributed to the potent antioxidant activity of cocoa polyphenols, mainly flavanols, which have been characterised as existing in a high concentration in cocoa. However, the phenolic composition of cocoa and cocoa-derived products is highly variable, and manufacturing processes might significantly reduce their phenolic content. For that reason, the full characterisation of cocoa and cocoa-derived products before evaluating their bioactivity is crucial. The aim of this review is to analyse the available evidence on the effect of flavanol-fortified cocoa-derived products on human health. (2) Methods: Forty-eight clinical trials focused on the health effect of consuming flavanol-fortified drinks, bars and chocolate have been reviewed, with a total of 1523 subjects. (3) Results: Although studies differ widely in methodology, dosage, duration, and target population, beneficial effects of flavanol-rich cocoa consumption have been observed at doses ranging from 45.3 mg/d to 1078 mg/d, especially on cardiovascular health and cognitive function. (4) Conclusions: Considering the high consumption and acceptability of cocoa and cocoa-derived products, the fortification of cocoa products as well as other highly consumed foods with cocoa flavanols could be an effective strategy for health promotion.

Executive function during exercise is diminished by prolonged cognitive effort in men

The speed and accuracy of decision-making (i.e., executive function (EF) domains) is an integral factor in many sports. At rest, prolonged cognitive load (pCL) impairs reaction time (RT). In contrast, exercise improves RT and EF. We hypothesized that RT and EF during exercise would be diminished by prolonged 'dual tasking' as a consequence of pCL. To test the hypothesis, twenty healthy male participants performed four conditions [resting control (Rest), pCL only (pCL_Rest), exercise only (EX), and pCL + exercise (pCL_EX)] in a randomized-crossover design. Both exercise conditions utilized a 50-min cycling exercise protocol (60% VO₂ peak) and the pCL was achieved via a 50-min colour-word Stroop task (CWST). Compared with Rest, pCL_Rest caused a slowed CWST RT (P < 0.05) and a large SD (i.e., intraindividual variability) of CWST RT (P < 0.01). Similarly, compared with EX, the slowed CWST RT (P < 0.05) and large SD of CWST RT (P < 0.01) were also observed in pCL_EX. Whereas the reverse-Stroop interference was not affected in pCL_Rest (P = 0.46), it was larger (i.e., declined EF) in pCL_EX than EX condition (P < 0.05). These observations provide evidence that the effort of pCL impairs RT and EF even during exercise.

Enhancing the Cognitive Effects of Flavonoids With Physical Activity: Is There a Case for the Gut Microbiome?

Age-related cognitive changes can be the first indication of the progression to dementias, such as Alzheimer’s disease. These changes may be driven by a complex interaction of factors including diet, activity levels, genetics, and environment. Here we review the evidence supporting relationships between flavonoids, physical activity, and brain function. Recent in vivo experiments and human clinical trials have shown that flavonoid-rich foods can inhibit neuroinflammation and enhance cognitive performance. Improved cognition has also been correlated with a physically active lifestyle, and with the functionality and diversity of the gut microbiome. The great majority (+ 90%) of dietary flavonoids are biotransformed into phytoactive phenolic metabolites at the gut microbiome level prior to absorption, and these prebiotic flavonoids modulate microbiota profiles and diversity. Health-relevant outcomes from flavonoid ingestion may only be realized in the presence of a robust microbiome. Moderate-to-vigorous physical activity (MVPA) accelerates the catabolism and uptake of these gut-derived anti-inflammatory and immunomodulatory metabolites into circulation. The gut microbiome exerts a profound influence on cognitive function; moderate exercise and flavonoid intake influence cognitive benefits; and exercise and flavonoid intake influence the microbiome. We conclude that there is a potential for combined impacts of flavonoid intake and physical exertion on cognitive function, as modulated by the gut microbiome, and that the combination of a flavonoid-rich diet and routine aerobic exercise may potentiate cognitive benefits and reduce cognitive decline in an aging population, via mechanisms mediated by the gut microbiome. Mechanistic animal studies and human clinical interventions are needed to further explore this hypothesis.

Mental Performance and Sport: Caffeine and Co-consumed Bioactive Ingredients

The plant defence compound caffeine is widely consumed as a performance enhancer in a sporting context, with potential benefits expected in both physiological and psychological terms. However, although caffeine modestly but consistently improves alertness and fatigue, its effects on mental performance are largely restricted to improved attention or concentration. It has no consistent effect within other cognitive domains that are important to sporting performance, including working memory, executive function and long-term memory. Although caffeine's central nervous system effects are often attributed to blockade of the receptors for the inhibitory neuromodulator adenosine, it also inhibits a number of enzymes involved both in neurotransmission and in cellular homeostasis and signal propagation. Furthermore, it modulates the pharmacokinetics of other endogenous and exogenous bioactive molecules, in part via interactions with shared cytochrome P450 enzymes. Caffeine therefore enjoys interactive relationships with a wide range of bioactive medicinal and dietary compounds, potentially broadening, increasing, decreasing, or modulating the time course of their functional effects, or vice versa. This narrative review explores the mechanisms of action and efficacy of caffeine and the potential for combinations of caffeine and other dietary compounds to exert psychological effects in excess of those expected following caffeine alone. The review focusses on, and indeed restricted its untargeted search to, the most commonly consumed sources of caffeine: products derived from caffeine-synthesising plants that give us tea (Camellia sinensis), coffee (Coffea genus), cocoa (Theabroma cacao) and guaraná (Paullinia cupana), plus multi-component energy drinks and shots. This literature suggests relevant benefits to mental performance that exceed those associated with caffeine for multi-ingredient energy drinks/shots and several low-caffeine extracts, including high-flavanol cocoa and guarana. However, there is a general lack of research conducted in such a way as to disentangle the relative contributions of the component parts of these products.

Impact of Inter-Set Short Rest Interval Length on Inhibitory Control Improvements Following Low-Intensity Resistance Exercise in Healthy Young Males

The length of rest interval between sets (i.e., inter-set rest interval) is an important variable for resistance exercise program. However, the impact of the inter-set rest interval on improvements in cognitive function following resistance exercise remains unknown. In this study, we compared the effect of short rest interval (SRI) vs. long rest interval (LRI) protocols on post-exercise cognitive inhibitory control (IC) improvements induced by low-intensity resistance exercise. Twenty healthy, young males completed both SRI and LRI sessions in a crossover design. The bilateral knee extensor low-intensity resistance exercise was programed for six sets with 10 repetitions per set using 40% of one-repetition maximum. The inter-set rest interval lengths for SRI and LRI protocols were set for 1 and 3min, respectively. The color-word Stroop task (CWST) was administrated at six time points: baseline, pre-exercise, immediate post-exercise, and every 10min during the 30-min post-exercise recovery period. The levels of blood lactate, which may be an important determinant for improving IC, throughout the 30-min post-exercise recovery period were significantly higher following SRI protocol than following LRI protocol (p=0.002 for interaction effect). In line with this result, large-sized decreases in the reverse-Stroop interference score, which represent improved IC, were observed immediately after SRI protocol (d=0.94 and 0.82, respectively, vs. baseline and pre-exercise) as opposed to the moderate-sized decreases immediately after LRI protocol (d=0.62 and 0.66, respectively, vs. baseline and pre-exercise). Moreover, significant decreases in the reverse-Stroop interference score were observed from 10 to 30min after SRI protocol (all ps<0.05 vs. baseline and/or pre-exercise), whereas no such decrease was observed after LRI protocol. Furthermore, the degree of decreases in the reverse-Stroop interference score throughout the 30-min post-exercise recovery period was significantly greater in SRI protocol than in LRI protocol (p=0.046 for interaction effect). We suggest that the SRI protocol is more useful in improving post-exercise IC, potentially via greater circulating lactate levels, compared to the LRI protocol. Therefore, the inter-set rest interval length may be an important variable for determining the degree of cognitive function improvements following resistance exercise in healthy young males.

Similar improvements in cognitive inhibitory control following low-intensity resistance exercise with slow movement and tonic force generation and high-intensity resistance exercise in healthy young adults: a preliminary study

This study compared the effects of low-intensity resistance exercise with slow movement and tonic force generation (ST-LRE) and high-intensity resistance exercise (HRE) on post-exercise improvements in cognitive inhibitory control (IC). Sixteen young males completed ST-LRE and HRE sessions in a crossover design. Bilateral knee extensor ST-LRE and HRE (8 repetitions/set, 6 sets) were performed with 50% of one-repetition maximum with slow contractile speed and 80% of one-repetition maximum with normal contractile speed, respectively. The IC was assessed using the color-word Stroop task at six time points: baseline, pre-exercise, immediate post-exercise, and every 10 min during the 30-min post-exercise recovery period. The blood lactate response throughout the experimental session did not differ between ST-LRE and HRE (condition × time interaction P = 0.396: e.g., mean ± standard error of the mean; 8.1 ± 0.5 vs. 8.1 ± 0.5 mM, respectively, immediately after exercise, P = 0.983, d = 0.00). Large-sized decreases in the reverse-Stroop interference scores, which represent improved IC, compared to those before exercise (i.e., baseline and pre-exercise) were observed throughout the 30 min post-exercise recovery period for both ST-LRE and HRE (decreasing rate ≥ 38.8 and 41.4%, respectively, all ds ≥ 0.95). The degree of post-exercise IC improvements was similar between the two protocols (condition × time interaction P = 0.998). These findings suggest that despite the application of a lower exercise load, ST-LRE improves post-exercise IC similarly to HRE, which may be due to the equivalent blood lactate response between the two protocols, in healthy young adults.

Effect of very low-intensity resistance exercise with slow movement and tonic force generation on post-exercise inhibitory control

Background

The extremely low loads (e.g., <30% of one-repetition maximum) involved in performing resistance exercise are effective in preventing musculoskeletal injury and enhancing exercise adherence in various populations, especially older individuals and patients with chronic diseases. Nevertheless, long-term intervention using this type of protocol is known to have little effects on muscle size and strength adaptations. Despite this knowledge, very low-intensity resistance exercise (VLRE) with slow movement and tonic force generation (ST) significantly increases muscle size and strength. To further explore efficacy of ST-VLRE in the clinical setting, this study examined the effect of ST-VLRE on post-exercise inhibitory control (IC).

Methods

Twenty healthy, young males (age: 21 ± 0 years, body height: 173.4 ± 1.2 cm, body weight: 67.4 ± 2.2 kg) performed both ST-VLRE and normal VLRE in a crossover design. The load for both protocols was set at 30% of one-repetition maximum. Both protocols were programmed with bilateral knee extension for six sets with ten repetitions per set. The ST-VLRE and VLRE were performed with slow (3-sec concentric, 3-sec eccentric, and 1-sec isometric actions with no rest between each repetition) and normal contractile speeds (1-sec concentric and 1-sec eccentric actions and 1-sec rests between each repetition), respectively. IC was assessed using the color-word Stroop task at six time points: baseline, pre-exercise, immediate post-exercise, and every 10 min during the 30-min post-exercise recovery period.

Results

The reverse-Stroop interference score, a parameter of IC, significantly decreased immediately after both ST-VLRE and VLRE compared to that before each exercise (decreasing rate >32 and 25%, respectively, vs. baseline and/or pre-exercise for both protocols; all Ps < 0.05). The improved IC following ST-VLRE, but not following VLRE, remained significant until the 20-min post-exercise recovery period (decreasing rate >48% vs. baseline and pre-exercise; both Ps < 0.001). The degree of post-exercise IC improvements was significantly higher for ST-VLRE than for VLRE (P = 0.010 for condition × time interaction effect).

Conclusions

These findings suggest that ST-VLRE can improve post-exercise IC effectively. Therefore, ST-VLRE may be an effective resistance exercise protocol for improving cognitive function.

Blood Flow Restriction Improves Executive Function after Walking

PURPOSE

Blood flow restriction (BFR) walking is recognized as a beneficial strategy for increasing skeletal muscle mass and strength. No study has examined the effect of BFR exercise on cognitive functions, including executive function (EF). In this study, we examined the effect of BFR walking on EF.

METHODS

We performed two studies, at rest and exercise, with BFR or non-BFR (NBFR) in a crossover design. Sitting rest was performed for 15 min (study 1, n = 8). Exercise was programmed at five sets of 2-min walking at 5 km·h with 1-min rest intervals (study 2, n = 16). The BFR condition was achieved using 200 mm Hg pressure cuffs placed around the proximal region of the thighs. The NBFR condition involved no pressure cuffs. EF was assessed using the color-word Stroop task before and after each condition.

RESULTS

In study 1, there were no significant effects on EF parameters for both BFR and NBFR conditions, suggesting that BFR alone does not improve EF. In study 2, incongruent reaction time shortened after BFR walking compared with that before walking (P = 0.001). Furthermore, the reverse Stroop interference score decreased after BFR walking compared with that before walking (P < 0.001).

CONCLUSION

These findings suggest that, even with a mild exercise, BFR walking improves EF independently of the effect of BFR alone or walking alone.

Effect of Cocoa and Cocoa Products on Cognitive Performance in Young Adults

Increasing evidence support a beneficial role of cocoa and cocoa products on human cognition, particularly in aging populations and patients at risk. However, thorough reviews on the efficacy of cocoa on brain processes in young adults do not exist precisely due to the limited number of studies in the matter. Thus, the aim of this study was to summarize the findings on the acute and chronic effects of cocoa administration on cognitive functions and brain health in young adults. Web of Science and PubMed databases were used to search for relevant trials. Human randomized controlled studies were selected according to PRISMA guidelines. Eleven intervention studies that involved a total of 366 participants investigating the role of cocoa on cognitive performance in children and young adults (average age ≤ 25 years old) were finally selected. Findings from individual studies confirm that acute and chronic cocoa intake have a positive effect on several cognitive outcomes. After acute consumption, these beneficial effects seem to be accompanied with an increase in cerebral blood flow or cerebral blood oxygenation. After chronic intake of cocoa flavanols in young adults, a better cognitive performance was found together with increased levels of neurotrophins. This systematic review further supports the beneficial effect of cocoa flavanols on cognitive function and neuroplasticity and indicates that such benefits are possible in early adulthood.

Effect of repeated bouts versus a single bout of moderate-intensity exercise on postexercise inhibitory control

We previously demonstrated that duration of aerobic exercise plays an important role in improving cognitive inhibitory control (IC). Repeated bouts of aerobic exercise (R-EX), which are performed with a rest interval, is a useful strategy in improving physical health parameters in similar manners to a single bout of aerobic exercise (S-EX). However, whether R-EX would be effective in improving IC remains unknown. This study compared the effect of R-EX versus S-EX of moderate-intensity exercise on postexercise IC. Twenty healthy, young males performed both R-EX and S-EX in a crossover design. R-EX consisted of two 20-min moderate-intensity bouts (60% of peak oxygen consumption) for 20 min, which were separated by a 20-min rest interval. S-EX consisted of a once-off 40-min moderate-intensity bout without rest interval. To evaluate IC, the color-word Stroop task was administered before exercise, immediately after exercise, and every 10 min during the 30-min postexercise recovery period. The reverse-Stroop interference score, which is a parameter of IC, significantly decreased immediately after both R-EX and S-EX compared with that before each exercise (both Ps < 0.05). The degree of changes in IC following exercise did not differ between the two protocols. By contrast, the results of the present study showed that R-EX may have more beneficial effects on cardiac and perceptual responses than S-EX. Therefore, the present study determined that R-EX changes postexercise IC similar to S-EX. We suggest that R-EX can be used as safe and effective exercise protocol to improve cognitive function in various populations.

Work volume is an important variable in determining the degree of inhibitory control improvements following resistance exercise

We previously determined that improvement in cognitive inhibitory control (IC) immediately after localized resistance exercise was greater for high-intensity resistance exercise (HRE) than for low-intensity resistance exercise (LRE). However, our previous study used the same total repetitions (i.e., same repetitions per set) between HRE and LRE; therefore, the difference in postexercise IC improvement might be due to a difference in work volume (i.e., intensity × total repetitions). In this study, we compared the effect of high-volume (HV)-LRE to that of volume-matched HRE on postexercise IC improvements. Twenty-two healthy, young males performed both HV-LRE and HRE in a crossover design. Exercise loads for HV-LRE and HRE were set at 35% and 70% of one-repetition maximum, respectively. The bilateral knee extension exercises for HV-LRE and HRE were programmed for six sets with 20 and 10 repetitions, respectively, per set. IC was measured using the color-word Stroop task (CWST) at six time points; baseline, pre-exercise, immediate postexercise, and every 10 min during the 30-min postexercise recovery period. The reverse-Stroop interference score decreased significantly immediately after HV-LRE and HRE compared with that before each exercise (decreasing rate >34 and >38%, respectively, vs. baseline and pre-exercise; all ps < .05), and the decreased score remained significant until 20 min after both protocols (decreasing rate >40 and >38%, respectively, vs. baseline and pre-exercise; all ps < .05). The degree of the postexercise IC improvements did not differ significantly between the two protocols. These findings suggest that HV-LRE improves IC in a similar manner to volume-matched HRE.

Phytochemicals for Improving Aspects of Cognitive Function and Psychological State Potentially Relevant to Sports Performance

Subjective alertness and optimal cognitive function, including in terms of attention, spatial/working memory and executive function, are intrinsic to peak performance in many sports. Consumption of a number of plant-derived ‘secondary metabolite’ phytochemicals can modulate these psychological parameters, although there is a paucity of evidence collected in a sporting context. The structural groups into which these phytochemicals fall—phenolics, terpenes and alkaloids—vary in terms of the ecological roles they play for the plant, their toxicity and the extent to which they exert direct effects on brain function. The phenolics, including polyphenols, play protective roles in the plant, and represent a natural, benign component of the human diet. Increased consumption has been shown to improve cardiovascular function and is associated with long-term brain health. However, whilst short-term supplementation with polyphenols has been shown to consistently modulate cerebral blood-flow parameters, evidence of direct effects on cognitive function and alertness/arousal is currently comparatively weak. Terpenes play both attractant and deterrent roles in the plant, and typically occur less frequently in the diet. Single doses of volatile monoterpenes derived from edible herbs such as sage (Salvia officinalis/lavandulaefolia) and peppermint (Mentha piperita), diterpene-rich Ginkgo biloba extracts and triterpene-containing extracts from plants such as ginseng (Panax ginseng/quinquefolius) and Bacopa monnieri have all been shown to enhance relevant aspects of cognitive function and alertness. The alkaloids play toxic defensive roles in the plant, including via interference with herbivore brain function. Whilst most alkaloids are inappropriate in a sporting context due to toxicity and legal status, evidence suggests that single doses of nicotine and caffeine may be able to enhance relevant aspects of cognitive function and/or alertness. However, their benefits may be confounded by habituation and withdrawal effects in the longer term. The efficacy of volatile terpenes, triterpene-rich extracts and products combining low doses of caffeine with other phytochemicals deserves more research attention.

The Impact of Epicatechin on Human Cognition: The Role of Cerebral Blood Flow

Epicatechin is a monomeric flavanol found in food sources such as tea, apples, berries and cocoa. A number of large-scale epidemiological studies have demonstrated an association between the consumption of these foods and cognitive function, as well as improved blood flow. The aim of this review is to summarise the evidence from intervention studies to clarify the effect of epicatechin on cognition and to consider the role of increased cerebral blood flow as a mechanism for any effects. The effects of epicatechin as consumed in cocoa are, therefore, reviewed here as this represents the only dietary source where it is purported to be the major active component. Our main findings are that a) the positive modulation of tasks that involve memory, executive function and processing speed in older adults; b) the cognitive benefits are more often shown in studies containing more than 50 mg epicatechin/day; and c) all studies with a duration of 28 days or longer in populations >50 years old demonstrate a cognitive improvement. However, as highlighted by this review, it is not currently possible to attribute effects solely to epicatechin without consideration of synergies. In order to overcome this issue, further studies examining the cognitive effects of epicatechin in isolation are required. The role of cerebral blood flow also requires further investigation through simultaneous measurement alongside cognitive function.

Self-selected music-induced reduction of perceived exertion during moderate-intensity exercise does not interfere with post-exercise improvements in inhibitory control

Acute aerobic exercise improves inhibitory control (IC). This improvement is often associated with increases in perceived exertion during exercise. However, listening to music during aerobic exercise mitigates an exercise-induced increase in perceived exertion. Thus, it is hypothesized that such effects of music may interfere with exercise-induced improvements in IC. To test this hypothesis, we examined the effect of music on post-exercise IC improvements that were induced by moderate-intensity exercise. Fifteen healthy young men performed cycle ergometer exercise with music or non-music. The exercise was performed using a moderate-intensity of 60% of VO_{2 peak} for 30 min. The music condition was performed while listening to self-selected music. The non-music condition involved no music. To evaluate IC, the Stroop task was administered before exercise, immediately after exercise, and during the 30-min post-exercise recovery period. The rate of perceived exertion immediately before moderate-intensity exercise completed was significantly lower in music condition than in non-music condition. The IC significantly improved immediately after exercise and during the post-exercise recovery period compared to before exercise in both music and non-music conditions. The post-exercise IC improvements did not significantly differ between the two conditions. These findings indicate that self-selected music-induced mitigation of the increase in perceived exertion during moderate-intensity exercise dose not interfere with exercise-induced improvements in IC. Therefore, we suggest that listening to music may be a beneficial strategy in mitigating the increase in perceived exertion during aerobic exercise without decreasing the positive effects on IC.