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Effects of matcha extract on simple and complex reaction times


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This study analysed the effect of a food supplement, matcha tea extract, on simple and complex reaction time. The main objective was to verify the positive effect of this product on the speed of reaction to a visual stimuli after the extract was given. After the extract was given, selected individuals (n=31) were tested for simple and complex reaction time performance. A double blind experiment method with an added placebo was used to obtain the results. Statistical analysis included the Wilcoxon test to analyse the effect of the extract. The majority of study participants showed a statistical significant difference for the measured variables of both complex and simple reaction times. The results confirmed the positive influence of matcha extract on the reaction time of the studied individuals. This suggests that this nutritional supplement is suitable for lowering either the simple or complex response time after a visual stimuli is presented.
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Matcha extract effects on simple and complex reaction time
University of J. E. Purkyně, Faculty of Education, Ústí nad Labem, Czech Republic
This study analysis the effect of a food supplement Matcha tea extract, its effects on
simple and complex reaction time. The main objective of the analysis was to verify the
positive effect of this product on organism mainly in the area of the speed of organism
reaction to a visual stimuli after the extract was applied.
After the test substance was applied, selected individuals (n=31) were tested for simple
and complex reaction time performance. Double blind experiment method with added
placebo was used in order to find satisfactory results.
Statistical analysis then followed in which the recorded data sample went through the
Wilcoxon test to analyse the substance effect. Majority of probands manifested
significant difference practically and statistically in measured variables of both complex
and reaction time.
The study results proved the influence of Matcha extract effect on the reaction time of
the observed individuals and thus suggest that this nutrition supplement is suitable for
lowering the time response after a visual stimuli occurring either for simple and
complex reaction.
Key words: Simple reaction, complex reaction, matcha, Wilcoxon test
The matcha (抹茶 in jap.) extract has been known for more than a millennium, first
recorded traces of which date back to the 12th century China and Japan. In Japanese
then such type of extract is called Tencha (てんちゃ, 点茶) and is commonly used
during traditional tea ceremonies. Matt () in Japaneese means crushed into a powder,
which preserves all the active substances (Thoma, 2014). Depending on the batch the
amount of the active substance can differ up to 10%. Main reason for this is the
collection of the tea during harvest. Such composition is typical for matcha which has
enough „delicacy“, which means that the more delicacy the higher quality of matcha
tea. Matcha contains twice as much caffeine and 4 times more amount of L-theanine
amino acid than any other green tea known to mankind (Standard Tables of Food
Composition, 2012). Negative effects of matcha have not yet been described, however
there are 35 mg of active substance
One gram of tea including the daily recommended dose should not exceed 400mg of the
active substance. That is equal to 12 cups of tea (Haskell, Kennedy, Milne, Wesnes, &
Scholey, 2008; Weiss & Anderton, 2003).
Haskell (Haskell et al., 2008) states that L-theanine can be found mainly in tea and as
well as caffeine. In his study he analysed cognitive effects of this amino acid in
combination with caffeine. The results showed that caffeine leads to faster reaction in
terms of number perception, better RVIP (Rapid visual information processing) and the
reduction of the fatigue effect. Combination of RVIP and decrease of psychological
fatigue leads towards faster reaction time, faster working memory and better sentence
verification accuracy. According to the results of Haskell’s study, the intensity of
headaches also decreased. Such facts suggest that beverages containing caffeine and L-
theanine at the same time can have different pharmacological profile than such
substances which contain only caffeine. Caffeine itself helped increase the reaction
speed, information processing accuracy, simple reaction time and RVIP, numeric
definition of the reaction time of the working memory, reaction time of the delayed
word recognition. Sentence recognition was then more accurate when both substances
were used at the same time.
One study concerning the catechin amounts in green tea using electronic
chromatography, pointed out that green tea contains high amounts of Epigallocatechin
gallate (EGCG). This catechin is one of the most effective antioxidants and its effects
can prevent cancer. EGCG levels in matcha exceed several times the amount of the
same substance in ordinary green tea (Weiss & Anderton, 2003). Quinlan, King, Hanna
and Ghazziudin (1997) came with a finding, that tea containing 100mg of caffeine had
significantly stronger effects than coffee with the same amount of caffeine. Steptoe,
Hamer a Chida (2007) found, that tea is able to decrease the activation of platelets and
cortisol levels during stress reaction and also that tea helps increase feeling of relaxation
and body control.
Kakuda (2000) during his animal testing proved that is capable of stimulation inhibition
caused by caffeine during EEG scan of spontaneous animal activity.
Lu, Guarnieri and Simon (2004) studies the subjective mood effects of L-theanine and
found that 200mg of the substance can increase the feeling of “peace in mind”.
Kobayashi, Heck, Nomura, Horiuchi (1998) found, that 200 mg of L-theanine leads to
increase of alpha brain waves, which suggests that this substance is good for relaxation
without fatigue and may decrease reaction time to a specific degree. From available
sources we then may conclude that matcha tea contains beneficial substances which
have positive effect on human body. The beneficial substances are amino acids, anti-
oxidants, vitamins (C, B1, B2…) and minerals (potassium, sodium, calcium, etc.).
Matcha tea has many good effects on overall health, such as helps lower the cholesterol
and sugar levels in bloodstream, supports blood vessel structure, as well heart and
overall blood circulation. Matcha contains high amount of polyphenol catechin which
are very effective against many diseases and this effect does not only include EGCF.
Study conducted by Weiss and Andertona (2003) found, that it is matcha tea, which had
several times higher amount of EGCG than in regular types of green tea. The study also
pointed to the fact, that caffeine as itself can lead to reaction time decrease, however
combined with L-thiamine, supporting good mood, alpha waves and anxiety relief, can
thus decrease the overall reaction time possibly even more (Haskell et al., 2008).
On the other hand the effects of matcha tea have been verified in terms of fragile
hypotheses based on specific analyses, method and factors which in some cases assured
positive or negative effect of this extract. That is why we decided to contribute to the
canon of research to add more to the solution of the extract effect.
Test subject group description
This study is concerned with the possible increase of individual’s reaction skills while
using nutrition supplements in this case, matcha extract. The main objective it to find,
whether after its consumption reaction skills get better, as sources regarding this subject
suggest. This study is then an additional contribution to the already existing canon of
nutrition supplement studies, and thus verify that matcha extract functions as a
stimulant, which can prepare human organism for faster responses to a selected
stimulus. The study was attended by 31 probands (15 women, 16 men) ages 20 45
(table 1.), based on two measurements during one week. All probands were in good
physical shape and healthy during testing without any subjective issues, however
kinesiology analysis of test subjects was not included in the study. The overall data
sample was done via purposeful selection.
Table 1. Basic description of the test subject group
Legend: SD - standard deviation
The testing procedure has been done twice, always a week in between each testing
taking place. Each individual had to abstain from drinking or using any substances
which may cause any cognitive arousal (e.g. caffeine etc.) for 48 hours and were
advised not to engage in any difficult physical activity before testing as well. The
testing then involved double blind test. Each probands randomly took prepared sample
(capsule) of substances labelled A, or B. Sample A contained 35 of matcha and
sample B contained the same amount of placebo (starch). The amount of substance dose
had to be adjusted according to test subject’s weight. After 50 minutes from the
swallowing of the capsule each subject was tested via reactimeter to measure simple and
subsequently complex reaction time. After a week, second testing took place, during
which probands took an opposite label capsule than previous week. All measurements
took place in a standard environment in KTVS UJEP laboratories in Ústí nad Labem
based on recommendation of a study conducted by Balkó (Balkó, Wasik, Chytrý,
Dunajová a Škopek, 2017).
In order to measure simple reaction time to a visual stimulus, test subjects were seated
in an immobile chair opposite a chair (eyes positioned 60cm horizontally from the
computer screen). The plate for reaction time testing was placed under either right, or
left hand depending on the preference of the test subject. The hand was placed 4 cm
above the touch-sensitive plate. Test subjects were facing the computer screen and
observed a green circle symbol in the middle of the screen on a white background which
appeared in different intervals. Each appearance of the symbol meant that test subject
had to react to it by touching the sensitive plate 20 times in row. For complex reaction
time measurement we used four different plates and four symbols on the screen, Test
subject had to react to a specific symbol by pressing the related plate, again, 20 times in
a row. The plates were positioned in a square setting with a 4 cm gap in between each
plate. The first plate was for the red square, second one dot green circle, third plate
represented blue triangle and the fourth yellow cross. Like in the previous testing of
simple reaction time, the stimulus always appeared in the centre of the screen. This test
regarded the use of both hands with the default positioning of hand, which was 4cm
above the workspace, left hand 3cm away front he left plates and right hand 3 cm away
from the right plates.
For the purpose of reaction skill measurement, special reactimeter and Fitro Agility
Check & Reaction 2.0 (Fitronic, s. r. o.) software was used. The software is able to
generate stimuli in a range between 500-3000 Ms, project them on a computer screen
and recorded the reaction time of a test subject (plate press). Error attempts were not
included in the analysis. Simple reaction time threshold range of correct attempt was
calculated to be spectrum between 100-1500 Ms, complex reaction time then has
threshold range of 150-2000 Ms. All participants were not disturbed by any external
stimuli during testing.
Data normality was tested via Shapiro-Wilks test. The results of simple and complex
reaction time do not have normal data distribution and that is why nonparametric
Pic. 1 Simple reaction time
Statistical methods have to be applied in the analysis.
In order to statistically process the nonparametric data set, Wilcoxon test is suitable,
because it compares dependent selections. The effect size threshold was set to p < 0, 05.
In order to calculate the effect size, Rosenthal coefficient r (Rosenthal, 1994) was used,
which sets effect intervals in a following spectrum:
small effect (r > 0,1)
Moderate effect (r > 0,3)
Significant effect (r > 0,5)
This chapter describes the outcomes and results of the reactimeter testing showed via
software tools described above. Picture 1.shows measurements of simple reaction times
(medians) of individual probands after matcha extract and placebo consumption. Picture
2. Than shows reaction time levels of each test subject.
Pic. 2 Complex reaction time
Out of all measured samples of SRT (simple reaction time) after matcha extract and
placebo, the analysis showed (Tab. 3) there exists a significant difference (p´0, 00; r=0,
56). The analysis of CRT (complex reaction time) found, that there is also a significant
difference between matcha tea extract and placebo (p = 0, 00; r = 0, 34). The effect size
of SRT (56%) is higher than within complex reaction time (34%)
Tab. 1 Reaction time after placebo and matcha tea extract consumption
SRT simple reaction time, CRT complex reaction time, p error probability after
zero hypothesis rejection, r effect size
The following picture (Pic. 3) shows differences in SRT after matcha extract, after
placebo consumption. Such differences can be seen also in CRT, after the consumption
of placebo (Picture 4.).
Pic. 3 Simple reaction time after matcha extract and placebo consumption
Pic. 4 Complex reaction time after matcha extract and placebo consumption
The results shown above describe the difference between SRT and CRT, the effect of
the analysed substance, which proved to manifest significant differences in reaction
time levels.
After the data processing, the analysis showed that statistically significant change can
be spotted among both of the observed variables of reaction time. Thus we may
conclude that among both simple and complex reaction time have been influenced by
decreasing the speed of reaction to 56%simple and 34 % of complex reaction time. For
this particular reason it is possible to induct, that matcha extract is able to decrease the
response time period to a visual stimuli for both simple and complex reaction time. The
analysis was however unsuccessful to be comparable with other studies in terms of its
results. It was, however, possible to compare similar articles regarding similar issues,
e.g. study conducted in 2003 testing the caffeine influence (Jensen et al., 2005), and
another study article written in 2010 which tested the taurine effects on RT (Škopek,
Hnízdil, 2010). Interesting to point out, is that among all of the previously mentioned
substances have no, proven effect, as the one showed in our study concerning matcha
extract, even though some manufacturers of supplements including the previously
mentioned substances say that caffeine and taurine have similar effects as matcha. We
are, of course, aware that our study results have to be read with a certain amount of
caution. The better reaction time levels may have been also caused by other variables
which influence performance such as individual psychological fitness etc. In order to
verify the results presented in our study, additional control (repeated) testing on the
same sample of probands would be required which may increase the reliability and
validity. Nevertheless, the findings in this study a\re more than impressive.
This article contribution set its objective to find out whether it is possible to influence
the reaction time of a person depending on the reaction to a visual stimulus after matcha
tea extract consumption. The results of the data analysis have shown that this nutrition
supplement has manifested signs of a stimulant during the testing of simple and
complex reaction time. After the consumption of the extract, in majority of cases the
predicted decrease of reaction time truly occurred. That is the main reason why we may
recommend the matcha extract as a suitable supplement for better and faster reactions to
visual stimuli, which can be of course used within a wide range of sport activities, or
also suitable for maintaining better reactions in every day, e.g. driving a vehicle etc.
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endurance in 75- yr-old citizens: a randomized, double-blind, placebo-comtroled,
crossover study. Journal Applied Physiology,.99(1), 2302-2306.
Lu, N., Guarnieri, D.J. & Simon, M.A. (2004). Localization of Tec29 to ring canals is
mediated by Src64 and PtdIns(3,4,5)P(3)-dependent mechanisms. Embo Journal,
23(5), 1089-110.
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Full-text available
This study examines the effects of a dietary supplement – Taurine during physical exercise. We have been trying to detect if this product's positive effects on human body mainly in the light of reaction velocity and stamina are as stated by the preparation producers. Upon the application, we measured participants' visual reaction velocity and thereafter the effects on their endurance abilities. We chose the modification of Conconi test for the evaluation. During the whole test we recorded participants' heart rate (HR), maximum heart rate (HRmax), maximal lung ventilation (VE), VO2 max, breathing frequency (BF) and maximal speed of a running machine. We statistically analysed the effects of taurine on human body from the outcomes. Most observed values do not show distinctive variations. The study reflects the fact that the dietary supplement Taurine does not influence either physical performance or reaction velocity as it is granted by producers.
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Saccharomyces cerevisiae carries approximately 150 copies of rDNA in tandem repeats. It was found that the absence of an essential subunit of RNA polymerase I (Pol I) in rpa135 deletion mutants triggers a gradual decrease in rDNA repeat number to about one-half the normal level. Reintroduction of the missing RPA135 gene induced a gradual increase in repeat number back to the normal level. Gene FOB1 was shown to be essential for both the decrease and increase of rDNA repeats. FOB1 was shown previously to be required for replication fork blocking (RFB) activity at RFB site in rDNA and for recombination hot-spot (HOT1) activity. Thus, DNA replication fork blockage appears to stimulate recombination and play an essential role in rDNA expansion/contraction and sequence homogenization, and possibly, in the instability of repeated sequences in general. RNA Pol I, on the other hand, appears to control repeat numbers, perhaps by stabilizing rDNA with the normal repeat numbers as a stable nucleolar structure.
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This study investigated the effect of caffeine on physical performance in healthy citizens aged > or =70 yr. The randomized, double-blind, placebo-controlled, crossover study was conducted in 15 men and 15 women recruited by their general practitioner. Participants abstained from caffeine for 48 h and were randomized to receive one capsule of placebo and then caffeine (6 mg/kg) or caffeine and then placebo with 1 wk in between. One hour after intervention, we measured reaction and movement times, postural stability, walking speed, cycling at 65% of expected maximal heart rate, perceived effort during cycling, maximal isometric arm flexion strength, and endurance. Analysis was by intention to treat, and P < 0.05 was regarded as significant. Caffeine increased cycling endurance by 25% [95% confidence interval (CI): 13-38; P = 0.0001] and isometric arm flexion endurance by 54% (95% CI: 29-83; P = 0.0001). Caffeine also reduced the rating of perceived exertion after 5 min of cycling by 11% (95% CI: 5-17; P = 0.002) and postural stability with eyes open by 25% (95% CI: 2-53; P = 0.03). Caffeine ingestion did not affect muscle strength, walking speed, reaction, and movement times. At the end of the study, 46% of participants correctly identified when they received caffeine and placebo. Caffeine increased exercise endurance in healthy citizens aged > or =70 yr, but the participants' reasons for stopping the test may have varied between subjects, as the cycling test was done at approximately 55% of maximal oxygen consumption. Further studies are required to investigate whether caffeine can be utilized to improve the physical performance of elderly citizens.
One hundred fifty adolescent inpatients with major depression were systematically assessed for demographic and clinical differences between psychotic and nonpsychotic depression. Delusions and/or hallucinations were present in 10% of the subjects. The psychotic group had significantly more frequent and severe suicidal ideation. Posttraumatic stress disorder was also more frequent in the psychotic group.
This paper reviews the function of the mitochondria and the mechanisms by which nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs) cause mitochondrial toxicity. Highly active antiretroviral therapy (HAART) reduces rates of morbidity and mortality due to HIV disease. However, long-term treatment with these drugs may be associated with adverse effects. Nucleoside and nucleotide analogues are potent inhibitors of HIV reverse transcriptase and have become the cornerstone of HAART. Unfortunately, these drugs have also been shown to inhibit cellular polymerases, most notably mitochondrial DNA polymerase gamma. Studies of the NRTIs in enzyme assays and cell cultures demonstrate the following hierarchy of mitochondrial DNA polymerase gamma inhibition: zalcitabine > didanosine > stavudine > lamivudine > zidovudine > abacavir. In vitro investigations have also documented impairment of the mitochondrial enzymes adenylate kinase and the adenosine diphosphate/adenosine triphosphate translocator. Inhibition of DNA polymerase gamma and other mitochondrial enzymes can gradually lead to mitochondrial dysfunction and cellular toxicity. The clinical manifestations of NRTI-induced mitochondrial toxicity resemble those of inherited mitochondrial diseases (ie, hepatic steatosis, lactic acidosis, myopathy, nephrotoxicity, peripheral neuropathy, and pancreatitis). Fat redistribution syndrome, or HIV-associated lipodystrophy, is another side effect attributed in part to NRTI therapy. The morphologic and metabolic complications of this syndrome are similar to those of the mitochondrial disorder known as multiple symmetric lipomatosis: suggesting that this too may be related to mitochondrial toxicity. The pathophysiology of less common adverse effects of nucleoside analogue therapy, such as diabetes, ototoxicity, and retinal lesions, may be related to mitochondrial dysfunction but have not been adequately studied. NRTls can block both HIV reverse transcriptase and mitochondrial DNA polymerase gamma. Inhibition of the latter enzyme is the most likely cause of the adverse effects associated with these drugs.
Catechins in green tea are known to have many beneficial health properties. Recently, it has been suggested that matcha has greater potential health benefits than other green teas. Matcha is a special powdered green tea used in the Japanese tea ceremony. However, there has been no investigation to quantitate the catechin intake from matcha compared to common green teas. We have developed a rapid method of analysis of five catechins and caffeine in matcha using micellar electrokinetic chromatography. Results are presented for water and methanol extractions of matcha compared with water extraction of a popular green tea. Using a mg catechin/g of dry leaf comparison, results indicate that the concentration of epigallocatechin gallate (EGCG) available from drinking matcha is 137 times greater than the amount of EGCG available from China Green Tips green tea, and at least three times higher than the largest literature value for other green teas.
Stress influences circulating inflammatory markers, and these effects may mediate the influence of psychosocial factors on cardiovascular risk and other conditions such as psoriasis and rheumatoid arthritis. Inflammatory responses can be investigated under controlled experimental conditions in humans, and evidence is beginning to emerge showing that circulating inflammatory factors respond to acute psychological stress under laboratory conditions. However, research published to date has varied greatly in the composition of study groups, the timing of samples, assay methods, and the type of challenge imposed. The purpose of this review is to synthesize existing data using meta-analytic techniques. Thirty studies met inclusion criteria. Results showed robust effects for increased levels of circulating IL-6 (r=0.19, p=0.001) and IL-1beta (r=0.58, p<0.001) following acute stress, and marginal effects for CRP (r=0.12, p=0.088). The effects of stress on stimulated cytokine production were less consistent. Significant variation in the inflammatory response was also related to the health status of participants and the timing of post-stress samples. A number of psychobiological mechanisms may underlie responses, including stress-induced reductions in plasma volume, upregulation of synthesis, or enlargement of the cell pool contributing to synthesis. The acute stress-induced inflammatory response may have implications for future health, and has become an important topic of psychoneuroimmunological research.
L-Theanine is an amino acid found naturally in tea. Despite the common consumption of L-theanine, predominantly in combination with caffeine in the form of tea, only one study to date has examined the cognitive effects of this substance alone, and none have examined its effects when combined with caffeine. The present randomised, placebo-controlled, double-blind, balanced crossover study investigated the acute cognitive and mood effects of L-theanine (250 mg), and caffeine (150 mg), in isolation and in combination. Salivary caffeine levels were co-monitored. L-Theanine increased 'headache' ratings and decreased correct serial seven subtractions. Caffeine led to faster digit vigilance reaction time, improved Rapid Visual Information Processing (RVIP) accuracy and attenuated increases in self-reported 'mental fatigue'. In addition to improving RVIP accuracy and 'mental fatigue' ratings, the combination also led to faster simple reaction time, faster numeric working memory reaction time and improved sentence verification accuracy. 'Headache' and 'tired' ratings were reduced and 'alert' ratings increased. There was also a significant positive caffeine x L-theanine interaction on delayed word recognition reaction time. These results suggest that beverages containing L-theanine and caffeine may have a different pharmacological profile to those containing caffeine alone.
Two tyrosine kinases, Src64 and Tec29, regulate the growth of actin rich-ring canals in the Drosophila ovary. We have shown previously that Src64 directs the localization of Tec29 to ring canals, but the mechanism underlying this process was unknown. Here, we show that Tec29 localizes to ring canals via its Src homology 3 (SH3) and Src homology 2 (SH2) domains. Tec29 activity is required for its own ring canal localization, suggesting that a phosphotyrosine ligand for the SH2 domain is generated by Tec29 itself. Src64 regulates this process by phosphorylating Y677 within the kinase domain of Tec29, an event required for Tec29 activation. We also show that the pleckstrin homology (PH) domain of Tec29 has dual functions in mediating Src64 regulation. In the absence of Src64, the PH domain prevents Tec29 ring canal localization. In the presence of Src64, it enhances membrane targeting of Tec29 by a PI(3,4,5)P(3)-mediated mechanism. In the absence of its PH domain, Tec29 constitutively localizes to ring canals, but still requires Src64 for full activation.
77 čajů: pro laiky i labužníky
  • M Thoma
Thoma, M. (2014). 77 čajů: pro laiky i labužníky. Praha: Slovart.