How does fatigue affect reaction time

A total of 45 Czech male MMA athletes took part in the study. When compared with previous studies investigating the physical profile of MMA fighters and similar combat sports athletes [ 4 , 40 — 43 ], our sample does not differ in reported descriptive parameters, e. All participants were informed about the study goals, approved their participation by providing written informed consent, and were reimbursed with CZK app.

We used a within-subject experimental design to test the effect of induced acute fatigue on RT, MT and their consistency. After familiarization with the data collection procedures, participants performed the first—a baseline PRE condition —RT test. To induce fatigue, participants completed a seconds supramaximal anaerobic arm-cranking exercise at maximal speed against a frictional resistance by Wingate test which was immediately followed by the second RT test POST condition Fig 1.

During the RT S1, participants begin with the index finger of their dominant hand resting on a touch-sensitive rest button located on the VTS-6 response panel. At the onset of a stimulus, the participant lifts the index finger from rest button RT and move the finger as quickly as possible to a reaction button MT which is located above the rest button.

The finger must then be returned to the rest button and must remain on the rest button until the subsequent stimulus. This procedure continues for the duration of the test, which consists of 28 visual stimuli, each of which appears on the screen maximally for 1 second in which the participant is supposed to respond. The length of pause between each stimulus varies between 2.

Depending on the speed of each participant, the test lasted on average 4 to 5 minutes. Before the baseline test PRE condition , participants completed a familiarisation run in which they learned how to perform the task and responded correctly to an abbreviated practice version of the test. If needed, feedback was given to help participants understand and complete the practice test correctly.

After performing the familiarisation trial and confirming that they understood the test, the actual PRE test began. The POST condition test did not include any re-familiarisation.

More specifically, they include the mean reaction time RT; the time between the onset of the visual stimulus and the initial moment lifting of the finger from the rest button , the mean movement time MT; the time between the finger leaving the rest button and touching the reaction button , and the variance in RT and MT times as a measure of performance consistency.

For descriptive statistics, see Table 1. Further, raw RT and MT values were recorded for each stimulus, together with the number of correct responses lifting a finger from the rest button and touching the response button , the number of incomplete responses lifting a finger from the rest button but not touching the response button , and the number of failed responses not lifting the finger from rest button.

In the subsequent analysis, we used the individual raw RT, and MT and variance values recorded for each of 28 stimuli.

An upper-body Wingate test was used to induce acute neuromuscular fatigue via a Monark arm ergometer model Rump-Rokos 4. While seated on a bench, participants warmed up by cranking against no resistance until the heart rate reached beats per minute. After that, participants started to crank as quickly as possible until they reached revolutions per minute, which was followed by activation of the load and participants were verbally encouraged to perform at maximal turning rates throughout the second period.

Several variables can be measured as outcomes of the Wingate test like peak anaerobic power output or total work performed, among others.

Here, to assess a relative decrease in performance fatigue , we focused only on the percentage of power decrease during the test Fatigue index in further analyses. All statistical tests were performed using jamovi 1. After an initial data exploration of the PRE RT values of all 28 stimuli, we found that the RT of the first four stimuli showed higher means and SD compared to the rest of subsequent stimuli, despite previously performed familiarisation trial for details, see the Supplementary materials.

Therefore, we excluded these first four stimuli from all subsequent analysis, leaving data from the remaining 24 stimuli. This approach resulted in a total of individual responses 45 participants reacted to 24 stimuli at 2 time points. Thus the final sample consisted of individual responses. We used this analytical approach to account for variation in the level of the individual participants and to avoid potential bias due to the data aggregation i.

Further, using R R x64 3. The proportions of reduced error pseudo R 2 are reported as R 2 Marginal R 2 M , the variance explained by the fixed effects over the total variance of the dependent variable and R 2 Conditional R 2 C , the variance explained by the fixed and the random effects together over the total variance of the dependent variable. There was no significant effect of fatigue index and the Condition:Stimulus interaction.

Fixed effect parameters estimates for the RT model are reported in Table 2. Other covariates fatigue index, Stimulus and Condition:Stimulus interaction in this model were not significant. Fixed effect parameters estimates for RT residuals model are reported in Table 2. The results thus show that mean MT remained uninfluenced by the fatiguing task. Fixed effect parameters estimates for the MT model are reported in Table 3.

Further, the Stimulus and interaction between Condition:Stimulus were also not statistically significant. Fixed effect parameters estimates for MT residuals model are reported in Table 3.

In the present study, we tested the effect of induced acute fatigue on simple visual reaction time measures. For this purpose, we measured RT, MT and their consistency in a sample of male MMA fighters before and after they performed an upper-body Wingate test.

Overall, we found that mean RT were significantly higher and less consistent participants sometimes reacted slower and other times faster in the POST compared to the PRE condition, no such changes were observed in mean MT and MT consistency. Further, the fatigue index during the Wingate test did not influence RT or their consistency, but a greater fatigue index was associated with slower MT in POST condition.

These results thus suggest that acute fatigue affects overall performance and the consistency of simple RT measures in MMA fighters. Several previous investigations showed similar significant effects of fatigue on overall response performance.

With increasing exercise intensity, the reaction times become slower [ 30 , 36 , 52 ] as well as in case of near-maximal or super-maximal performance [ 19 , 25 , 35 , 37 ]. In the current study, athletes performed standardized supramaximal arm-cranking exercise, and our results on both RT and MT are consistent with the line of research showing the negative effect of near-maximal effort and fatigue on performance in reaction time tasks.

Interestingly, the majority of previous studies does not clearly distinguish between overall response performance and its components—RT and MT. Changes in both RT and MT in response to accumulated fatigue are thus not frequently described, or only overall performance or RT is reported [for an exception see 36 ]. Interestingly, we found a close to significance positive effect of Stimulus number on RT. Participants tend to react faster with every stimulus, and as we found no interaction between Condition and Stimulus in the RT model, this pattern was consistent regardless of fatigue.

Our study thus bring new evidence of a negative influence of acute fatigue on RT and MT performance consistency. MMA fights involve explosive and dynamic-strength work combining short periods of activity and rest.

We thus employed short exercise consisting of 30 seconds of supramaximal work to assess the possible effect in a simple experimental setting. However, using only one such period might not represent sufficient load to elicit adequate fatigue comparable to the one experienced during the actual fight as active periods are repeated numerously during the whole fight. Studies by Gierczuk et al. Future studies thus should use multiple repetitions of fatiguing tasks—or conditions in general similar to the actual competition—to better describe patterns in reaction times measures changes due to cumulative fatigue.

Nevertheless, our results indicate that even relatively short exercise periods affect reaction times measures and their consistency. It remains an open question for further investigation, whether more accumulated fatigue would entail greater changes [ 19 , 35 ]. In our study, we selected the arm-cranked Wingate test to induce fatigue. Arm-cranking exercise can be viewed as movements analogous to typical arm movements that are associated with combat sports relying on striking. Changes in performance due to induced fatigue through exercise can be explained by arousal theory [ 54 ] and multidimensional allocation of resources theory [ 55 ].

The amount of mental effort that individuals invest in a task and an increase in arousal accompanying physical exercise are factors determining resulting performance.

At low and moderate arousal levels, the extra invested mental effort can compensate for performance losses and performance increases towards an optimal point. At very high arousal levels, performance is expected to decrease when the limited capacity for the effort is exceeded.

The arousal encountered in the current study elicited by the Wingate test appeared sufficient and severe enough to affect mean RT and RT performance consistency.

Such arousal thus influences overall performance including RT measurements based on movements of a finger. Further, the Vienna system simple visual reaction times RT S-1 test selected for this study might not seem like the most suitable measure due to MMA complexity or in comparison with other methods used to assess response performance in previous investigations e.

MMA fight techniques consist of consecutively performed complex actions series of holds, clinches, takedown attempts, and strike exchanges which may call for more complex and selective reactions and decision making.

In practice, fighters often perform quick single movements lasting fractions of seconds knockout attempts, swipes and they need to react swiftly in response to fast limb or trunk movements of an opponent. Usually, simple reactions are involved in response to such stimulus, and a well-trained contra-movement is applied. Hence simple reactions can be considered as the first level of automatic response preceding further and more complex processing of adequate reactions and in turn successful performance.

We might observe such a pattern in many martial arts, and combat sport fights where matches are resolved in split-second inattentiveness or due to slower than desirable response. To conclude, a short period of induced fatigue negatively affects performance in a simple visual reaction times task in a sample of MMA fighters. Successful performance in sports is affected by many physical and psychological factors such as strength, endurance, strategic thinking, or coping with stress.

After a high-intensity effort, physical and mental fatigue may appear, and both may affect performance including ability to react quickly. This ability is probably highly important for combat sports athletes, where slower-than-desired reactions decrease chances to respond adequately and succeed in a match. Majority of studies usually investigate only the effect of averaged reaction times. Here we show evidence that not only mean reactions, but other reaction times measures are affected by fatigue differently.

RT are negatively influenced by fatigue though marginally in the case , more importantly RT consistency is lower, and fatigue index has negative effect on MT. Typically, the majority of attention is devoted to physical training including aerobic and anaerobic performance especially in combat sports such as MMA due to its dynamic and physically demanding nature.

However, our results suggest that in such sports, where split-second errors cannot be afforded, the reaction times consistency might be more important criteria than previously considered. This could lead to development of specialized training programs focused on improving fight strategy under fatiguing conditions. During the RT S1, participants begin with the index finger of their dominant hand resting on a touch-sensitive rest button located on the VTS-6 response panel.

At the onset of a stimulus, the participant lifts the index finger from rest button RT and move the finger as quickly as possible to a reaction button MT which is located above the rest button. The finger must then be returned to the rest button and must remain on the rest button until the subsequent stimulus.

This procedure continues for the duration of the test, which consists of 28 visual stimuli, each of which appears on the screen maximally for 1 second in which the participant is supposed to respond. The length of pause between each stimulus varies between 2.

Depending on the speed of each participant, the test lasted on average 4 to 5 minutes. Before the baseline test PRE condition , participants completed a familiarisation run in which they learned how to perform the task and responded correctly to an abbreviated practice version of the test.

If needed, feedback was given to help participants understand and complete the practice test correctly. After performing the familiarisation trial and confirming that they understood the test, the actual PRE test began. The POST condition test did not include any re-familiarisation. More specifically, they include the mean reaction time RT; the time between the onset of the visual stimulus and the initial moment lifting of the finger from the rest button , the mean movement time MT; the time between the finger leaving the rest button and touching the reaction button , and the variance in RT and MT times as a measure of performance consistency.

For descriptive statistics, see Table 1. Further, raw RT and MT values were recorded for each stimulus, together with the number of correct responses lifting a finger from the rest button and touching the response button , the number of incomplete responses lifting a finger from the rest button but not touching the response button , and the number of failed responses not lifting the finger from rest button.

In the subsequent analysis, we used the individual raw RT, and MT and variance values recorded for each of 28 stimuli. An upper-body Wingate test was used to induce acute neuromuscular fatigue via a Monark arm ergometer model Rump-Rokos 4.

While seated on a bench, participants warmed up by cranking against no resistance until the heart rate reached beats per minute. After that, participants started to crank as quickly as possible until they reached revolutions per minute, which was followed by activation of the load and participants were verbally encouraged to perform at maximal turning rates throughout the second period. Several variables can be measured as outcomes of the Wingate test like peak anaerobic power output or total work performed, among others.

Here, to assess a relative decrease in performance fatigue , we focused only on the percentage of power decrease during the test Fatigue index in further analyses. All statistical tests were performed using jamovi 1. After an initial data exploration of the PRE RT values of all 28 stimuli, we found that the RT of the first four stimuli showed higher means and SD compared to the rest of subsequent stimuli, despite previously performed familiarisation trial for details, see the Supplementary materials.

Therefore, we excluded these first four stimuli from all subsequent analysis, leaving data from the remaining 24 stimuli. This approach resulted in a total of individual responses 45 participants reacted to 24 stimuli at 2 time points. Thus the final sample consisted of individual responses.

We used this analytical approach to account for variation in the level of the individual participants and to avoid potential bias due to the data aggregation i. Further, using R R x64 3. The proportions of reduced error pseudo R 2 are reported as R 2 Marginal R 2 M , the variance explained by the fixed effects over the total variance of the dependent variable and R 2 Conditional R 2 C , the variance explained by the fixed and the random effects together over the total variance of the dependent variable.

There was no significant effect of fatigue index and the Condition:Stimulus interaction. Fixed effect parameters estimates for the RT model are reported in Table 2.

Other covariates fatigue index, Stimulus and Condition:Stimulus interaction in this model were not significant. Fixed effect parameters estimates for RT residuals model are reported in Table 2. The results thus show that mean MT remained uninfluenced by the fatiguing task. Fixed effect parameters estimates for the MT model are reported in Table 3. Further, the Stimulus and interaction between Condition:Stimulus were also not statistically significant.

Fixed effect parameters estimates for MT residuals model are reported in Table 3. In the present study, we tested the effect of induced acute fatigue on simple visual reaction time measures. For this purpose, we measured RT, MT and their consistency in a sample of male MMA fighters before and after they performed an upper-body Wingate test. Overall, we found that mean RT were significantly higher and less consistent participants sometimes reacted slower and other times faster in the POST compared to the PRE condition, no such changes were observed in mean MT and MT consistency.

Further, the fatigue index during the Wingate test did not influence RT or their consistency, but a greater fatigue index was associated with slower MT in POST condition. These results thus suggest that acute fatigue affects overall performance and the consistency of simple RT measures in MMA fighters. Several previous investigations showed similar significant effects of fatigue on overall response performance.

With increasing exercise intensity, the reaction times become slower [ 30 , 36 , 52 ] as well as in case of near-maximal or super-maximal performance [ 19 , 25 , 35 , 37 ]. In the current study, athletes performed standardized supramaximal arm-cranking exercise, and our results on both RT and MT are consistent with the line of research showing the negative effect of near-maximal effort and fatigue on performance in reaction time tasks.

Interestingly, the majority of previous studies does not clearly distinguish between overall response performance and its components—RT and MT. Changes in both RT and MT in response to accumulated fatigue are thus not frequently described, or only overall performance or RT is reported [for an exception see 36 ]. Interestingly, we found a close to significance positive effect of Stimulus number on RT. Participants tend to react faster with every stimulus, and as we found no interaction between Condition and Stimulus in the RT model, this pattern was consistent regardless of fatigue.

Our study thus bring new evidence of a negative influence of acute fatigue on RT and MT performance consistency. MMA fights involve explosive and dynamic-strength work combining short periods of activity and rest. We thus employed short exercise consisting of 30 seconds of supramaximal work to assess the possible effect in a simple experimental setting.

However, using only one such period might not represent sufficient load to elicit adequate fatigue comparable to the one experienced during the actual fight as active periods are repeated numerously during the whole fight.

Studies by Gierczuk et al. Future studies thus should use multiple repetitions of fatiguing tasks—or conditions in general similar to the actual competition—to better describe patterns in reaction times measures changes due to cumulative fatigue. Nevertheless, our results indicate that even relatively short exercise periods affect reaction times measures and their consistency.

It remains an open question for further investigation, whether more accumulated fatigue would entail greater changes [ 19 , 35 ]. In our study, we selected the arm-cranked Wingate test to induce fatigue.

Arm-cranking exercise can be viewed as movements analogous to typical arm movements that are associated with combat sports relying on striking. Changes in performance due to induced fatigue through exercise can be explained by arousal theory [ 54 ] and multidimensional allocation of resources theory [ 55 ]. The amount of mental effort that individuals invest in a task and an increase in arousal accompanying physical exercise are factors determining resulting performance.

At low and moderate arousal levels, the extra invested mental effort can compensate for performance losses and performance increases towards an optimal point. At very high arousal levels, performance is expected to decrease when the limited capacity for the effort is exceeded. The arousal encountered in the current study elicited by the Wingate test appeared sufficient and severe enough to affect mean RT and RT performance consistency.

Such arousal thus influences overall performance including RT measurements based on movements of a finger.

Further, the Vienna system simple visual reaction times RT S-1 test selected for this study might not seem like the most suitable measure due to MMA complexity or in comparison with other methods used to assess response performance in previous investigations e.

MMA fight techniques consist of consecutively performed complex actions series of holds, clinches, takedown attempts, and strike exchanges which may call for more complex and selective reactions and decision making. In practice, fighters often perform quick single movements lasting fractions of seconds knockout attempts, swipes and they need to react swiftly in response to fast limb or trunk movements of an opponent.

Usually, simple reactions are involved in response to such stimulus, and a well-trained contra-movement is applied. Hence simple reactions can be considered as the first level of automatic response preceding further and more complex processing of adequate reactions and in turn successful performance.

We might observe such a pattern in many martial arts, and combat sport fights where matches are resolved in split-second inattentiveness or due to slower than desirable response. To conclude, a short period of induced fatigue negatively affects performance in a simple visual reaction times task in a sample of MMA fighters. Successful performance in sports is affected by many physical and psychological factors such as strength, endurance, strategic thinking, or coping with stress. After a high-intensity effort, physical and mental fatigue may appear, and both may affect performance including ability to react quickly.

This ability is probably highly important for combat sports athletes, where slower-than-desired reactions decrease chances to respond adequately and succeed in a match. Majority of studies usually investigate only the effect of averaged reaction times. Here we show evidence that not only mean reactions, but other reaction times measures are affected by fatigue differently. RT are negatively influenced by fatigue though marginally in the case , more importantly RT consistency is lower, and fatigue index has negative effect on MT.

Typically, the majority of attention is devoted to physical training including aerobic and anaerobic performance especially in combat sports such as MMA due to its dynamic and physically demanding nature.

However, our results suggest that in such sports, where split-second errors cannot be afforded, the reaction times consistency might be more important criteria than previously considered. This could lead to development of specialized training programs focused on improving fight strategy under fatiguing conditions.

National Center for Biotechnology Information , U. PLoS One. Published online Jan James J. Yi-Hung Liao, Editor. Author information Article notes Copyright and License information Disclaimer. Received Aug 12; Accepted Dec This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

S1 File: Reaction times exploration. There are several hypotheses that attempt to explain the reason for increased reaction times after sleep deprivation. These competing drives interfere with our attention from moment to moment, leading to cognitive impairment and an increased reaction time.

Reaction times are important in a multitude of professions and activities. Increased reaction times can affect the performance of athletes, as well as the safety and productivity of shift workers, medical professionals, students, pilots, and anyone else whose work requires sustained attention and quick reflexes.

Increased reaction times are particularly dangerous when a person gets behind the wheel of a car. The National Highway Traffic Safety Administration estimates that up to 6, fatal crashes each year may be due to drowsy drivers. Driving while underslept can make it more difficult to react quickly to changing road conditions and has been linked to dangerous practices like lane drifting. There are several ways to test your reaction time at home. This simple reaction time test allows you to see how long it takes you to catch a falling ruler.

To start, have a friend hold a ruler on the highest measurement. Place your open thumb and forefinger slightly below the ruler, ready to catch it when the ruler falls. Then, have your friend drop the ruler while you catch it between your thumb and forefinger as quickly as possible.

Record the measurement where you caught the ruler. The lower the number, the quicker the ruler was caught and the higher your reaction time. For fun, switch positions with your friend and let them try, then compare your results. You can also compare your reaction time during different conditions, like with or without background noise.

The psychomotor vigilance test PVT measures how long it takes to respond to a visual stimulus. Images are shown on an otherwise blank screen at random times and participants are asked to touch a button when they see the image. While this test can be difficult to recreate on your own, there are several computer and smartphone-based applications that allow you to test your reaction time under different conditions.

Many people want to improve their reaction times to be a safer driver, more productive at work, or quicker at responding in conversations. Others, like new parents, shift workers, and emergency responders, need to maintain quick reaction times under conditions that often require them to miss sleep. Improving your sleep hygiene is a great first step to feeling more rested and improving your reaction time.

Sleep hygiene means incorporating practices that promote better sleep, while reducing practices that are making sleep more challenging. Here are a few tips for improving your sleep hygiene. Rob writes about the intersection of sleep and mental health and previously worked at the National Cancer Institute. His research and clinical practice focuses on the entire myriad of sleep disorders.

Insomnia is a common sleep disorder characterized by a persistent difficulty to fall or remain asleep despite the opportunity to…. Sleep problems can affect anyone, but women are more likely to experience insomnia than men.

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It is mandatory to procure user consent prior to running these cookies on your website. The Sleep Foundation editorial team is dedicated to providing content that meets the highest standards for accuracy and objectivity. Our editors and medical experts rigorously evaluate every article and guide to ensure the information is factual, up-to-date, and free of bias. Updated December 11, Written by Rob Newsom. Medically Reviewed by Dr.