A Randomized Controlled Trial of Brain Endurance Training (BET) to Reduce Fatigue During Endurance Exercise

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RESEARCH POSTER PRESENTATION DESIGN © 2012
www.PosterPresentations.com
•Perception of effort, not muscle fatigue, is the limiting factor
for endurance performance in highly-motivated individuals
(Marcora et al., 2008; Marcora and Staiano, 2010)
•Perception of effort is associated with activity of the
anterior cingulate cortex (ACC) (Williamson et al., 2001;
2002; Staiano et al. unpublished results), not afferent feedback
from the body (Marcora, 2009)
•Damage of the ACC is associated with changes in effort-
based decision-making (rats become “lazy”) (Walton et al.,
2002)
•Mentally fatiguing tasks based on visual stimuli (“video
games”) strongly activate the ACC (Boksem and Tops, 2008)
•The brain adapts to various stimuli and stressors by changing
its structure and function (brain plasticity) (Kolb, 1995)
ABSTRACT HYPOTHESES
PURPOSE: Brain Endurance Training (BET) is a new training method
that uses acute mental fatigue as a training stimulus to induce chronic
reductions in fatigue during physical and/or cognitive tasks. The aim
of this study was to test the efficacy of BET in alleviating fatigue
during endurance exercise in healthy male adults. The hypotheses
were that the combination of BET and standard endurance training
increases endurance exercise performance and reduces rating of
perceived exertion (RPE) more than standard endurance training
alone. METHODS: 35 healthy male volunteers were randomly assigned
to two different training groups: BET and control. Both groups trained
on a cycle ergometer for 60 min at 65% VO2max. Whilst cycling, the BET
group performed a mentally fatiguing task on a computer. The control
group was not involved in any mentally fatiguing task whilst cycling.
Both groups trained three times a week for 12 weeks. VO2max and
endurance exercise performance (time to exhaustion [TTE] test at
75% of current VO2max) were measured at baseline (pre-test), after six
weeks of training (mid-test) and after 12 weeks of training (post-test).
RPE was measured every minute during the TTE test. Data were
analysed using mixed model ANOVAs. RESULTS: VO2max increased
similarly in both groups from 40 ± 5 ml/kg/min to 52 ± 6 ml/kg/min (P
< 0.01). However, TTE increased significantly more in the BET group
(pre-test 28 ± 9 min; mid-test 39 ± 11 min; post-test 55 ± 17 min)
than in the control group (pre-test 18 ± 5 min; mid-test 23 ± 7 min;
post-test 28 ± 12 min) (p< 0.01). Analysis of covariance to adjust for
the pre-test difference in TTE also revealed a larger improvement in
the BET group (+126%) compared to the control group (+42%) (p
<0.01). RPE during the TTE was significantly lower in the BET group
compared to the control group (p< 0.05). CONCLUSION: The results of
this study provide initial evidence that the combination of BET and
standard endurance training is more effective than standard
endurance training alone in alleviating fatigue during endurance
exercise in healthy male adults.
RATIONALE
Changes in relative VO2max induced by BET and traditional physical training
# Significant main effect of test (P < 0.001)
Absolute changes in physical endurance induced by BET and traditional physical training
* Significant group x test interaction (P < 0.001)
PHYSICAL PERFORMANCE RESULTS CONCLUSIONS AND DIRECTIONS
BET seems highly effective in improving endurance performance when
combined with traditional physical training in healthy active males
BET could provide new training stimuli to elite endurance athletes
BET could be used to increase training load in elite endurance athletes
without overloading the musculoskeletal system (injury prevention)
BET could be used in injured athletes that cannot perform physical
training
Beware overtraining (increased load on the brain)
Future studies:
BET in females and elite endurance athletes
Optimisation of BET (volume, intensity, frequency, duration etcetera)
Neurobiological mechanisms underlying positive effects of BET on
perception of effort and endurance performance
REFERENCES
•Boksem, MA. Tops, M.(2008) Mental fatigue: costs and benefits. Brain Res
Rev. Nov;59(1):125-39.
•Kolb, B. (1995). Brain plasticity and behavior. Mahwah, NJ: Erlbaum.
•Marcora, S. M., Bosio, A., & de Morree, H. M. (2008). Locomotor muscle fatigue
increases cardiorespiratory responses and reduces performance during intense
cycling exercise independently from metabolic stress. American Journal of
Physiology.Regulatory, Integrative and Comparative Physiology, 294(3), R874-
83.
•Marcora, S. M., & Staiano, W. (2010). The limit to exercise tolerance in
humans: Mind over muscle? European Journal of Applied Physiology, 109(4),
763-770.
•Marcora, S. (2009). Perception of effort during exercise is independent of
afferent feedback from skeletal muscles, heart, and lungs. Journal of Applied
Physiology (Bethesda, Md.: 1985), 106(6), 2060-2062.
•Walton M, Bannerman D, Rushworth M. (2002). The role of rat medial frontal
cortex in effort-based decision making. J Neurosci, 22: 10996–11003.
•Williamson, J.W., Mccoll, R., Mathews, D., Mitchell, J.H., Raven, P.B., Morgan,
W.P., (2001). Hypnotic Manipulation Of Effort Sense During Dynamic Exercise:
Cardiovascular Responses And Brain Activation. J Appl Physiol, 90, 1392-1399.
ACKNOLEDGMENTS
We would like to thank the BRITISH MINISTRY OF DEFENCE for having
funded the present project .
Systematic repetition of mentally fatiguing tasks:
•increases training load on the brain
•induces adaptations in the ACC or other relevant
cortical areas
•reduces perception of effort
•Increases endurance performance
COGNITIVE AND PERCEPTUAL RESULTS
Dr. Walter Staiano1; Michele Merlini2; Prof. Samuele Marcora2
1. Sport Physiology Department , Team Danmark (Denmark); 2. School of Sport and Exercise Sciences, University of Kent (UK)
A RANDOMIZED CONTROLLED TRIAL OF BRAIN ENDURANCE TRAINING (BET)
TO REDUCE FATIGUE DURING ENDURANCE EXERCISE
Average weekly ratings of mental demand of BET and traditional physical training
¥ Significant main effect of group (P < 0.05)
Relative changes in physical endurance induced by BET and traditional physical training
# Significant main effect of group (P < 0.001)
Average weekly heart rate recorded during BET and traditional physical training
# Significant main effect of week (P < 0.001)
Perception of effort during time to exhaustion at post-test
¥ Significant main effect of group at isotime (P < 0.01)
METHODS
Study Design
Exploratory randomized controlled trial to assess the efficacy of BET + aerobic
exercise against traditional physical training (aerobic exercise only, Control).
Participants were tested at baseline (pre-test), after six weeks of training (mid-
test) and after 12 weeks of training (post-test). We randomly allocated 35 male
subjects to either BET or control.
Training Procedures
•Participants allocated to the BET group cycled at moderate intensity (65%
of VO2max) whilst performing the AX-CPT task we used previously to induce
significant fatigue in healthy subjects
•Participants allocated to the control group cycled at moderate intensity
(65% of VO2max) without performing any concurrent cognitive task
(traditional physical training).
For both groups, the duration of each training session was fixed at 60 min,
with RPE and HR measured throughout. Power output was adjusted in both
groups after mid-test to accommodate for training-induced changes in VO2max.
Participants trained three times a week
-NASA-TLX Scale was used to measure the subjective workload of each of the
36 training sessions.
Testing Procedures
•Visit 1: VO2max Test A standard incremental exercise test (2 min at 50 W +
50 W increments every 2 min) was performed until exhaustion.
•Visit 2: Time to Exhaustion Test After capillary blood analysis, participants
sat on the cycle ergometer and performed a time to exhaustion test
consisting of 3-min warm-up at 40% of peak power output followed by a
rectangular workload corresponding to 75% of VO2max. Pedal frequency was
freely chosen between 60 and 100 RPM and was recorded every minute.
During the incremental exercise and the Time To Exhaustion test oxigen
consumption (breath by breath), heart rate (continuously), RPE (every
minute), mood and motivation (at the beginning of every test) were
measured.