Use of subjectively reported parameters of physical and mental fatigue, sleep and stress for assessment of ultra-endurance cycling induced cognitive impairment (Veloreality)

INTRODUCTION: Objectively determined physical and mental fatigue has detrimental effects on cognition. However, sub-
jective perception of fatigue can vary significantly from person to person. The aim of this study was to determine an extent
to which subjectively reported parameters (SRPs) of physical and mental fatigue can be used to assess cognitive perfor-
mance.
METHODS: 39 male and 4 female amateur cyclists (38.8±8.7 y/o, BMI: 25.2±2.8 kg/m2) who completed an ultra-
endurance cycling race in under 24-hours completed cognitive function test battery (Stroop test (ST), Finger tapping test
(FTT)) pre-race, post-race and ~20h in the recovery period. Additionally, following SRPs were evaluated: sleep hours, sleep
quality, mental fatigue, physical fatigue, physical strength, stress levels during the previous day, effort to answer the ques-
tions in a scale from 1 to 10. Changes between the timepoints were assessed by one-way repeated measures ANOVA or
Friedman test. The association between cognitive function test variables that changed significantly and SRPs was analysed
using mixed model regressions.
RESULTS: Significant change in all SRPs except for stress levels during the previous day was observed from pre- to post-
race (p<.001). While in recovery sleep quality, mental fatigue and effort to answer the questions had returned to pre-race
levels, there was a significant increase in sleep hours, physical fatigue and reduced physical strength reported. The in-
crease in muscle pain in post-race (from 2 (1;2) to 5 (4;8) was sustained in recovery (5 (3;7), p<.001).
The post-race ST average time for correct reaction of all 3 stages increased: by 22, 35 and 68 ms (p<.001), corresponding-
ly. Stage 1 and 3 values returned to baseline in recovery, yet stage 2 showed an improvement compared to baseline (from
651 (88) to 630 (89) ms, p<.001). Performance in ST stage 2 was associated with a better sleep quality, reducing the aver-
age time for correct reactions by 10.10 ms (p<.001) for a point increase. In stage 3, average time for correct reactions was
increased by stress levels during the previous day by 12.80 ms (p=.015) and decreased physical strength by 12.70 ms
(p=0.006) per point.
FTT showed impaired performance of the non-dominant hand in post-race; average number of taps decreased from 54.7
(6.4) to 52.0 (6.9), p<.001, average interval between taps increased from 189.0 (22.5) to 202.0 (27.1) ms, p<.001 and re-
turned to baseline in recovery. Higher effort to answer questions was associated with a diminished performance in the FTT
for non-dominant hand (p=0.028).
CONCLUSION: A single SRP cannot estimate the changes in cognition, but perceived effort to answer the questions is
associated with fine motor performance measured by FTT, and sleep quality, stress levels and physical strength are asso-
ciated with executive functions measured by ST.