28779
document
The effects of chewing versus caffeine on alertness , cognitive performance and cardiac autonomic activity during sleep deprivation . Chewing has been shown to alleviate feelings of sleepiness and improve cognitive performance during the day . This study investigated the effect of chewing on alertness and cognitive performance across one night without sleep as well as the possible mediating role of cardiac autonomic activity . Fourteen adults participated in a randomized , counterbalanced protocol employing a chewing , placebo and caffeine condition . Participants completed tasks assessing psychomotor vigilance , tracking , grammatical reasoning , alertness and sleepiness each hour across the night . All participants received either placebo or caffeine ( 200 mg ) , while the chewing condition also chewed on a tasteless and odorless substance for 15 min each hour . Heart rate ( HR ) , root mean square of the successive differences in R-R intervals on the ECG ( RMSSD ) , and preejection period ( PEP ) were simultaneously recorded . Alertness and cognitive performance amongst the chewing condition did not differ or were in fact worse when compared with placebo . Similarly , measures of HR and RMSSD remained the same between these two conditions ; however , PEP was reduced in the later part of the night in the chewing condition compared with a relative increase for placebo . Caffeine led to improved speed and accuracy on cognitive tasks and increased alertness when compared with chewing . Relative increases in RMSSD and reductions in HR were demonstrated following caffeine ; however , no change in PEP was seen . Strong associations between cardiac parasympathetic activity and complex cognitive tasks , as well as between subjective alertness and simpler cognitive tasks , suggest a differential process mediating complex versus simple cognitive performance during sleep deprivation .
28780
Intervention_Physical
chewing
28781
Intervention_Pharmacological
caffeine
28782
Intervention_Physical
Chewing
28783
Intervention_Pharmacological
chewing
28784
Intervention_Other
chewing
28785
Intervention_Control
placebo
28786
Intervention_Pharmacological
caffeine
28787
Intervention_Control
placebo
28788
Intervention_Pharmacological
caffeine
28789
Intervention_Other
chewing
28790
Intervention_Other
chewed on a tasteless and odorless substance
28791
Intervention_Physical
chewing
28792
Intervention_Pharmacological
Caffeine
28793
Intervention_Physical
chewing
28794
Outcome_Other
effects
28795
Outcome_Other
effect
28796
Outcome_Mental
psychomotor vigilance
28797
Outcome_Mental
tracking
28798
Outcome_Mental
grammatical reasoning
28799
Outcome_Mental
alertness
28800
Outcome_Mental
sleepiness
28801
Outcome_Physical
Heart rate ( HR )
28802
Outcome_Physical
root mean square of the successive differences in R-R intervals on the ECG ( RMSSD )
28803
Outcome_Physical
preejection period ( PEP )
28804
Outcome_Mental
Alertness and cognitive performance
28805
Outcome_Physical
HR
28806
Outcome_Physical
RMSSD
28807
Outcome_Physical
PEP
28808
Outcome_Other
improved speed
28809
Outcome_Physical
and
28810
Outcome_Other
accuracy on cognitive tasks
28811
Outcome_Physical
and
28812
Outcome_Other
increased alertness
28813
Outcome_Physical
Relative increases in RMSSD
28814
Outcome_Physical
reductions in HR
28815
Outcome_Physical
no change in PEP
28816
Outcome_Mental
alertness
28817
Outcome_Mental
simpler cognitive tasks