SEATTLE, WA—Chewing caffeine gum for five minutes immediately upon awakening may counter sleep inertia, especially for reaction time, according to a data presented at SLEEP 2015.
However, “results were mixed on driving measures, suggesting caffeine gum may not be as useful for improving road safety,” noted Rachel Markwald, PhD, of the Naval Health Research Center, Warfighter Performance Department, San Diego, CA. “This may have implications for populations such as emergency responders and with military operational readiness. More research will be needed to determine if effects generalize to other tasks,” he added.
Previously, Dr. Markwald and colleagues found caffeine gum had shown potential as a countermeasure for impairments during sleep inertia, as assessed by the psychomotor vigilance task and a simulated drive. For SLEEP 2015, the full data set were examined “to determine the effectiveness of caffeine gum during sleep inertia.”
A total of 22 healthy adults, 19 of whom were active-duty service members, completed three days of consistent sleep schedules before being admitted to the laboratory for two overnight visits separated by ≥5 days. Mean age of the participants was 29.99±7.3 years and mean BMI was 25.7±2.0kg/m2.
In the double-blind, counterbalanced study, 200mg caffeine or placebo gum was administered to the participants immediately upon awakening from a scheduled two-hour episode of sleep.
After five minutes of chewing, the gum was discarded, followed by a 10-minute psychomotor vigilance task and a 10-minute simulated drive, the latter of which included a divided attention task. Dr. Markwald and researchers assessed subjective sleepiness via the Karolinska Sleepiness Scale (KSS).
Results showed that compared with placebo, caffeine gum significantly improved median reaction time, mean reaction time, the slowest 10% time, and the number of lapses in psychomotor vigilance task outcomes (all P<0.05).
“For all psychomotor vigilance task outcomes except median reaction time, this improvement occurred during the first half of the psychomotor vigilance task,” she reported.
Caffeine gum significantly decreased both divided attention mean reaction time and speed variability during the 10-minute simulated drive (both P<0.05).