Pan African Clinical Trials Registry
South African Medical Research Council, South African Cochrane Centre
PO Box 19070, Tygerberg, 7505, South Africa
Telephone: +27 21 938 0835 or +27 21 938 0967
Email: pactradmin@mrc.ac.za Website: pactr.samrc.ac.za
Trial no.: PACTR202609482175725 Date of Registration: 10/09/2026
Trial Status: Retrospective registration - This trial was registered after enrolment of the first participant
TRIAL DESCRIPTION
Public title Caffeinated chewing gum as a countermeasure to post-nap sleep inertia after a 90-min afternoon nap opportunity in physically active young men: a randomized four-condition crossover study.
Official scientific title Caffeinated chewing gum as a countermeasure to post-nap sleep inertia after a 90-min afternoon nap opportunity in physically active young men: a randomized four-condition crossover study.
Brief summary describing the background and objectives of the trial Background: Long naps can be followed by sleep inertia, a transient post-awakening state characterized by reduced arousal, increased sleepiness, and impaired neurobehavioral performance. Caffeinated chewing gum delivers caffeine rapidly; however, its post-nap effects remain unclear. Objective: To determine whether 300 mg of caffeinated gum attenuates post-nap sleepiness and impairments in readiness, vigilance, and physical performance after a 90-min afternoon nap opportunity in physically active young men.
Type of trial RCT
Acronym (If the trial has an acronym then please provide)
Disease(s) or condition(s) being studied Sleep inertia
Sub-Disease(s) or condition(s) being studied
Purpose of the trial Physical activity and nutrition
Anticipated trial start date 01/06/2026
Actual trial start date 01/06/2026
Anticipated date of last follow up 27/06/2026
Actual Last follow-up date
Anticipated target sample size (number of participants) 18
Actual target sample size (number of participants)
Recruitment status Completed
Publication URL
Secondary Ids Issuing authority/Trial register
STUDY DESIGN
Intervention assignment Allocation to intervention If randomised, describe how the allocation sequence was generated Describe how the allocation sequence/code was concealed from the person allocating the participants to the intervention arms Masking If masking / blinding was used
Crossover: all participants receive all interventions in different sequence during study Randomised Simple randomization using a randomization table created by a computer software program Allocation Sequence/Code was not concealed Open-label(Masking Not Used)
INTERVENTIONS
Intervention type Intervention name Dose Duration Intervention description Group size Nature of control
Control Group No Nap Caffeine-free, 0% carbohydrate placebo gum Approximately 2 hours 50 minutes (from 13:20 to 16:10) Participants arrived at the laboratory at 13:20. From 13:30 to 15:00, participants remained awake for 90 min in a quiet room engaged in sedentary reading. At 15 min after the end of the rest period (time 0), they chewed placebo gum continuously for 15 min. The gum was discarded at 30 min, immediately before the first assessment block. The first assessment block began 30 min after the end of rest and included: Stanford Sleepiness Scale (SSS), readiness-to-perform rating, 5-min Psychomotor Vigilance Task (PVT), standardized 5-min warm-up, handgrip strength (HGS), and countermovement jump (CMJ). The second assessment block followed the same sequence at 60 min. 18 Placebo
Control Group No Nap and Caffeine 300 mg caffeine (three 100-mg pieces of Kick-start caffeinated gum), equivalent to approximately 4.1 mg·kg⁻¹ Approximately 2 hours 50 minutes (from 13:20 to approximately 16:10) Participants arrived at the laboratory at 13:20. From 13:30 to 15:00, participants remained awake for 90 min in a quiet room engaged in sedentary reading. At 15 min after the end of the rest period (time 0), they chewed 300 mg caffeinated gum continuously for 15 min. The gum was discarded at 30 min, immediately before the first assessment block. The first assessment block began 30 min after the end of rest and included: Stanford Sleepiness Scale (SSS), readiness-to-perform rating, 5-min Psychomotor Vigilance Task (PVT), standardized 5-min warm-up, handgrip strength (HGS), and countermovement jump (CMJ). The second assessment block followed the same sequence at 60 min. No additional gum was administered before the 60-min assessment. 18 Active-Treatment of Control Group
Experimental Group Nap Caffeine-free, 0% carbohydrate placebo gum (matched for flavor and appearance) Approximately 2 hours 50 minutes (from 13:20 to approximately 16:10) Participants arrived at the laboratory at approximately 13:20. From 13:30 to 15:00, participants were provided a maximum 90-minute nap opportunity in a quiet, darkened room maintained at an ambient temperature of 22 ± 1 °C. Post-awakening timing was anchored to operational awakening (spontaneous awakening via a manual signaling device or gentle awakening by the investigator at 90 minutes). For the first 15 minutes after operational awakening, participants remained seated quietly without physical activity. At 15 minutes, they chewed the placebo gum continuously for 15 minutes. The gum was discarded at 30 minutes, immediately before the first assessment block. The first assessment block began 30 minutes after awakening and followed a fixed sequence: (1) Stanford Sleepiness Scale (SSS), (2) readiness-to-perform rating, (3) 5-minute Psychomotor Vigilance Task (PVT), (4) standardized 5-minute warm-up, (5) handgrip strength (HGS), and (6) countermovement jump (CMJ). The second assessment block followed the exact same sequence at 60 minutes after awakening. Nap duration and nocturnal sleep were monitored using a wrist-worn Fitbit Charge 6. No additional gum was administered before the 60-minute assessment. 18
Experimental Group Nap and Caffeine 300 mg caffeine (three 100-mg pieces of Kick-start caffeinated chewing gum), equivalent to approximately 4.1 mg·kg⁻¹ Approximately 2 hours 50 minutes (from 13:20 to approximately 16:10) Participants arrived at the laboratory at approximately 13:20. From 13:30 to 15:00, participants were provided a maximum 90-minute nap opportunity in a quiet, darkened room maintained at an ambient temperature of 22 ± 1 °C. Post-awakening timing was anchored to operational awakening (spontaneous awakening via a manual signaling device or gentle awakening by the investigator at 90 minutes). For the first 15 minutes after operational awakening, participants remained seated quietly without physical activity. At 15 minutes, they chewed 300 mg of caffeinated gum continuously for 15 minutes. The gum was discarded at 30 minutes, immediately before the first assessment block. The first assessment block began 30 minutes after awakening and followed a fixed sequence: (1) Stanford Sleepiness Scale (SSS), (2) readiness-to-perform rating, (3) 5-minute Psychomotor Vigilance Task (PVT), (4) standardized 5-minute warm-up, (5) handgrip strength (HGS), and (6) countermovement jump (CMJ). The second assessment block followed the exact same sequence at 60 minutes after awakening. No additional gum was administered before the 60-minute assessment. 18
ELIGIBILITY CRITERIA
List inclusion criteria List exclusion criteria Age Category Minimum age Maximum age Gender
Healthy young male physical-education students. Habitual daytime nappers (at least one spontaneous nap per week). Habitual caffeine consumers (100–400 mg/day). Able to complete all experimental procedures. Diagnosed sleep disorders. Regular night-shift work or transmeridian travel within the past month. Neurological, cardiovascular, or metabolic disorders. Musculoskeletal conditions limiting maximal physical testing. Current use of medications or supplements that could affect sleep, alertness, or cognitive performance. Extreme morning or evening chronotypes (based on MEQ). Adult: 18 Year(s)-44 Year(s) 20 Year(s) 23 Year(s) Male
ETHICS APPROVAL
Has the study received appropriate ethics committee approval Date the study will be submitted for approval Date of approval Name of the ethics committee
Yes 24/03/2026 CERS ISSEPS
Ethics Committee Address
Street address City Postal code Country
BP 1068 Sfax 3000 Tunisia
OUTCOMES
Type of outcome Outcome Timepoint(s) at which outcome measured
Primary Outcome Cognitive performance / Psychomotor vigilance, assessed using the 5-minute Psychomotor Vigilance Task (PVT), including mean reaction time (ms) and number of lapses. Physical performance, assessed by maximal handgrip strength (HGS) in kg and countermovement jump (CMJ) height in cm. 30 minutes and 60 minutes post-awakening / end of rest.
Secondary Outcome Subjective sleepiness, assessed using the Stanford Sleepiness Scale (SSS). Readiness to perform, assessed using a 0–10 numerical rating scale. 30 minutes and 60 minutes post-awakening / end of rest.
RECRUITMENT CENTRES
Name of recruitment centre Street address City Postal code Country
Laboratoire EM2S BP 1068 Sfax 3000 Tunisia
FUNDING SOURCES
Name of source Street address City Postal code Country
Ali Abdelkafi 3064 Sfax 3064 Tunisia
SPONSORS
Sponsor level Name Street address City Postal code Country Nature of sponsor
Primary Sponsor Ali Abdelkafi Cite Bahri 2 Rue 2007 N03 Sfax 3064 Tunisia Individual
COLLABORATORS
Name Street address City Postal code Country
Hamdi Chtourou BP 1068 Sfax 3000 Tunisia
Khaled Trabelsi BP 1068 Sfax 3000 Tunisia
CONTACT PEOPLE
Role Name Email Phone Street address
Principal Investigator Ali Abdelkafi ali.abdelkafi@isseps.usf.tn +21620228271 Cite Bahri 2 Rue 2007 N03
City Postal code Country Position/Affiliation
Sfax 3064 Tunisia PhD Student
Role Name Email Phone Street address
Public Enquiries Ali Abdelkafi ali.abdelkafi@isseps.usf.tn +21620228271 Cite Bahri 2 Rue 2007 N03
City Postal code Country Position/Affiliation
Sfax 3064 Tunisia PhD Student
Role Name Email Phone Street address
Scientific Enquiries Ali Abdelkafi ali.abdelkafi@isseps.usf.tn +21620228271 Cite Bahri 2 Rue 2007 N03
City Postal code Country Position/Affiliation
Sfax 3064 Tunisia PhD Student
REPORTING
Share IPD Description Additional Document Types Sharing Time Frame Key Access Criteria
Yes Individual participant data will not be made available for sharing. Study Protocol Not applicable; IPD will not be shared. Not applicable; individual participant data will not be made available.
URL Results Available Results Summary Result Posting Date First Journal Publication Date
No
Result Upload 1: Result Upload 2: Result Upload 3: Result Upload 4: Result Upload 5:
Result URL Hyperlinks Link To Protocol
Result URL Hyperlinks
Changes to trial information
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Actual trial start date 10/09/2026 PACTR Admin 01 Jun 2026