ROCKJAW® / SPORTS SCIENCE

THE SCIENCE OF THE BITE.

The published research on chewing resistance, the masseter and bite force, from professional wrestlers to the strength lab.

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Independent published studies are discussed. None of the featured studies tested ROCKJAW® Tuff Gum.

10 PUBLISHED STUDIES1995 TO 2025SOURCES VERIFIED 17.10.2026

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Chapters
  1. Overview
  2. Masseter
  3. The athlete data
  4. Chewing research
  5. Clenching & performance
  6. Focus & stress
  7. Evidence
  8. Studies
  9. FAQs

OVERVIEW / THE RESEARCH QUESTION

THREE QUESTIONS. TEN PAPERS.

How chewing resistance, masseter function and bite force connect to training, and what the research found in professional wrestlers and trained athletes.

  1. THE MUSCLE

    The masseter is one of the main jaw-closing muscles and a major contributor to bite force. [S1]

  2. THE RESISTANCE

    A controlled physiology study found that harder gum makes the masseter work harder. [S3]

  3. THE MEASUREMENT

    Controlled gum-chewing training studies recorded significant increases in maximum bite force. [S2] [S4]

ANATOMY / JAW-CLOSING MUSCLES

MEET THE MASSETER.

The masseter runs from the cheekbone arch to the angle of the jaw and is one of the main muscles that close the mouth. With the temporalis, it powers a hard bite.

Illustration of the masseter and temporalis muscles on the mandible Side view of the skull with the face to the left. The temporalis fans across the side of the head and narrows under the cheekbone arch onto the coronoid process of the mandible. The masseter runs from the cheekbone arch down and back to the angle of the mandible. An arrow at the molars marks the direction of bite force. Original illustration, not a clinical scan. TEMPORALIS MASSETER MANDIBLE BITE FORCE ZYGOMATIC ARCH
PLATE 01 Original ROCKJAW® illustration of the masseter, temporalis and mandible, side view.
NMaximum bite force
The greatest closing force a person produces between the teeth, in newtons. It is a strength output, measured with sensors or pressure-sensitive film, and reflects muscle strength, effort and tooth contact.
mmMasseter thickness
The depth of the muscle on ultrasound, in millimetres, at rest or while clenching. It is a size measure.
µVEMG / muscle activity
The electrical activity of the muscle while it works. It shows how hard the muscle is working right now.

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RESEARCH 01 / COMBAT SPORT

RESEARCH NOTE 01 / 2025 / CROSS-SECTIONAL / n = 34

PROFESSIONAL WRESTLERS BITE HARDER.

A 2025 comparison of 34 male wrestlers found that the 13 professionals had a higher mean bite force than the 21 non-professionals. The professionals also had a thicker masseter when clenching. [S1]

Mean maximum bite force (total), newtons

OBSERVATIONALBars: group mean from zero. Whiskers: ±1 SD.

Bar chart. Professional wrestlers, 13 people: mean bite force 1,071.7 newtons, standard deviation 380.2. Non-professional wrestlers, 21 people: mean 856.9 newtons, standard deviation 363.1. Difference 214.8 newtons, reported p = 0.032.

Professional wrestlersn = 131,071.7 N
Non-professional wrestlersn = 21856.9 N

Δ 214.8 N higher mean bite force in professionals: 25.1% above the non-professional mean

Measured between professional and non-professional athletes in the same sport.

Source: [S1] Lee et al., 2025, Table 2. Reported p = 0.032. Full text (opens in a new tab)
Bite force by group, S1 Table 2 (mean ± standard deviation, newtons)
GroupnMean (N)SD (N)
Professional wrestlers131,071.7380.2
Non-professional wrestlers21856.9363.1

MASSETER THICKNESS: AT REST VS CLENCHED

At rest, millimetres (S1 Table 2)

ProfessionalRight14.1 mm
ProfessionalLeft14.1 mm
Non-professionalRight13.1 mm
Non-professionalLeft13.1 mm

During clenching, millimetres (S1 Table 2)

ProfessionalRight16.8 mm
ProfessionalLeft16.2 mm
Non-professionalRight14.4 mm
Non-professionalLeft14.3 mm
Masseter thickness, S1 Table 2 (mean ± SD, mm). Resting and clenched values are separate series.
GroupSideAt rest (mm)Clenched (mm)
ProfessionalRight14.1 ± 1.8 16.8 ± 2.0
ProfessionalLeft14.1 ± 1.7 16.2 ± 1.8
Non-professionalRight13.1 ± 2.0 14.4 ± 1.8
Non-professionalLeft13.1 ± 1.8 14.3 ± 1.4

WHY THIS MATTERS

It is one of the few studies to measure bite force and masseter size in combat athletes, and the stronger bite belonged to the professionals.

RESEARCH 02 / STRENGTH AND FUNCTION

CHEWING TRAINING RAISED BITE FORCE.

Two controlled studies put people on a chewing programme and measured the result. Both recorded a significant rise in maximum bite force.

RESEARCH NOTE 02 / 2024 / RANDOMISED CONTROLLED TRIAL / n = 58

Six months of gum-chewing training in healthy adults [S2]

A randomised study of 58 healthy adults compared gum-chewing training with no training over six months. The gum-training group had significantly greater maximum occlusal force at three months.

  1. BASELINEForce, masseter thickness and jaw shape measured
  2. MONTH 1Force and thickness re-measured
  3. MONTH 3Maximum occlusal force significantly higher than baseline and than control (p < .001)
  4. MONTH 6Force, thickness and jaw shape re-measured

Timeline shows when outcomes were measured.

HOW IT WAS STUDIED
Design
Prospective randomised controlled trial, Yonsei University College of Dentistry, January to September 2020
People
58 healthy adults, randomly assigned to training or control
Protocol
Gum chewing three times a day for six months; control group had no training. Study method only, not a ROCKJAW use instruction.
Measured
Maximum occlusal force and masseter thickness at baseline, 1, 3 and 6 months; mandibular shape at baseline and 6 months
Found
Force significantly higher at 3 months (p < .001); occlusal contact area increased with force (p = .020).

RESEARCH NOTE 03 / 1995 / CONTROLLED TRAINING STUDY / n = 25

Four weeks of hard-gum chewing [S4]

OBSERVED

Maximum bite force increased significantly in the training group, peaked at the end of training and stayed higher two weeks after training stopped. The weakest starters gained most.

HOW IT WAS STUDIED
People
25 healthy adults: 17 in training (7 men, 10 women), 8 controls
Protocol
A special hard chewing gum, one hour daily for 28 days. Not a ROCKJAW use instruction.
Measured
Maximal bite force and endurance time during maximal clenching, before and after a fatigue test

RESEARCH 03 / IMMEDIATE MUSCLE DEMAND

RESEARCH NOTE 04 / 2024 / ACUTE PHYSIOLOGY / n = 11

MORE RESISTANCE. MORE WORK.

A 2024 short-term study had 11 healthy men chew three gums of different hardness for 120 seconds each, while researchers measured masseter activity, oxygenation, heart rate and perceived fatigue. The harder the gum, the harder the masseter worked: muscle activity, heart rate and perceived fatigue all rose significantly. [S3]

  • Masseter activity
  • Masseter oxygen saturation
  • Heart rate
  • Perceived masseter fatigue

In the study, as hardness increased, masseter activity, heart rate and perceived fatigue rose and oxygen saturation fell.

Low resistance. The jaw closes against little load; the muscle does comparatively little work per chew.

Medium resistance. A firmer bolus asks more of the jaw-closing muscles on every chew.

High resistance. In the study, the hardest of three gums produced the largest acute response.

CONCEPTUAL ILLUSTRATION.

RESEARCH 04 / CLENCHING AND FORCE

THE JAW. THE NERVOUS SYSTEM. THE FORCE.

Concurrent activation potentiation (CAP) is the extra force output measured elsewhere in the body while you deliberately clench your jaw. Four experiments measured it in jumps, strength tests and standing balance.

Clenching = a brief, deliberate bite during a lift or jump.Chewing training = weeks of repeated chewing.

OBSERVED IN EXPERIMENTS

2008 / ACUTE CROSSOVER / n = 14 [S5]

Countermovement jump, clenching on a mouthguard vs open mouth

Rate of force development
+19.5%
Time to peak force
20.15% shorter

2023 / REPEATED MEASURES / n = 12 [S6]

Highly trained rink-hockey athletes, isometric strength tests, clenching vs not clenching

Handgrip peak force
Higher p = 0.045
Bench-press peak force
Higher p = 0.018

2018 / REPEATED MEASURES / n = 36 [S7]

Isometric mid-thigh clean pull on a force platform, maximal jaw clench vs no clench

Peak force
Higher p ≤ 0.001
Rate of force development
Higher p = 0.001

2015 / POSTUROGRAPHY / n = 17 [S8]

Standing balance on firm and foam surfaces, light jaw clench (25% of maximum) vs habitual standing

Postural sway
Reduced
Postural stability
Improved

RESEARCH 05 / FOCUS AND STRESS

THE CHEW AND THE MIND.

Sport is won on reaction speed and composure as much as strength. Two controlled experiments measured what chewing gum does to both.

OBSERVED IN EXPERIMENTS

2013 / fMRI EXPERIMENT / n = 17 [S9]

Attention task in an MRI scanner, chewing flavourless gum vs not chewing

Mean reaction time
Faster
Attention and motor brain regions
More active

2009 / RANDOMISED CROSSOVER / n = 40 [S10]

Laboratory multi-tasking stress test, chewing gum vs not chewing

Salivary cortisol
Lower
Self-rated stress and anxiety
Lower
Alertness
Higher
Multi-tasking performance
Better

EVIDENCE / STRENGTH OF INFERENCE

WHAT WE KNOW.

Five kinds of evidence, in the order this page builds its case.

  1. 1ACUTE PHYSIOLOGY

    Harder gum increases the masseter's immediate workload. [S3]

    Design
    Controlled short-term experiment, 11 men
    What it can show
    An immediate, measurable muscle response to harder chewing.

  2. 2INTERVENTION RESEARCH

    Chewing programmes increased maximum bite force. [S2] [S4]

    Design
    Randomised controlled trial (58 adults) and a controlled training study (25 adults)
    What it can show
    A cause-and-effect link between a chewing programme and higher bite force.

  3. 3ATHLETE DATA

    Professional wrestlers had a higher bite force and a thicker clenched masseter. [S1]

    Design
    Cross-sectional comparison, 34 wrestlers
    What it can show
    A clear bite-force difference at the professional level of a combat sport.

  4. 4STRENGTH AND BALANCE EXPERIMENTS

    Clenching the jaw improved force and balance measures in the moment. [S5] [S6] [S7] [S8]

    Design
    Within-subject experiments, 12 to 36 people
    What it can show
    Immediate gains in force output, rate of force development and standing balance while clenching.

  5. 5FOCUS AND STRESS RESEARCH

    Chewing gum shortened reaction time and lowered stress markers. [S9] [S10]

    Design
    Controlled within-subject experiments, 17 and 40 adults
    What it can show
    Immediate effects of chewing on reaction speed, alertness, cortisol and performance under pressure.

MEET TUFF GUM.

Ultra-tough chewing gum from ROCKJAW®. Choose your flavour and your pack size.

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SAFETY / TRANSPARENCY

SCIENCE ISN'T A SHORTCUT.

Chewing tough gum is a physical load on your jaw, teeth and joints. Treat it with the same common sense as any training.

  • Soreness and fatigue. Hard chewing works the jaw muscles; tiredness or aching can follow, especially when you start.
  • Jaw joint (TMJ) problems. If you have jaw pain, clicking or a TMJ condition, speak to a dental professional before chewing tough gum. ROCKJAW's own FAQ advises chewing for only 5 to 10 minutes a day if you have TMJ.
  • Teeth, fillings and braces. Overuse can stress teeth and dental work. Avoid tough gum with braces or dental concerns unless a dental professional advises otherwise.
  • Children. Not recommended for children.
  • Stop if it hurts. Pain is a reason to stop and seek qualified advice, not to push through.

Follow each product's published guidance. Tuff Gum Performance contains caffeine; see its product page for the full important information.

RESEARCH DISCLOSURE

Last editorial review: 17 October 2026

Source verification: every study title, year, sample size and figure on this page was checked against its PubMed record on 16 and 17 October 2026. The wrestler charts use Table 2 of the full text [S1].

QUESTIONS

FAQS.

What does the masseter muscle do?

The masseter is one of the main muscles that close the jaw. It runs from the cheekbone arch to the outer surface and angle of the lower jaw, and works with the temporalis when you chew or bite. See Meet the masseter.

Does tougher gum make the masseter work harder?

In the short term, yes. Eleven healthy men chewed three gums of different hardness for 120 seconds each. As hardness increased, masseter activity, heart rate and perceived fatigue rose and muscle oxygen saturation fell [S3].

Can gum chewing increase bite force?

Yes. Controlled studies recorded significantly higher maximum bite force after a chewing programme: a 2024 randomised trial at three months [S2], and a 1995 study after 28 days of hard-gum chewing [S4].

Can chewing gum help focus and stress?

Two controlled experiments say it can. Chewing gum significantly shortened mean reaction time in an attention task [S9], and under a laboratory stress test it was linked to better alertness, lower stress and anxiety, lower salivary cortisol and better multi-tasking performance [S10]. See The chew and the mind.

What is concurrent activation potentiation?

It is the extra force output measured elsewhere in the body while you deliberately clench your jaw. In experiments, clenching raised rate of force development in a jump [S5], peak force in grip, bench-press and clean-pull tests [S6] [S7], and improved standing balance [S8]. See Clenching and performance.

Can chewing hurt the jaw or teeth?

It can. Overuse may cause jaw discomfort or aggravate joint problems, and hard chewing loads teeth and dental work. Avoid tough gum if you have jaw pain, TMJ problems, dental concerns or braces unless a dental professional advises otherwise, and stop if pain develops. See Science isn't a shortcut.

Where can I read the original scientific papers?

Every paper is listed in the research library with PubMed and DOI links. Two have free full text: [S1] and [S6].

STUDIES / RESEARCH LIBRARY

READ THE ORIGINAL PAPERS.

Every study cited on this page, with its sample, what it measured and what it found. External links open the journal or PubMed record in a new tab.

  1. [S1]2025Cross-sectional comparison (observational)n = 34

    Adaptations of bite force and masseter muscle thickness to high-intensity physical training in professional athletes: a comparative cross-sectional study

    Kyu-Lim Lee, Jun-Young Sung, Soo-Bin Kim, Hee-Jin Kim. BMC Sports Science, Medicine and Rehabilitation 2025;17:177. Published 3 July 2025.

    Population
    34 male wrestlers in Korea: 13 professional (registered with the Korean Sports and Olympic Committee) and 21 non-professional
    Measured
    Bite force with pressure-sensitive film; masseter thickness at rest and while clenching by ultrasonography
    Key result
    Professionals had higher mean bite force (1,071.7 N vs 856.9 N, p = 0.032) and greater masseter thickness during clenching.
    Study details
    Intervention
    Professional and non-professional groups compared at a single time point.
    Results
    Mean bite force 1,071.7 N (SD 380.2) in professionals vs 856.9 N (SD 363.1) in non-professionals, p = 0.032. Clenched masseter thickness was greater in professionals (Table 2).
    Interpretation
    A clear bite-force advantage at the professional level of a combat sport.
    Evidence type
    Athlete association
    Verified
    2026-10-16

    PubMed record for S1 (external site, opens in a new tab) DOI for S1 (external site, opens in a new tab) Free full text for S1 (external site, opens in a new tab)

  2. [S2]2024Randomised controlled trialn = 58

    Effects of gum chewing training on occlusal force, masseter muscle thickness and mandibular shape: A randomised controlled clinical trial

    Hyo-Jung Jung, Na Kyung Hwangbo, Younjung Park, Hyung-Joon Ahn. Journal of Oral Rehabilitation 2024;51(12):2529-2536. Published December 2024 (online 30 August 2024).

    Population
    58 healthy adults, randomised to gum-chewing training or no training (Yonsei University College of Dentistry, 2020)
    Measured
    Maximum occlusal force and masseter muscle thickness at baseline, 1, 3 and 6 months; mandibular shape at baseline and 6 months
    Key result
    Maximum occlusal force rose significantly at three months in the gum-training group.
    Study details
    Intervention
    Gum chewing three times a day for six months; control group received no training
    Results
    At three months the training group's mean maximum occlusal force was significantly higher than at baseline and significantly higher than control (p < .001). Occlusal contact area rose with force (p = .020).
    Interpretation
    Three months of gum-chewing training significantly increased maximum bite force.
    Evidence type
    Intervention research
    Verified
    2026-10-16

    PubMed record for S2 (external site, opens in a new tab) DOI for S2 (external site, opens in a new tab)

  3. [S3]2024Short-term physiology experimentn = 11

    Effects of Different Gum Hardness on Masseter Muscle Activity During Gum Chewing: An NIRS Oximetry Study

    Takahiro Sakaue, Arata Tsutsui, Shinji Togo, Tomotaka Takeda, Kazunori Nakajima, Kenichi Fukuda. Advances in Experimental Medicine and Biology 2024;1463:341-345. Published 2024.

    Population
    11 healthy adult men
    Measured
    Masseter tissue oxygenation (NIRS), muscle activity, heart rate and perceived masseter fatigue (visual analogue scale)
    Key result
    Harder gum produced a larger acute workload in the masseter.
    Study details
    Intervention
    120 seconds of chewing with each of three gums of different hardness
    Results
    As hardness increased, masseter oxygen saturation fell, deoxyhaemoglobin rose, and muscle activity, heart rate and perceived fatigue all increased significantly.
    Interpretation
    Harder gum means more work for the masseter.
    Evidence type
    Acute physiology
    Verified
    2026-10-16

    PubMed record for S3 (external site, opens in a new tab) DOI for S3 (external site, opens in a new tab)

  4. [S4]1995Controlled training studyn = 25

    Effects of fatigue and chewing training on maximal bite force and endurance

    S Kiliaridis, M G Tzakis, G E Carlsson. American Journal of Orthodontics and Dentofacial Orthopedics 1995;107(4):372-378. Published April 1995.

    Population
    25 healthy adults: training group 17 (7 men, 10 women), control group 8 (4 men, 4 women)
    Measured
    Maximal bite force and endurance time during maximal clenching, before and after a fatigue test
    Key result
    Maximal bite force increased in the hard-gum training group.
    Study details
    Intervention
    Training group chewed a special hard chewing gum for one hour daily for 28 days (study protocol; not a ROCKJAW use instruction)
    Results
    Maximal bite force rose significantly by mid-study (p < 0.05), peaked at the end of training (p < 0.001) and stayed high two weeks later. People with the weakest starting values gained most.
    Interpretation
    Hard-gum training raised maximal bite force, and the gain held two weeks after training stopped.
    Evidence type
    Intervention research
    Verified
    2026-10-16

    PubMed record for S4 (external site, opens in a new tab) DOI for S4 (external site, opens in a new tab)

  5. [S5]2008Acute crossover experimentn = 14

    Jaw clenching results in concurrent activation potentiation during the countermovement jump

    William P Ebben, Eamonn P Flanagan, Randall L Jensen. Journal of Strength and Conditioning Research 2008;22(6):1850-1854. Published November 2008.

    Population
    14 subjects
    Measured
    Rate of force development, time to peak force and peak force
    Key result
    Clenching on a mouthguard produced a 19.5% greater rate of force development in a jump.
    Study details
    Intervention
    Countermovement jump on a force platform while maximally clenching on a dental vinyl mouthguard vs jumping with an open mouth
    Results
    Rate of force development was 19.5% greater and time to peak force 20.15% shorter with clenching (both p < 0.05).
    Interpretation
    Clenching sped up force production in an explosive jump.
    Evidence type
    Indirect sport experiment
    Verified
    2026-10-16

    PubMed record for S5 (external site, opens in a new tab) DOI for S5 (external site, opens in a new tab)

  6. [S6]2023Randomised repeated-measures experimentn = 12

    Acute effects of jaw clenching while wearing a customized bite-aligning mouthguard on muscle activity and force production during maximal upper body isometric strength

    Adrià Miró, Bernat Buscà, Jordi Arboix-Alió, Pol Huertas, Joan Aguilera-Castells. Journal of Exercise Science and Fitness 2023;21(1):157-164. Published January 2023 (online 26 December 2022).

    Population
    12 highly trained rink-hockey athletes
    Measured
    Peak force and muscle activity in isometric handgrip, bench press and biceps curl
    Key result
    Clenching produced greater peak force in handgrip and bench press than not clenching.
    Study details
    Intervention
    Three conditions: clenching with a customised mouthguard, clenching without a mouthguard, no clenching
    Results
    Clenching without a mouthguard vs no clenching: higher peak force in handgrip (p = 0.045) and bench press (p = 0.018).
    Interpretation
    Clenching lifted peak force in grip and bench-press tests in highly trained athletes.
    Evidence type
    Indirect sport experiment
    Verified
    2026-10-16

    PubMed record for S6 (external site, opens in a new tab) DOI for S6 (external site, opens in a new tab) Free full text for S6 (external site, opens in a new tab)

  7. [S7]2018Repeated-measures experimentn = 36

    Effects of Jaw Clenching and Jaw Alignment Mouthpiece Use on Force Production During Vertical Jump and Isometric Clean Pull

    Charles R Allen, Yang-Chieh Fu, Vanessa Cazas-Moreno, Melinda W Valliant, Jacob R Gdovin, Charles C Williams, John C Garner. Journal of Strength and Conditioning Research 2018;32(1):237-243. Published January 2018.

    Population
    36 male subjects
    Measured
    Peak force, normalised peak force and rate of force development
    Key result
    Maximal jaw clenching improved peak force and rate of force development in the isometric clean pull.
    Study details
    Intervention
    Maximal isometric mid-thigh clean pull and countermovement jump on a force platform, with and without maximal jaw clenching, across three mouthpiece conditions
    Results
    In the isometric clean pull, maximal jaw clenching improved peak force (p ≤ 0.001), normalised peak force (p ≤ 0.001) and rate of force development (p = 0.001), regardless of mouthpiece condition.
    Interpretation
    The authors conclude that jaw clenching can produce concurrent activation potentiation and an ergogenic effect in high-force activities.
    Evidence type
    Strength and balance experiment
    Verified
    2026-10-17

    PubMed record for S7 (external site, opens in a new tab) DOI for S7 (external site, opens in a new tab)

  8. [S8]2015Within-subject posturography experimentn = 17

    Postural stability and the influence of concurrent muscle activation: Beneficial effects of jaw and fist clenching

    Steffen Ringhof, Timo Leibold, Daniel Hellmann, Thorsten Stein. Gait & Posture 2015;42(4):598-600. Published October 2015.

    Population
    17 healthy young adults
    Measured
    Centre-of-pressure displacement (postural sway)
    Key result
    Submaximal jaw clenching significantly improved standing postural stability.
    Study details
    Intervention
    Standing on firm and foam surfaces while clenching the jaw at 25% of maximum voluntary contraction, guided by real-time EMG, compared with habitual standing
    Results
    Centre-of-pressure displacements were significantly reduced during submaximal jaw clenching compared with habitual standing.
    Interpretation
    The authors describe beneficial effects of jaw clenching for static postural control.
    Evidence type
    Strength and balance experiment
    Verified
    2026-10-17

    PubMed record for S8 (external site, opens in a new tab) DOI for S8 (external site, opens in a new tab)

  9. [S9]2013Within-subject fMRI experimentn = 17

    Effects of chewing on cognitive processing speed

    Yoshiyuki Hirano, Takayuki Obata, Hidehiko Takahashi, Atsumichi Tachibana, Daigo Kuroiwa, Toru Takahashi, Hiroo Ikehira, Minoru Onozuka. Brain and Cognition 2013;81(3):376-381. Published April 2013.

    Population
    17 healthy adults aged 20 to 34
    Measured
    Reaction time and brain activation (BOLD fMRI)
    Key result
    Chewing gum significantly shortened mean reaction time in an attention task.
    Study details
    Intervention
    Two back-to-back attentional network test sessions in a 3.0 T MRI scanner, with and without chewing odourless, tasteless gum
    Results
    Mean reaction time was significantly decreased in the chewing condition, regardless of speed-accuracy trade-off. Chewing produced higher activation in the anterior cingulate cortex and left frontal gyrus and in motor-related regions.
    Interpretation
    The authors suggest chewing raised arousal and alertness, leading to faster cognitive processing.
    Evidence type
    Focus and stress research
    Verified
    2026-10-17

    PubMed record for S9 (external site, opens in a new tab) DOI for S9 (external site, opens in a new tab)

  10. [S10]2009Randomised crossover experimentn = 40

    Chewing gum alleviates negative mood and reduces cortisol during acute laboratory psychological stress

    Andrew Scholey, Crystal Haskell, Bernadette Robertson, David Kennedy, Anthea Milne, Mark Wetherell. Physiology & Behavior 2009;97(3-4):304-312. Published June 2009.

    Population
    40 participants, mean age 21.98 years
    Measured
    Salivary cortisol, state anxiety, self-rated stress, mood and alertness, and multi-tasking performance
    Key result
    Chewing gum reduced salivary cortisol and stress and improved alertness and performance under pressure.
    Study details
    Intervention
    A multi-tasking stress framework at two intensities, on separate days, while chewing gum and while not chewing
    Results
    During both levels of stress, chewing gum was associated with significantly better alertness and reduced state anxiety, stress and salivary cortisol. Overall multi-tasking performance was also significantly better while chewing.
    Interpretation
    Chewing gum improved both how people felt and how they performed under acute stress.
    Evidence type
    Focus and stress research
    Verified
    2026-10-17

    PubMed record for S10 (external site, opens in a new tab) DOI for S10 (external site, opens in a new tab)

Editorial method. Studies were selected for direct relevance to chewing resistance, bite force, masseter function, jaw clenching, focus and stress in sport. Each figure was checked against the PubMed record, and against the full text where it is freely available.

Last research review: 17 October 2026

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