What is Headshaking?

Headshaking is a repetitive, involuntary or voluntary movement where the horse vigorously shakes, tosses, or jerks their head—typically in a vertical (up and down) or horizontal (side to side) motion. The behaviour can range from occasional mild tosses to violent, continuous shaking that makes the horse difficult or dangerous to ride. While headshaking can have multiple causes (including medical conditions like trigeminal neuralgia, allergies, ear mites, or light sensitivity), incorrectly fitting bits and bridles are significant and often overlooked contributors.

Types of Headshaking Related to Equipment

Vertical Headshaking (Up and Down)

The horse repeatedly throws their head upward and downward in sharp, often violent motions. This is frequently associated with:

Poll and Headpiece Pressure:

• Headpiece sitting too low or directly on the atlas vertebra (first cervical vertebra)
• Insufficient clearance around the ears, with the headpiece pressing against their base
• Too-narrow headpiece concentrating pressure on the sensitive poll area
• Browband too short, pulling the headpiece forward into the ears

Bit-Related Causes:

• Excessive palate pressure from thick bits in horses with low palates
• Bit positioned too high, creating constant pressure and wrinkles at the mouth corners
• Nutcracker action from single-jointed bits causing tongue compression and upward pressure into the palate

The upward head toss is an attempt to relieve pressure at the poll or to create space in the mouth by opening it and moving away from the bit.

Horizontal Headshaking (Side to Side)

The horse shakes their head from side to side, sometimes violently, as if trying to dislodge something. This is often related to:

Facial and Noseband Issues:

• Noseband pressing on facial nerves running along the sides of the face
• Noseband positioned too high, putting pressure on prominent cheekbones
• Uneven or twisted noseband creating one-sided pressure
• Flash strap or drop noseband positioned incorrectly, causing irritation

Bit and Bridle Asymmetry:

• Cheekpieces adjusted to different lengths, creating uneven pressure
• Bit width incorrect, causing the bit to slide side to side or pinch unevenly
• Browband sitting at an angle rather than level, pulling the bridle asymmetrically

The side-to-side motion is an attempt to shake off or escape the irritating pressure or to relieve nerve irritation.

Combination or Rotational Headshaking

Some horses display complex headshaking patterns—circular motions, figure-eight patterns, or alternating between vertical and horizontal. This often indicates multiple sources of discomfort or severe irritation that the horse is desperately trying to escape.

Specific Equipment Issues That Trigger Headshaking

Poll and Headpiece Problems

Anatomical Sensitivity: The poll region contains critical structures—the atlantooccipital joint (where the skull meets the first vertebra), major nerve pathways, sensitive ligament attachments, and minimal soft tissue padding. Traditional straight headpieces create concentrated pressure directly on this sensitive area.

How It Causes Headshaking: When rein contact is taken up, pressure transmits through the bit and cheekpieces to the headpiece, compressing the poll. Horses experiencing this discomfort shake their heads trying to relieve the pressure or avoid contact that intensifies it. The behaviour often worsens when working in an outline or during collected work where poll flexion increases headpiece pressure.

Signs This Is the Cause:

• Headshaking worsens when contact is taken up or increased
• Behaviour intensifies during collected work or when poll flexion is requested
• Horse is sensitive to touch or palpation behind the ears and over the poll
• Visible pressure marks, heat, or swelling in the poll area after riding
• Horse resists bridling, particularly when the headpiece goes over the ears

Browband Issues

The Pressure Point: A browband that's too short pulls the headpiece forward into the base of the ears with every movement, creating constant irritation and pressure. Even slight movement of the head increases this pulling sensation.

How It Causes Headshaking: The horse shakes their head attempting to reposition the browband or relieve the pressure at the ear base. This creates a vicious cycle—the shaking movement temporarily relieves pressure, so the behaviour is reinforced, but the movement also causes the browband to pull even more.

Signs This Is the Cause:

• Visible gaps between the forehead and browband are absent—the browband sits tight against the head
• The headpiece is visibly pulled forward, sitting on or in front of the ears rather than behind them
• Ears are pinned back or pulled forward by the browband tension
• Horse shows sensitivity when the browband area is touched
• Headshaking occurs consistently throughout riding, not just when contact is taken

Noseband Pressure and Positioning

Nerve Interference: The facial nerve runs along the side of the horse's face, passing close to where nosebands sit. Pressure on this nerve creates genuine neurological irritation—not just discomfort but actual nerve interference that can cause tingling, numbness, or pain.

How It Causes Headshaking: Nerve irritation creates an almost irresistible urge to shake the head, similar to how humans shake our hands when they "fall asleep" from nerve compression. The horse cannot articulate "my face is numb and tingling," so they shake their head trying to relieve the sensation.

Specific Noseband Issues:

• Too tight: Creates excessive pressure and potential nerve compression
• Too high: Sits on or near the prominent cheekbones and facial nerve pathways
• Twisted or uneven: Creates one-sided pressure causing asymmetric headshaking
• Wrong design for the horse's face shape: Doesn't follow natural contours, creating pressure points

Signs This Is the Cause:

• Headshaking is predominantly side-to-side
• Behaviour begins or worsens shortly after the noseband is fastened
• Horse shows improvement if the noseband is loosened or removed during work
• Visible marks, indentations, or sensitivity along the noseband area
• The horse rubs their face against objects when possible

Bit-Related Headshaking

Mouth Discomfort: Bits that pinch lips, create excessive tongue or bar pressure, contact the palate, or are simply uncomfortable trigger headshaking as the horse tries to reposition the bit or escape the sensation.

Common Bit Problems Causing Headshaking:

• Wrong width: Too narrow (pinching) or too wide (sliding and unstable)
• Wrong thickness: Too thick for the mouth size, creating palate contact or tongue compression
• Sharp edges or joints: Creating pinching or sharp pressure points
• Incorrect positioning: Too high or too low, affecting how it sits in the mouth
• Inappropriate severity: Too harsh for the horse's sensitivity level

How It Manifests:

• Headshaking when contact is first taken up
• Increased shaking when rein aids are applied or during transitions
• Head tossing combined with mouth opening, tongue evasions, or jaw crossing
• Immediate improvement when the bit is removed

Temperature and Material Sensitivities

Some horses shake their heads in response to:

• Cold bits placed in the mouth suddenly (particularly metal bits in winter)
• Material sensitivities to certain metals or synthetic materials
• Taste aversions to bit materials or coatings

While less common than fit issues, these can contribute to headshaking behaviour.

Distinguishing Equipment-Related Headshaking from Other Causes

When to Suspect Bit/Bridle Fit

Equipment is likely contributing if:

• Headshaking begins when tacked up or immediately when ridden
• Behaviour worsens with increased contact or during specific movements
• The horse is fine when worked in a halter, bitless bridle, or different equipment
• There are visible marks, sensitivity, or physical signs where equipment sits
• Changing or adjusting equipment produces immediate improvement
• The behaviour is consistent and predictable based on equipment use

When Other Causes Are More Likely

Consider non-equipment causes if:

• Headshaking occurs even when not ridden or wearing equipment
• Behaviour is seasonal (suggesting allergies or light sensitivity)
• The horse shakes their head in the field or stable
• Veterinary examination reveals ear problems, dental issues, or neurological conditions
• The behaviour began suddenly without equipment changes and persists despite equipment modifications

The Investigation Process

A systematic approach is essential:

1. Veterinary examination: Rule out medical causes (trigeminal neuralgia, ear mites, dental problems, vision issues)
2. Equipment assessment: Professional evaluation of all tack fit
3. Systematic testing: Try different bits, bridle designs, noseband styles; work without certain components
4. Environmental factors: Note if behaviour changes with season, light conditions, or location
5. Video analysis: Record the horse working to identify patterns and triggers

Solutions When Equipment Is the Cause

Bridle Modifications

For Poll Pressure:

• Switch to anatomical headpieces with cut-outs around ears and wider, padded designs
• Ensure the browband is correctly sized—not too short
• Use bridles specifically designed to reduce poll pressure
• Consider padded or gel-padded headpieces

For Noseband Issues:

• Ensure correct positioning—two finger-widths below the prominent cheekbone
• Check tightness—should accommodate two fingers comfortably
• Try anatomical nosebands with cut-outs that avoid facial nerve pathways
• Consider whether the horse actually needs a noseband or if removing it helps
• Experiment with different noseband styles (cavesson vs. flash vs. drop) to find what suits the individual horse

For Overall Fit:

• Have a professional bridle fitter assess the entire bridle system
• Ensure all components are adjusted symmetrically
• Check that nothing is twisted, worn, or damaged
• Verify all buckles and hardware are smooth without sharp edges

Bit Changes

Selection Considerations:

• Professional bit fitting to assess mouth conformation
• Try different widths, thicknesses, and designs systematically
• Consider double-jointed or curved bits to reduce nutcracker action
• Explore different materials (sweet iron, copper, rubber, plastic)
• Ensure bit height is correct—creating 1-2 gentle wrinkles at the mouth corners

Alternative Approaches:

• Trial bitless bridles or hackamores if bit discomfort is severe
• Use softer, thicker bits for horses with bar sensitivity
• Try bits with tongue relief for horses with large tongues or low palates

Prevention and Ongoing Management

Regular Assessment

• Annual (minimum) professional bridle and bit fitting checks
• Reassess whenever the horse's shape, work level, or behaviour changes
• Check equipment condition regularly—leather stretches, stitching fails, metal wears
• Palpate the horse's poll, face, and mouth areas regularly for sensitivity or changes

Proper Adjustment

• Take time to adjust bridles correctly before each ride
• Ensure browband isn't too short, noseband isn't too tight, bit height is correct
• Check that everything sits symmetrically and comfortably
• Allow the horse time to accept the bit before mounting (warm the bit in cold weather)

Listen to Your Horse

Headshaking is communication. Rather than using gadgets or training methods to suppress the behaviour, investigate the cause. Your horse is telling you something is wrong—the ethical response is to find out what and address it.

The Bottom Line

While headshaking can have complex, multifactorial causes, incorrectly fitting bits and bridles are significant, addressable contributors that should always be investigated. Many horses diagnosed with "idiopathic headshaking" (unknown cause) improve dramatically when equipment fit is properly addressed.

Your horse cannot tell you in words that their bridle hurts, but headshaking is a clear, physical communication that something is wrong. Professional assessment of bit and bridle fit should be an early step in investigating any headshaking behaviour—it's non-invasive, relatively inexpensive compared to extensive veterinary work-ups, and often provides immediate answers and relief.

If your horse shakes their head, don't accept it as a quirk or bad habit. Investigate thoroughly, starting with the equipment you're asking them to wear.