Can you consciously relax the internal anal sphincter?

Not directly. The internal anal sphincter is an involuntary smooth muscle — you cannot relax it the way you would relax your shoulders or unclench your fist. However, you can influence it indirectly. Deep breathing, warm water, and reducing overall body tension all affect the autonomic nervous system that controls the internal sphincter. The techniques on this page work through that indirect pathway.

What causes the internal sphincter to tighten?

The most common cause in the context of fissures is the pain-spasm cycle. A tear in the anal lining triggers the sphincter to tighten as a protective response. This tightening reduces blood flow, slows healing, and makes the next bowel movement more likely to re-injure the area — which triggers more tightening. Stress, anxiety, and general body tension can also increase sphincter tone.

Do warm baths actually relax the sphincter?

Yes — warm water is the most consistently reported technique. Warmth increases blood flow and helps smooth muscles release tension. Most people describe 10 to 20 minutes in comfortably warm water as effective, particularly after a bowel movement when spasm tends to be worst.

How long does it take for sphincter relaxation techniques to work?

Individual techniques like a warm bath provide temporary relief during and for a short time after use. Sustained improvement — a lower baseline level of sphincter tension — typically takes one to two weeks of consistent practice. People describe the cumulative effect as more significant than any single session.

What is the difference between the internal and external sphincter?

The external sphincter is a voluntary muscle — the one you consciously squeeze when you hold a bowel movement. The internal sphincter is involuntary — it maintains a constant resting tone without your awareness. In fissures, it is the internal sphincter that spasms and contributes to the pain cycle. The techniques on this page target the internal sphincter indirectly through the autonomic nervous system.

How to relax the internal anal sphincter

At a glance

The internal anal sphincter is at the heart of the fissure pain cycle. When it tightens — which it does involuntarily in response to pain — it reduces blood flow, slows healing, and makes every bowel movement more likely to re-injure the area. Learning to influence that muscle, even partially, is one of the most practical things people describe doing during fissure recovery.

This guide covers why the sphincter tightens, the techniques people report using to ease it, how those techniques connect to each other, and when self-care needs to be supplemented with medical treatment.

The key concept: you cannot directly relax the internal sphincter the way you relax a clenched hand. It is an involuntary smooth muscle. But you can influence it indirectly — through warmth, breathing, body positioning, stress reduction, and in some cases, medication. Understanding that distinction makes the techniques more effective, because you stop trying to force something that cannot be forced and start working with your body’s own systems.

Why the sphincter tightens

The internal sphincter maintains a constant resting tone — a baseline level of tension that keeps the anal canal closed. This is normal and essential. The problem in fissures is that this resting tone becomes elevated. The muscle is tighter than it needs to be, and it stays tight.

Here is the cycle people describe:

A fissure forms — a small tear in the anal lining
Pain from the tear triggers the sphincter to tighten further as a protective response
The tightened muscle compresses the blood vessels that supply the area
Reduced blood flow means the tissue cannot get the oxygen and nutrients it needs to heal
The next bowel movement passes through a tighter opening, re-injuring the tear
More pain triggers more tightening

This cycle — pain, spasm, reduced blood flow, slow healing, re-injury — is what makes fissures so persistent and so frustrating. Breaking it, or at least reducing it, is the goal of sphincter relaxation.

Warm water

Warmth is the most consistently reported technique for sphincter relaxation. It works by increasing blood flow and triggering smooth muscle relaxation through the local effect of heat on tissue.

Sitz baths

Sitting in comfortably warm water for 10 to 20 minutes is the most common approach. People describe:

Using a sitz bath basin that fits over the toilet or sitting in a shallow bath
Water that is warm but not hot — hot enough to be soothing, cool enough that it would not redden the skin on your inner wrist
2 to 3 baths per day during active symptoms, particularly after bowel movements
A noticeable easing of tightness during the soak that lasts for a period afterward

The effect is temporary. But regular sitz baths throughout the day can keep the sphincter at a more manageable level of tension. People describe the cumulative effect over days and weeks as significant.

For a full routine, see our sitz bath guide.

Warm compresses

When a full sitz bath is not practical — at work, during the night, between scheduled baths — a warm compress provides a similar principle on a smaller scale:

A clean cloth soaked in warm water, wrung out, held gently against the area
10 to 15 minutes, rewarming the cloth as needed
A warm water bottle wrapped in a towel, held in position while lying on one side

The effect is less thorough than a sitz bath but practical and accessible.

Breathing techniques

This is the technique people describe as hardest to learn and most useful in the long run. It works through the autonomic nervous system — the system that controls involuntary functions including the internal sphincter.

The mechanism

Deep, slow exhalation activates the parasympathetic nervous system — the body’s “rest and digest” mode. This promotes relaxation in smooth muscles throughout the body, including the internal sphincter. It works against the sympathetic (“fight or flight”) activation that tightens muscles when you are in pain or anxious.

What people describe doing

Slow breathing: Inhaling gently through the nose for 4 to 5 seconds, exhaling slowly through the mouth for 6 to 8 seconds. The long exhalation is the important part.
Not holding the breath: During bowel movements, the instinct is to hold the breath and brace. This increases abdominal pressure and tightens the pelvic floor — including the sphincter. Breathing out slowly during the effort works against that reflex.
Releasing the jaw and shoulders: Tension in the upper body mirrors tension in the pelvic floor. Consciously unclenching the jaw and dropping the shoulders helps the whole body release.
Practising outside the bathroom: The more familiar the breathing pattern becomes, the easier it is to use when it matters most. People describe practising while sitting at a desk, lying in bed, or during a walk.

Building the habit

This does not come naturally, especially when bowel movements are associated with pain. People describe it as a skill that takes one to two weeks of daily practice before it starts to feel automatic. The initial awkwardness gives way to something that eventually feels like second nature.

Body positioning

How you sit on the toilet affects the angle of the anal canal and the degree of effort required to pass stool.

The squat position

When the knees are raised above the hips, the puborectalis muscle relaxes and the anorectal angle straightens. This means:

Less straining is needed
The stool passes through a more open channel
The sphincter is not forced open against its own tension
Reactive spasm is less likely to be triggered

Most people achieve this with a toilet footstool — a step placed in front of the toilet that raises the knees. Combined with a slight forward lean (forearms resting on thighs), this creates the position that people describe as most comfortable.

People sometimes describe the footstool as a small change with a disproportionate impact.

Stress and the sphincter

The internal sphincter does not exist in isolation. It is part of the pelvic floor, which is influenced by overall body tension, stress levels, and emotional state. People who deal with chronic sphincter spasm consistently describe a connection between their stress levels and their symptoms.

What people report noticing

Symptoms are worse during high-stress periods — work deadlines, relationship difficulties, health anxiety
Poor sleep leads to a tighter baseline the following day
Anxiety about the fissure itself feeds the tension cycle — worrying about pain creates the tension that contributes to pain
General relaxation practices — walking, meditation, progressive muscle relaxation — have a noticeable effect on anal symptoms

This connection is not imaginary. The pelvic floor muscles are innervated by the same nervous system that responds to stress. When the body is in a stressed state, muscles tighten — including those in the pelvis.

Practical approaches

Movement: Gentle walking is the most commonly mentioned. Sitting for long periods increases pelvic floor tension. Regular movement helps.
General relaxation: Progressive muscle relaxation, meditation apps, or simply sitting quietly. People describe these as surprisingly relevant.
Limiting symptom research: Anxiety about the condition feeds the tension cycle. Finding a balance between being informed and being consumed by worry matters.
Sleep: Several people describe a direct link between poor sleep and worse symptoms.

When self-care needs support

These techniques help. But they have limits.

What they can do

Temporarily reduce sphincter spasm and improve blood flow
Make bowel movements less painful
Support healing by improving the conditions the body needs to repair
Work alongside medical treatments to improve their effectiveness
Provide something practical and within your control

What they cannot do

Guarantee healing — some fissures, especially chronic ones, need more
Replace medical treatment when it is needed
Work instantly — the effect builds over days and weeks of consistency

Medical options for sphincter relaxation

If consistent self-care over several weeks is not producing improvement, there are medical approaches that specifically target sphincter relaxation:

Topical treatments — prescription ointments such as GTN or diltiazem that relax the sphincter pharmacologically. These are applied directly and work locally. See our topical treatments guide.
Botox injection — temporarily reduces sphincter tone by blocking nerve signals to the muscle. The effect lasts weeks to months, allowing the fissure time to heal. See our Botox guide.
Pelvic floor physiotherapy — a specialist assessment of muscle function with targeted techniques including biofeedback, manual therapy, and exercises. See our pelvic floor guide.
Lateral internal sphincterotomy (LIS) — a small surgical cut to the internal sphincter that permanently reduces its resting tone. This is typically reserved for chronic fissures that have not responded to other treatments. See our LIS surgery guide.

These options exist because self-care does not work for everyone. Needing medical support is not a failure of effort or discipline — it is a reflection of how some fissures behave. The self-care techniques on this page remain valuable alongside medical treatment and often enhance its effectiveness.

Putting it together

Sphincter relaxation is not a single technique. It is a combination of approaches used consistently:

Warm water for direct relaxation of the muscle
Breathing for activating the parasympathetic nervous system
Positioning for reducing the effort needed during bowel movements
Stress management for lowering the baseline tension level
Soft stools for minimising the strain that triggers reactive spasm — see our stool softening foods guide and diet guide

People who describe the best results use several of these together, consistently, over weeks. No single technique is a solution on its own. The combination, sustained over time, is what makes the difference.