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.