Apr 19 / Geoff Linsday

Bath Indices Explained: Track Your Axial SpA

How to Use the Bath Indices to Assess and Manage Your AS


Living with Axial Spondyloarthritis (AS) means tuning in regularly to how your body is doing. That’s where the Bath Indices come in – a globally recognised set of four assessments that help you track your AS symptoms, function, mobility, and general wellbeing over time.


They’re simple enough to do at home, and incredibly useful when it comes to self-managing your AS, adapting your yoga practice, and having more informed conversations with your healthcare team.


Table of Contents:

1. What Are the Bath Indices?


2. Why Use the Bath Indices for AS Self-Care?


3. The Four Bath Indices Explained

  • 1. BASDAI

  • 2. BASFI

  • 3. BAS-G

  • 4. BASMI


4. How to Measure BASMI at Home


5. Next Steps After Recording Your Scores

6. Final Thoughts

What Are the Bath Indices?

The Bath Indices are a set of four assessments developed through research and used globally to measure the impact of AS. Three are self-assessments, and one requires basic physical measurements with help.


Together, they give you a personal AS score out of 10 that helps you track your condition over time.


A score of 2/10: doing really well


A score of 7/10: symptoms are more active


➡️ Download the Bath Indices booklet from NASS

Why Use the Bath Indices for AS Self-Care?

  • Empowering: You can complete them yourself
  • Insightful: They provide a clear picture of how you're doing
  • Yoga-ready: Help determine what kind of yoga practice is suitable
  • Useful for healthcare: Great to share with your Rheumatologist
  • Trackable: Watch your progress or changes over time

They’re not just for professionals anymore – they’re tools for patients, too.

The Four Bath Indices Explained

1. BASDAI

6 questions about symptom severity in the past week, including pain and fatigue.

2. BASFI

10 questions about your ability to manage daily activities, from bending to getting dressed.

3. BAS-G

2 questions about your general wellbeing over the past week and the past 6 months.

All of the above are quick self-assessments you can do on your own.

4. BASMI

This mobility index involves 5 physical measurements. You’ll need a helper and a few basic tools.

Scores are based on:

  • Spinal posture

  • Side bending

  • Forward bending

  • Leg spread

  • Neck rotation

📺 Watch this guide on how to measure BASMI

How to Measure BASMI at Home

① Posture – Stand against a wall. Measure from your ear (tragus) to the wall.

② Side bend – Measure how far your fingers move toward the floor when leaning sideways.

③ Forward bend – Mark and measure spinal movement as you bend forward.

④ Leg spread – Lie down and measure the distance between your ankles.

⑤ Neck turn – Use a paper goniometer or phone app to track how far your head turns left and right.

These give you a movement score that contributes to your overall AS score.


Next Steps After Recording Your Scores




These assessments help you and your Rheumatology team make better decisions together – including what kind of yoga is safe and beneficial for you.

Final Thoughts


The Bath Indices give you more than just numbers – they give you insight, control, and a stronger foundation for self-care. Yoga for AS is here to help you use those insights to move better, feel stronger, and live well.

If you would like to practice Yoga for AS, you can explore a Live Online Class or the Virtual Library.


Both of which you can try for free below.

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