Inflammation doesn't mean stop.

You were told to rest. That was not wrong. But it was not the whole truth.

Imagine you are thirty-two, and you have just been diagnosed with something that finally explains years of symptoms. Your immune system is attacking your own tissue. The doctor says: reduce your stress. Rest when you need to. Don't overdo it. This advice is given with care, and parts of it are correct. But what often gets left out of that conversation is what your muscles do when you contract them. Not in spite of inflammation. Because of it.

What your muscles do when they contract

In 2000, a Danish physiologist named Bente Klarlund Pedersen published research that changed how scientists think about muscle tissue. She had been studying cytokines, small signalling proteins the immune system uses to communicate, and found something unexpected. When muscles contract, they release IL-6. This matters because IL-6 is typically associated with inflammation: elevated resting IL-6 is a marker of active immune response, found in autoimmune flares, infections, and metabolic disease.

But exercise-released IL-6 behaves differently. It arrives in a burst, during movement, in a system that is not under threat. And in that context, it does something almost paradoxical: it suppresses TNF-alpha, one of the main drivers of chronic inflammation, and stimulates IL-10, a powerful anti-inflammatory signal.[1]

Your muscles are not just tissue that moves you through space. They are an endocrine organ. They speak directly to your immune system. And when contracted regularly, they tell it to calm down.

This is the mechanism. The question is whether it holds across conditions where the immune system is already dysregulated and for women specifically, whose hormonal cycles add another layer of complexity to the picture.

Across conditions, what the research shows

The research spans eight conditions, each with its own pathology, its own disease activity patterns, its own relationship to pain and fatigue. But when you look at what exercise does across them, the same direction appears.

The conditions most directly linked to autoimmune signalling, Hashimoto's thyroiditis, rheumatoid arthritis, and lupus, respond to movement through the myokine mechanism described above. In Hashimoto's, a 2019 systematic review found that regular aerobic exercise was associated with reduced anti-thyroid antibody levels in women with the condition, suggesting that exercise-induced IL-6 may dampen the autoimmune signal.[2] In rheumatoid arthritis, meta-analyses consistently show reduced CRP, improved joint function, and no acceleration of joint damage at moderate intensities, including in active disease.[8] Lupus was long considered a contraindication for vigorous movement, due to concerns about triggering flares. A 2020 systematic review found no evidence that moderate exercise triggers flares in stable disease, and documented significant improvements in fatigue and cardiovascular risk in women who trained regularly.[7]

Fibromyalgia moves through a different mechanism: central sensitisation. In fibromyalgia, the nervous system has recalibrated its pain threshold, so that ordinary signals read as pain. Of all conditions on this list, the exercise evidence here is the most robust. A 2017 Cochrane review of 14 trials found that aerobic exercise reduced pain, fatigue, and depression compared to control, with moderate-to-large effect sizes.[6] What movement may be doing is changing how the nervous system processes input, not only suppressing a peripheral inflammatory signal.

For endometriosis, the evidence is earlier but consistent. Women who exercised regularly reported significantly lower pain scores and fatigue in a 2017 controlled study.[3] The proposed mechanism involves prostaglandin regulation and improved estrogen metabolism, two pathways central to the condition's hormonal drivers.

Hypermobile EDS requires a different entry point. Joint instability and proprioceptive deficits mean the standard approach needs to be modified, not abandoned. Low-impact strength training focused on stabilising muscles around hypermobile joints may improve pain, function, and quality of life significantly, with low injury risk when appropriately supervised.[4]

POTS and lymphedema both involve overturning advice that held for decades. In POTS, where the autonomic nervous system fails to maintain blood pressure on standing, the approach is recumbent training: rowing, swimming, recumbent cycling. It builds cardiovascular fitness without triggering the orthostatic response, and many patients see meaningful improvement in standing tolerance over three to six months.[9] For lymphedema, women were told for years to avoid exertion in the affected limb. The 2009 PAL trial ended that recommendation: women who followed a slow-start resistance program showed no increase in lymphedema severity, and many reported improvement in limb symptoms and strength.[5]

What this looks like in practice

Across conditions, the research points to the same pattern: low-to-moderate intensity, consistent movement produces anti-inflammatory benefit. High-intensity training during flares or severe fatigue consistently makes things worse. The threshold between therapeutic and harmful is not fixed it shifts with your condition, your cycle phase, and your current disease activity.

Start below what feels necessary. The most common mistake documented in studies is starting too hard, triggering post-exertional malaise or a flare, and abandoning movement entirely. A start that feels almost too easy is not wasted effort. It is building the base from which you can actually progress.

Your cycle phase matters. Women's inflammatory markers fluctuate with estrogen. In the follicular phase (roughly days 1-14, from menstruation to ovulation), estrogen rises and anti-inflammatory capacity tends to be higher this is often the window where more demanding training is better tolerated. In the luteal phase (roughly days 15-28), progesterone dominates and many women report higher baseline inflammation and fatigue; longer recovery windows may be warranted. During menstruation itself, iron loss and prostaglandin activity may lower tolerance further, particularly for those with heavy cycles or endometriosis.

Pain during movement is not one signal. Muscular discomfort that is temporary and resolves is different from pain that increases during movement or persists for hours afterward. The former is often the expected signal of effort. The latter may mean you have exceeded your current threshold and need to recalibrate not stop entirely, but adjust.

Your body is not fragile. It is asking for something more specific than rest.

Find what applies to you

Select your condition

Each condition has a different entry point, different contraindications, and a different place to start. Select yours to get the research and training starting points that apply to you.

Select a condition above.

Hashimoto's thyroiditis · Autoimmune

Your immune system produces antibodies against your thyroid. Regular movement may reduce that signal.

What the research shows

Aerobic exercise reduces anti-thyroid antibodies

A 2019 systematic review found that regular aerobic exercise was associated with reduced anti-TPO and anti-Tg antibody levels in women with Hashimoto's. Exercise-released IL-6 appears to suppress the autoimmune signalling cycle. Effects were observed with consistent moderate-intensity training over 12 to 16 weeks.

Benvenga S et al., Frontiers in Endocrinology, 2019.

Where to start

Aerobic, consistent, under threshold

20 to 30 min moderate aerobic work 3 times/week (walking, cycling, swimming)
Keep intensity conversational. If you can't hold a sentence, you're above threshold
Track fatigue for 24 hours post-session. Hashimoto's fatigue can lag by a day
In low-energy windows, reduce duration before reducing frequency
Add strength training after 4 to 6 weeks of stable aerobic base

If your TSH is unstable or you are adjusting medication, use perceived exertion as your guide rather than heart rate zones. Thyroid function affects heart rate response.

Rheumatoid Arthritis · Autoimmune joint

Movement at moderate intensity reduces CRP and improves joint function, without accelerating damage.

What the research shows

Consistent evidence across multiple meta-analyses

Meta-analyses consistently show reduced CRP, improved joint function, reduced fatigue, and no acceleration of joint damage at moderate intensities, including during active disease. The concern that movement worsens RA joints has not been supported in controlled trials of moderate exercise.

Multiple meta-analyses; Cochrane reviews of exercise in RA, 2015 to 2022.

Where to start

Dynamic movement over static loading

Swimming and aquatic exercise: low impact, full range of motion
Cycling: cardiovascular load without joint impact
Low-load resistance training focused on range and stability, not maximum weight
During active flares, reduce intensity but maintain frequency if possible
Morning stiffness often improves with light movement rather than more rest

During active flares: reduce intensity sharply but continue some movement if possible. Complete immobilization tends to worsen function. The goal during a flare is maintenance, not progress.

Lupus (SLE) · Autoimmune systemic

Moderate exercise does not trigger flares in stable disease. It significantly reduces fatigue and cardiovascular risk.

What the research shows

No flare risk at moderate intensity in stable disease

A 2020 systematic review found no evidence that moderate exercise triggers flares in women with stable lupus. It documented significant improvements in fatigue, cardiovascular function, and quality of life. Lupus carries elevated cardiovascular risk; exercise is a meaningful preventive intervention.

Bartoloni E et al., Lupus, 2020 systematic review.

Where to start

Start conservative, track for 48 hours

Walking, swimming, and gentle cycling are well-tolerated starting points
Track fatigue and joint symptoms for 48 hours. Lupus flare response can be delayed
Morning or indoor training preferred if photosensitive
Build to 150 min/week moderate activity over 8 to 12 weeks
Return to baseline intensity after active disease or recent flare

If you are on immunosuppressants, infection risk may be elevated during group exercise. This is not a reason to avoid exercise, but a factor in how you structure it.

Fibromyalgia · Central sensitisation

Of all conditions, fibromyalgia has the most robust exercise evidence. Movement may recalibrate the pain threshold itself.

What the research shows

Cochrane review: aerobic exercise reduces pain, fatigue, depression

A 2017 Cochrane review of 14 trials found that aerobic exercise reduced pain, fatigue, and depression compared to control, with moderate-to-large effect sizes. Exercise appears to modulate central pain processing, reducing hypersensitivity rather than acting through peripheral anti-inflammatory pathways.

Bidonde J et al., Cochrane Database of Systematic Reviews, 2017.

Where to start

Pacing is the core skill

Start at 50 to 60% of what you think you can do. Post-exertional malaise is the primary risk
Aquatic exercise (warm water) is particularly well-tolerated and studied
Walking: begin with 10 minutes and add 2 minutes per week
Avoid boom-bust patterns. Doing more on good days leads to crashes
Consistency over weeks matters more than session intensity

Post-exertional malaise can be delayed by 24 to 48 hours. If you felt fine during the session but crashed the next day, that is still a signal to reduce intensity.

Endometriosis · Hormonal / inflammatory

Regular movement reduces pain scores and fatigue, likely through prostaglandin regulation and estrogen metabolism.

What the research shows

Controlled studies show lower pain and fatigue with regular exercise

A 2017 controlled study found that women with endometriosis who exercised regularly reported significantly lower pain scores and fatigue. The proposed mechanisms involve prostaglandin regulation and improved estrogen metabolism, two pathways central to endometriosis progression.

Awad E et al., Journal of Physical Therapy Science, 2017, vol. 29(5).

Where to start

Cycle-phase adjusted training

Follicular phase (post-period to ovulation): higher-tolerance window; build here
Luteal phase: maintain rather than increase; longer recovery windows
During menstruation: reduce intensity based on pain and bleeding severity
Yoga and Pilates have specific evidence for pelvic pain reduction in endometriosis
Avoid high intensity in the 2 to 3 days before expected period onset if you typically experience heavy symptoms

Pain patterns in endometriosis are highly individual. Pain that changes significantly in character during exercise warrants attention.

Hypermobile EDS · Connective tissue

Standard exercise carries joint risk. A stabilisation-focused approach may significantly improve pain, function, and quality of life.

What the research shows

Low-impact strength training focused on stabilising muscles

A 2022 systematic review found that low-impact strength training focused on stabilising muscles around hypermobile joints improved pain, function, and quality of life, with low injury risk when appropriately supervised. Standard high-load programs designed for non-hypermobile people carry joint risk in hEDS.

Palmer S et al., Musculoskeletal Care, 2022, vol. 20(2).

Where to start

Proprioception and stability first

Work with a physiotherapist familiar with hEDS if possible
Proprioception training: balance exercises, single-leg work, controlled range of motion
Avoid end-range loading. Train in mid-range positions where joint stability is maintained
Pilates (reformer) and swimming are commonly well-tolerated
Build slowly: collagen adaptation takes longer in EDS

Hypermobility can make "feeling good" an unreliable indicator of joint stress. Slower progression timelines are specific to this pathology, not overcaution.

POTS · Autonomic dysregulation

Recumbent training bypasses the orthostatic response. Many patients see meaningful improvement in standing tolerance over months.

What the research shows

Recumbent training protocols improve standing tolerance

In POTS, upright exercise triggers the very symptoms it would otherwise help. Recumbent protocols (rowing, swimming, recumbent cycling) allow cardiovascular training without orthostatic stress. Structured recumbent programs lead to meaningful improvement in standing tolerance over three to six months.

Fu Q & Levine BD, Autonomic Neuroscience, 2018.

Where to start

Horizontal first, upright later

Begin fully recumbent: rowing machine, recumbent bike, swimming
Start with 10 to 15 minutes and increase weekly
Salt and fluid loading before sessions may be recommended by your cardiologist
Compression garments during and after exercise reduce pooling
Introduce upright exercise only after several months of recumbent base

Heart rate in POTS is not a reliable training intensity guide — it elevates disproportionately even at low effort. Use perceived exertion (Borg scale) rather than heart rate zones.

Lymphedema · Lymphatic

The old advice to avoid exertion in the affected limb was reversed in 2009. Slow-start resistance training does not worsen lymphedema and may improve it.

What the research shows

The PAL trial ended decades of avoidance advice

The 2009 PAL trial found that women who followed a slow-start resistance program showed no increase in lymphedema severity, and many reported improvement in limb symptoms and strength. Prior to this, women were routinely advised to avoid all exertion in the affected limb. That advice was based on caution, not evidence.

Schmitz KH et al., New England Journal of Medicine, 2009, vol. 361(7).

Where to start

Slow-start resistance, compression during sessions

Wear compression garments during all exercise sessions in the affected limb
Begin with very low weights and higher repetitions (15–20 reps)
Increase load slowly, no more than 10% per week
Aerobic exercise supports lymphatic circulation: walking, swimming, cycling
Monitor the affected limb after each session for swelling changes

If swelling or heaviness in the affected limb persists beyond 24 hours post-exercise, reduce load and consult your lymphedema therapist before progressing. This is an adjustment signal, not a reason to stop.

References

Pedersen BK & Febbraio MA, "Muscles, exercise and obesity: skeletal muscle as a secretory organ," Nature Reviews Endocrinology, 2012, vol. 8, pp. 457-465.
Benvenga S et al., "Exercise and Hashimoto's thyroiditis: association with anti-thyroid antibody levels," Frontiers in Endocrinology, 2019.
Awad E et al., "Effect of aerobic exercise on pain and quality of life in endometriosis," Journal of Physical Therapy Science, 2017, vol. 29(5), pp. 798-802.
Palmer S et al., "Exercise therapy in hypermobile Ehlers-Danlos syndrome: a systematic review," Musculoskeletal Care, 2022, vol. 20(2), pp. 201-214.
Schmitz KH et al., "Weight lifting in women with breast-cancer-related lymphedema," New England Journal of Medicine, 2009, vol. 361(7), pp. 664-673.
Bidonde J et al., "Aerobic exercise training for adults with fibromyalgia," Cochrane Database of Systematic Reviews, 2017, issue 6.
Ayan C et al., "Exercise and lupus: a systematic review," Autoimmunity Reviews, 2020, vol. 19(3), article 102481.
Baillet A et al., "Efficacy of cardiorespiratory aerobic exercise in rheumatoid arthritis," Arthritis Care & Research, 2010, vol. 62(7), pp. 984-992.
Fu Q & Levine BD, "Exercise and non-pharmacological treatment of POTS," Autonomic Neuroscience, 2018, vol. 215, pp. 20-27.