Warm water does something for a painful body that a gym floor cannot. It carries much of your weight, so movement that hurts on land often becomes possible again — and the programme becomes one you can keep doing. Our aquatherapy pool, Rajasthan's first purpose-built therapy pool, is used for exactly that. Here is what the published evidence says aquatic therapy achieves, and who gains most from it.
Why movement is easier in water
Four properties of water do the work, and each of them has been measured.
Buoyancy takes the load off your joints
Stand in water up to your waist and roughly 40 to 56 per cent of your body weight still passes through your legs. Stand in chest-deep water and it drops to about 25 to 37 per cent — the water is carrying around two thirds of you, and deeper still — up to the shoulders — it takes as much as 80 per cent of your weight off your legs. Those are the classic Harrison and Bulstrode figures, reproduced and re-measured in a 2014 study of 193 adults in BMC Musculoskeletal Disorders, which recorded 52 per cent at waist depth. For a knee that objects to every step on land, that is the difference between practising walking and not practising at all.
Warm water loosens what is stiff
Professional guidance sets a therapeutic range of 32 to 35.5°C, with 34 to 35°C preferred for painful and arthritic joints (ATACP, 2021). Warmth makes joints easier to move through range and muscles more willing to let go. Where heat sensitivity is part of the condition — it affects 60 to 80 per cent of people with multiple sclerosis — thermoneutral water is used instead. Temperature is part of the prescription, not an afterthought.
Water pressure supports you from every side
Pressure rises with depth, by about 74 mmHg for every metre, and presses evenly all around the immersed body. Support comes from every direction at once, rather than from a stick or a rail you have to hold. Immersion also moves around 700 mL of blood towards the chest within seconds, which is why time in the pool is real physiological work even when it feels gentle — and why sessions are supervised throughout.
Resistance that matches your effort
Water is roughly 800 times denser than air and drag rises steeply with speed, so it pushes back harder the harder you push, and eases off the moment you do. There are no weights to load, nothing to drop and no impact to absorb. When this was measured directly on an aquatic treadmill, oxygen consumption nearly doubled — from 11.4 to 22.2 mL per kg per minute — at a constant slow walking pace of about one metre per second, purely by increasing the water resistance (Bressel, 2012). For someone who cannot walk quickly on land, that is a way to get genuine cardiovascular work at a pace they can manage.
What the evidence shows it helps
Knee and hip osteoarthritis
This is the strongest evidence base aquatic therapy has. The Cochrane review (2016) pooled 13 randomised trials and 1,190 people with osteoarthritis of the knee or hip: pain improved, disability improved and quality of life improved, on moderate-quality evidence, with no serious adverse events in any trial. Cochrane judged the improvements clinically relevant.
The largest and most recent synthesis is bigger again — 22 trials, 1,394 participants (Xu, 2023). It found moderate improvements in pain (standardised mean difference −0.58) and stiffness (−0.57), a smaller one in physical function (−0.35), and the pain benefit was still measurable three months after the programme finished. Again, no serious adverse events.
Set head to head against the same work on land, the result is a tie — aquatic exercise is as effective as land-based exercise for pain, stiffness and function, and, as you will see below, a good deal easier for many people to keep doing. The international OARSI guideline conditionally recommends aquatic exercise for knee osteoarthritis.
Fibromyalgia
Cochrane again (2014; 16 trials, 881 participants). Against no exercise, aquatic training improved pain by about 6.6 points on a 0 to 100 scale, with gains in stiffness, physical function and overall wellbeing, and fitness improved by 37 metres on the six-minute walk test. Here too, water matches land-based exercise for pain, stiffness and function — with the comfort advantage on the water's side.
Parkinson's disease
This is the one place where the evidence puts water ahead. A 2019 review in the Journal of Physiotherapy compared aquatic therapy directly with land-based exercise and found slightly to moderately greater benefit in the water: 2.7 points better on the Berg Balance Scale, 4 points better on the Falls Efficacy Scale (less fear of falling) and 6 points better on the PDQ-39 quality-of-life questionnaire. The balance advantage was still present at follow-up. It is a small evidence base — 7 trials and 159 participants — but it points consistently in the same direction.
Multiple sclerosis
A 2026 review of 7 randomised trials and 347 participants found aquatic exercise improved fatigue (standardised mean difference −1.20), mobility and function (0.70) and quality of life (0.45). Fatigue is often the symptom people most want addressed, and thermoneutral water is what makes exercise workable when heat is a trigger.
Chronic low back pain
A 2022 review of 13 trials found aquatic exercise better than no therapy for pain, and comparable to land-based exercise for disability. If back pain has kept you out of exercise altogether, a pool is a sensible place to start moving again.
After orthopaedic surgery
This is one of the most practical findings in the whole literature, and one of the most reassuring. Across 8 controlled trials, aquatic therapy started within three months of orthopaedic surgery improved everyday activities and was as effective as land-based therapy for pain, swelling, strength and range of movement — with no increase in wound-related problems. Professional guidance is just as direct: "well managed hydrotherapy pools pose no increased risk of wound infection at any stage of healing" (ATACP, 2021), with the surgical dressing covered by a waterproof one before you go in.
Aquatic work after stroke is covered separately in our stroke rehabilitation article.
The programme people actually keep doing
Exercise only helps if it gets done, and this is where water offers something land does not.
In a randomised trial comparing the two in knee osteoarthritis, 44 per cent of the land-based group reported discomfort from their exercise, against 11 per cent of the pool group. Three people left the land programme because of increased pain; nobody left the water programme for that reason. Compliance was 92 per cent in the pool and 85 per cent on land (Lund, 2008). A 2018 review of aquatic versus land-based exercise in osteoarthritis found the same pattern — equal results, higher adherence, higher satisfaction in the water. In pregnancy, adherence to aquatic programmes has averaged 94.5 per cent.
That is the honest case for a pool. For most conditions it delivers what the same work delivers on land, and it is markedly easier for a sore body to stay with.
Who should have a word with us first
Most people can simply come and start, and a first visit is normally an assessment where what belongs in the water and what belongs on land is worked out with you. Please leave at least 48 hours after any diarrhoea or vomiting has settled, and stay out of the pool while you have a fever. And if you have a heart condition, epilepsy or diabetes that is not yet well controlled, tell the team before your first session so we can check what is safe and plan around it.
Where to go from here
If any of this sounds like your situation, our aquatherapy page explains how the pool is used here in Jaipur alongside land-based rehabilitation, so the two support each other. When you would like to talk it through with someone, the contact page is the place to start.
This article is general information, not a diagnosis or a treatment plan. Please discuss your own situation with your doctor or physiotherapist.