Written by the Nuvirox Research Team
Key Points
- A Cochrane review of 13 randomized trials found aquatic exercise gives small, short-term improvements in pain and function for knee and hip osteoarthritis.
- At least one head-to-head trial found land-based exercise produced a longer-lasting pain reduction than aquatic exercise at 3-month follow-up.
- Water's main advantage seems to be comfort and buoyancy for people who can't tolerate land-based exercise yet — not a bigger effect size.
Short answer: yes, modestly, especially as a comfortable starting point — but it isn't clearly superior to land-based exercise. Aquatic exercise (swimming, water aerobics, pool-based strengthening) reduces pain and improves function for people with knee or hip osteoarthritis in randomized trials, largely because buoyancy takes load off the joint while still allowing movement and muscle work. But when researchers have compared water workouts head-to-head against equivalent land-based programs, land-based exercise has sometimes come out ahead on durability of the pain benefit.
Why would being in water help an arthritic joint?
Water reduces the effective load on weight-bearing joints — standing in chest-deep water offloads a substantial percentage of body weight — while warm water (typically kept between 32–36°C in trial protocols) is thought to ease muscle tension and reduce pain sensitivity. That combination lets people move through a fuller range of motion with less pain than the same movement would cause on land, which may make it easier to build the habit of regular exercise in the first place.
What the Cochrane review found
The Cochrane Collaboration's review of aquatic exercise for hip and knee osteoarthritis pooled 13 randomized controlled trials involving 1,190 participants comparing aquatic exercise to a control condition (usual care, no exercise, or education). It found small-to-moderate short-term improvements in pain and self-reported function, with less clear evidence for medium- and long-term benefit or for improvements in objective physical function measures. The review authors characterized the quality of evidence as generally low to moderate, reflecting variation in trial design and program intensity.
Study snapshot: Aquatic vs. land-based exercise (Silva et al., Phys Ther, 2008)
| Design | RCT, hydrotherapy vs. land-based conventional exercise |
| Population | Adults with knee osteoarthritis |
| Finding at 8 weeks | No clear difference between groups immediately after the program |
| Finding at 3 months | Pain reduction favored the land-based group; aquatic group did not show the same durability |
The honest counterweight
A broader meta-analysis of aquatic exercise for lower-limb osteoarthritis similarly found that while aquatic exercise clearly beat no-exercise controls, head-to-head comparisons with land-based programs generally showed the two approaches converging on similar outcomes rather than water pulling ahead — and, in the trial above, actually falling behind on durability. This is the finding that keeps swimming from being an obvious "better" choice over land exercise:
At least one randomized trial directly comparing aquatic and land-based programs found no difference immediately after the 8-week program, but a meaningful pain reduction favoring land-based exercise at the 3-month follow-up that the aquatic group didn't match. Other reviews and meta-analyses have found aquatic exercise roughly comparable to land-based exercise rather than superior to it. The practical read: water isn't a stronger intervention, it's a more accessible one for certain people and certain stages of pain.
What about swimming laps specifically, versus water aerobics?
It's worth being precise about what was actually tested. Most of the randomized trials behind the Cochrane review used structured aquatic exercise classes — walking against water resistance, gentle range-of-motion drills, and light strengthening moves in chest-deep water — rather than continuous lap swimming with strokes like freestyle or breaststroke. Some strokes, particularly breaststroke's whip kick, can load the knee in ways that feel uncomfortable for people with significant knee osteoarthritis. If lap swimming aggravates your knees, a shallow-water exercise class is a better-supported starting point than pushing through laps.
What swimming won't do
It won't reverse structural joint damage, and the evidence doesn't support it as a faster or more powerful fix than land-based strengthening. If getting into a pool isn't accessible, that's not a reason to skip exercise altogether — land-based options have equivalent or better long-term data. New joint swelling, warmth, or pain that limits weight-bearing should be checked by a doctor before starting any new exercise program.
How to actually start
Trial protocols generally used sessions of 30 to 60 minutes, 2 to 3 times weekly, combining walking, gentle range-of-motion work, and light resistance in chest-deep warm water. Community pools with dedicated arthritis or aquatic therapy classes typically follow a similar structure, and many are run by physical therapists or certified aquatic fitness instructors familiar with modifying movements around joint pain. Building up gradually over 4 to 6 weeks, rather than starting at full trial-level intensity, is a reasonable way to gauge how your joints tolerate the new load. If water access is limited, our piece on yoga for joint pain covers a land-based, low-impact alternative with its own trial evidence, and our existing guide on exercise and arthritic joints covers the broader land-based picture.
Is swimming better than water aerobics for arthritis?
Trials have generally tested structured aquatic exercise programs (walking, resistance, range-of-motion work) rather than lap swimming specifically, so the evidence speaks more directly to water aerobics-style classes than to swimming laps.
How warm does the pool need to be to get the benefit?
Trial protocols typically used water heated to 32–36°C (about 90–97°F), which is warmer than a standard lap pool and closer to a therapy pool.
Can aquatic exercise replace my strength training on land?
It can be a reasonable substitute during flare-ups or for people who can't tolerate land-based loading, but given the durability findings favoring land-based exercise, transitioning back to some land-based strengthening as tolerated may be worth discussing with a physical therapist.
Is it safe to start aquatic exercise with a recently replaced joint?
Timing after joint replacement surgery depends on wound healing and surgeon clearance; check with your surgeon or physical therapist before returning to pool-based exercise post-surgery.
Why did land-based exercise hold up better in the long-term comparison?
The trial that found this didn't establish a clear mechanism, but one plausible explanation is that land-based strengthening builds more of the muscular support structures joints rely on day-to-day, since daily life mostly happens outside a pool.
From Nuvirox
Why we formulated Joint+ Restore
Joint+ Restore is our joint-support formula, built around ingredients studied for cartilage, comfort, and mobility support as part of a broader approach to joint health. Our formula is currently being updated, so we're not listing specific ingredient amounts here — but the goal stays the same: a joint-support supplement worth taking consistently. It's backed by our 60-day money-back guarantee, long enough to actually judge whether it's doing anything for you.
Learn more about Joint+ Restore →The bottom line: Aquatic exercise reliably reduces pain and improves function for arthritic knees and hips in randomized trials, and it's a genuinely gentler entry point for people who struggle with land-based movement. But it isn't a stronger treatment than land-based exercise — at least one careful comparison found land-based programs held onto their pain benefit better over time. Use water as a starting point or a flare-up-friendly option, not necessarily the finish line.
References
- Bartels EM, Juhl CB, Christensen R, et al. Aquatic exercise for the treatment of knee and hip osteoarthritis. Cochrane Database Syst Rev. 2016;3:CD005523. PMID: 27007113.
- Silva LE, Valim V, Pessanha AP, et al. Hydrotherapy versus conventional land-based exercise for the management of patients with osteoarthritis of the knee: a randomized clinical trial. Phys Ther. 2008;88(1):12-21. PMID: 17986497.
- Waller B, Ogonowska-Slodownik A, Vitor M, et al. A randomised controlled trial of aquatic and land-based exercise in patients with knee osteoarthritis. PMID: 18509579.
- Moseng T, Vliet Vlieland TPM, Battista S, et al. EULAR recommendations for the non-pharmacological core management of hip and knee osteoarthritis: 2023 update. Ann Rheum Dis. 2024;83(6):730-740. PMID: 38212040.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.