Swimming is one of the best exercises you can do for arthritis. Water supports your body weight, taking pressure off painful joints while still letting you build strength and improve flexibility. For people with knee, hip, or shoulder arthritis who find walking or running uncomfortable, moving to the pool can be the difference between staying active and giving up on exercise entirely.
Why Water Works for Arthritic Joints
The core advantage of exercising in water comes down to buoyancy. When you’re submerged to your chest, water supports roughly 80% of your body weight. That dramatically reduces the load on weight-bearing joints like knees and hips, protecting against further joint degradation while still allowing meaningful movement.
But buoyancy is only part of the picture. Water pushes back against you in every direction, so even slow movements require more muscle effort than the same motion on land. This builds strength around joints without the jarring impact of weights or resistance machines. The hydrostatic pressure of water also promotes blood circulation, eases soft-tissue tightness, and can relieve muscle spasms and fatigue. And because water provides natural resistance, you can get the same cardiovascular benefit at a lower exercise intensity than you’d need on land.
Swimming vs. Land-Based Exercise
Land-based exercise like walking, cycling, and strength training remains a core recommendation for managing arthritis. It improves muscle strength, relieves pain, reduces stiffness, and helps with physical function. The catch is that too much weight-bearing exercise can worsen symptoms by increasing the load on already damaged joints.
Researchers have tried to determine whether aquatic exercise outperforms land-based exercise for knee osteoarthritis specifically. A meta-analysis of eight randomized controlled trials involving 579 patients found that both approaches produced real benefits, but consistent conclusions about which is superior haven’t been reached. The practical takeaway: aquatic exercise is at least as effective as land-based exercise for pain and function, with less risk of aggravating your joints. For people who struggle with weight-bearing activity, that makes it the better choice. For those who tolerate land exercise well, a mix of both likely offers the most benefit.
Lap Swimming vs. Water Aerobics
You don’t have to swim laps to benefit. Water aerobics classes, walking in the pool, and simple range-of-motion exercises in shallow water all count as aquatic exercise and can be easier to start with if you’re not a confident swimmer or if your joint mobility is limited.
Lap swimming offers a more intense cardiovascular workout and engages a wider range of muscle groups. Freestyle (front crawl) and backstroke are generally the most joint-friendly strokes because they use smooth, rhythmic motions without sudden twisting. Water aerobics, on the other hand, lets you target specific joints with controlled movements and is often done in a group setting with an instructor who can suggest modifications. Many people with arthritis start with water walking or a class and progress to laps as their strength and confidence grow.
Strokes to Be Careful With
Not all swimming strokes are equally kind to arthritic joints. Breaststroke is the main one to watch. Its signature whip-kick motion forces the knee into a stressed, rotational position that can strain the ligament on the inner side of the knee. If you have knee arthritis, this repeated twisting can increase pain and inflammation rather than relieve it.
Butterfly stroke places significant demands on the shoulders and lower back, making it a poor fit for arthritis in those areas. If you want to swim laps, freestyle and backstroke are your safest options. Keep your strokes smooth and avoid pushing through sharp pain. A few sessions with a swim coach who understands joint limitations can help you refine your technique so you’re protecting your joints rather than punishing them.
How Often and How Long
Most research on aquatic exercise for arthritis used sessions of about one hour, performed two or three times per week. That’s a reasonable target, but you don’t need to start there. If you haven’t been active, begin with 15 to 20 minutes in the pool and gradually add time as your joints adapt. Consistency matters more than duration. Three 30-minute sessions per week will do more for your joints over time than one exhausting 90-minute swim.
Pay attention to how your joints feel in the hours after your swim, not just during it. Some mild stiffness is normal as you begin a new routine, but increased swelling or pain that lasts into the next day is a sign you’ve done too much. Scale back your time or intensity and build up more slowly.
Getting the Temperature Right
Water temperature makes a real difference for arthritic joints. Pool temperatures between 83 and 88°F (roughly 28 to 31°C) are generally the most comfortable range for exercise. Water in this range warms stiff joints and muscles without overheating you during activity.
Most recreational pools sit around 78 to 82°F, which can feel cold at first but is fine once you start moving. Therapeutic pools and many pools used for arthritis programs keep temperatures at the warmer end of the range. If cold water makes your joints seize up, look for a warm-water therapy pool at a local hospital, rehabilitation center, or YMCA. Heated pools are especially helpful for morning sessions when joint stiffness tends to be at its worst.
Practical Tips for Starting
- Use the pool entry that works for you. Steps with a handrail are safer than ladders. Many therapy pools have zero-depth entries or ramps.
- Wear water shoes. Pool decks and pool floors can be slippery, and water shoes give you traction while also cushioning your feet.
- Try a kickboard or pool noodle. These let you focus on lower-body movement without worrying about staying afloat, reducing strain on shoulders and arms.
- Stretch gently in the water before you start. The warmth and buoyancy make it easier to loosen up than stretching on land.
- Don’t skip days between sessions at first. Recovery between workouts matters, especially when your joints are adjusting to a new routine. Alternating days gives your body time to respond.
Chlorine can dry out skin, which is worth noting if you also deal with psoriatic arthritis or sensitive skin. Rinse off immediately after your session and apply moisturizer while your skin is still damp.