How does hydrotherapy help recovery?

Hydrotherapy — also known as aquatic physiotherapy — is an evidence-based approach to rehabilitation conducted in a heated pool under the supervision of a qualified physiotherapist. If you have heard the term and wondered how warm water could form part of a physiotherapy programme, this article explains what hydrotherapy involves, the properties of water that support rehabilitation, and the conditions where it is commonly used.

What does hydrotherapy involve?

Hydrotherapy sessions take place in a purpose-built heated pool, typically maintained between 33°C and 36°C — warmer than a standard swimming pool. A physiotherapist designs and supervises a programme of exercises and movements suited to your individual presentation. Sessions may involve walking in waist-deep water, range-of-motion exercises, strengthening movements against water resistance, or balance and coordination activities.

Unlike general pool exercise, physiotherapist-led hydrotherapy is a clinical service. Your physiotherapist will first assess your condition on land, then develop an aquatic programme that complements your overall treatment plan. Session length and content are adjusted based on your progress and response.

The buoyant force of water can reduce your functional body weight by approximately 50 per cent at waist depth.

How warm water may support rehab

Three physical properties of water create conditions that may be beneficial for rehabilitation: buoyancy, warmth, and resistance.

Buoyancy reduces the effective weight load on joints and soft tissues. When standing at waist depth in water, the buoyant force reduces your functional body weight by approximately 50 per cent. This may allow movement that is not yet comfortable on land — for example, walking with less load through a healing knee or hip.

Warmth from the heated pool may contribute to muscle relaxation and increased ease of movement for some people. The clinical relevance of water temperature varies by individual and condition.

Resistance from water provides a medium for graduated strengthening. Unlike free weights or resistance bands, water resistance increases proportionally with movement speed, which may allow exercise intensity to be modulated naturally during the session.

Conditions where hydrotherapy is commonly used

Hydrotherapy is used across a broad range of musculoskeletal and neurological conditions. Presentations where it is commonly included as part of a physiotherapy programme include:

• Post-surgical rehabilitation — for example, after total knee or hip replacement, where reduced joint loading may allow early movement during the recovery period
• Arthritis — both osteoarthritis and rheumatoid arthritis presentations where land-based exercise is not well tolerated
• Chronic pain — where gentle, supervised movement in a supportive environment may be more accessible than land-based exercise
• Neurological conditions — such as multiple sclerosis, acquired brain injury, or stroke, where water may support balance and movement quality
• Spinal conditions — including back pain and disc-related presentations where load reduction may allow more movement

Whether hydrotherapy is appropriate for your specific condition depends on a thorough physiotherapy assessment. Not every presentation benefits from an aquatic approach.

What to expect in a session

Before your first session, your physiotherapist will assess you on land to understand your movement patterns, strength, range of motion, and any precautions relevant to aquatic exercise. They will explain the session structure and what to bring (swimwear, a towel, and footwear suitable for pool surrounds).

In the pool, your physiotherapist will guide you through the programme, observing your movement and adjusting exercises as needed. Sessions typically run between 30 and 45 minutes. Many people find the first session is gentler than expected — the aim is to assess how your body responds to the aquatic environment before progressing intensity.

Who may benefit?

Hydrotherapy may be considered for people who find land-based exercise difficult due to pain, weakness, or load sensitivity; those recovering from surgery or a significant injury; people with progressive neurological conditions; and older adults where gentle, supervised movement in a warm-water environment may be more accessible. Your physiotherapist will discuss whether hydrotherapy may be appropriate for your situation during your assessment.