As the UK endures a heatwave, joint preservation specialist Professor Paul Lee is highlighting a hidden danger: dehydration's damaging effect on joints and cartilage. Cartilage is approximately 70% to 80% water, making hydration essential for its function.
Cartilage Needs Water to Function
Unlike other tissues, cartilage lacks a direct blood supply and relies on fluid movement within the joint for nutrients. Dehydration disrupts this process. Professor Lee explained: 'Cartilage behaves a little like a sponge. It needs hydration and movement to help nutrients circulate through the joint. If the body is dehydrated, the environment the cartilage depends on becomes less favourable.'
The 'Rule of Six' for Hydration
To help people stay hydrated, Professor Lee recommends the 'rule of six':
- Do not go more than six hours without drinking water during the day
- Do not go more than six hours without passing urine while awake
- If your urine is darker than a pale straw colour, increase your fluid intake
- Drink more if you are sweating heavily
- Avoid excessive alcohol consumption during hot weather
- Seek medical advice if you become dizzy, confused or stop passing urine normally
Professor Lee said: 'I often tell patients to protect their cartilage with the 6x6 rule. Stay hydrated enough to pass pale urine at least every six hours. It's a simple way to monitor whether your body is getting enough fluid.'
Who Is Most at Risk?
The guidance is especially crucial for older people, those with arthritis, and anyone spending long periods outdoors. While hydration alone won't prevent joint issues, it supports the body's natural processes. Professor Lee added: 'We often focus on exercise, treatments and medications, but basic hydration is one of the foundations of healthy joints. During a heatwave, people should not wait until they feel thirsty. By then, dehydration may already be affecting how the body functions.'
