This is because salt can lower the freezing point of the ice and this causes the ice to stay colder for longer. Ice can be left on for 20-30 minutes but there is little benefit to be gained by leaving it on for longer. You run the risk of damaging the skin if ice is left on the skin for more than 20-30 minutes at a time. Leaving the ice on for too long can also slow down the healing process. Perhaps this is the simplest one if you don’t have any of the materials mentioned above. All you need is a sponge, any size of your choice. You can make use of what you’ve got lying around the house. A plastic water bottle or even a plastic milk jug will work.

The pain experienced in the 12-48 hrs following over-exertion is due to many very small injuries to the muscle fibres or to the tendons that attach the muscles to the bones. Blood rushing to the area causes inflammation, redness and tenderness, therefore cold is used to reduce blood circulation. After a hard work out Ice (also known as cold therapy or cryotheraphy) constricts the blood vessels, which slows down blood flow to injured or painful areas. This helps to reduce swelling, redness, inflammation and although often uncomfortable at first, it can also numb pain. When to apply cold/ice: New injuries

Have a magnesium bath

Electric cool boxes Don’t require ice but they do require power. You either plug the box into your car (12V), the most common type of charger, or into the mains by a UK plug. They require constant power, though will still keep contents cool for a few hours if you unplug. You can get battery-powered boxes, but they’re less common and far more expensive.

The UK government have been advised by the environmental think-tank ‘WRAP’ to set a target of 75% PET bottles recycled by 2025 – a number far more tenable if we all switch to using this type of plastic as opposed to non-recyclable alternatives. Our tests showed some key differences between these two products that are worth considering before buying: The Food Standards Agency recommends you keep your fridge set at 5°C, so that cold food stays at around 8°C. You'll want to keep your bag below 5°C, especially if you have perishables, for as long as you want to keep eating and drinking stuff from the bag. The heat should be warm, not excessive. Don’t apply heat for longer than 20 minutes and protect your skin from burns or scalds by wrapping a thin towel around any heat source. Also never use a heating cream along with a heating pad or wrap. Rub the pain away All the cool bags we tested so far perform decently, but the best ones keep water cool all day, whereas in the worst, the water is closer to room temperature by the end. Leakproof

Gout

They are generally very efficient at their job, and understanding which is the best one to use for particular pains and aches can help you ease soreness, stiffness, swelling and inflammation faster, as well as prevent them from getting worse. To replicate getting bits in and out of the bag, we opened and closed it at regular intervals throughout the test.

In one study, some people who used ice said that it was helpful for managing pain, although this did not translate into a lower use of painkillers. Many people find that ice is helpful when used to manage pain in the short term. It is unlikely that it will have much of a negative effect in the long term when used in this way.

When freezing water turns into ice, it will expand by as much as 9% in volume, with nothing and no one able to stop it!

While none of the cool boxes leaked when upright, all but one leaked from the lid if tipped over onto their side. It's worth making sure your cool box isn't going to fall over easily when being transported. Comfort Ice is most commonly used to treat new injuries, within the first 48 hours. It helps to control the inflammatory response, which reduces swelling and pain, as well as bruising. Ice is ideal for injuries such as sprains and strains. Pain due to over-exertionThe best cool boxes have features that improve portability, such as wheels and extendable handles. The worst have uncomfortable handles and are heavy to carry. Durability Also, don’t apply it directly to the skin. Use a cloth barrier to protect your skin from damage such as frostbite. When should ice not be used? Size You'll generally find that cool boxes have larger capacities. You can get cool bags up to 50 litres, but if you need more consider a cool box instead. To replicate getting bits in and out of the bag, we open and close it at regular intervals throughout the test.