Hot Or Cold Therapy: What’s Better Post Exercise?

For thousands of years, people have known about the benefits of hot cold therapy for treating certain kinds of pain. If you’ve ever applied an ice pack to a throbbing ankle or heat to an ache, you’ll know first-hand about the benefits of hot and cold therapy.

You might have heard about people using hot and cold therapy for muscle recovery after exercise too. But if you’re feeling sore after a run, a game of tennis, squash, handball or some other sport, you might be wondering if this really works. And if so, how?

Let’s learn more about how hot cold therapy works, what it’s used for, and how - and when - to apply cold and heat after exercise.

Why do we get muscle soreness after exercise?

To understand why you would apply cold or heat after exercise, it’s handy to understand why our muscles get sore when we work out in the first place.

Broadly speaking, there are two reasons you might feel soreness or discomfort after exercise:

Delayed onset muscle soreness (DOMS)

DOMS can affect anyone, and they’re especially common when you use muscles you haven’t used so much before - typically when trying a new sort of exercise or when returning to training after a break. DOMS usually begin around 24 hours after you exercise, and can last 2-3 days. While they’re uncomfortable, DOMS aren’t a cause for concern - indeed, they show your body is recovering well.

We don’t entirely understand why DOMS happens, and it’s probably a combination of factors that cause it. But a widely accepted theory is that when you exercise, microscopic tears appear in your muscle fibres. In the hours and days after your exercise, your body will work to repair that damage through a process called inflammation - the area heats up and your body delivers more nutrient rich blood to the muscles. The inflammation makes your muscles feel sore.

Sports injury

A sports injury is a much more serious cause of pain after exercise. While some injuries just require rest - and may benefit from hot cold therapy - you should seek medical advice. If your injury goes untreated, it could get worse and take longer to heal than necessary.

For the rest of this guide, we’re going to focus on using ice or heat after exercise to treat DOMS and general muscle aches. To treat sports injuries, speak to your GP or a physiotherapist. This NHS guide provides advice on using alternating hot and cold therapy for common injuries.

Why use hot cold therapy for muscle soreness?

If you get DOMS after exercise, it usually goes away on its own after a couple of days. So, you might be wondering if it's really worth applying ice and heat packs. The benefit of hot and cold therapy is that it can significantly reduce the severity of the soreness. That means you avoid unnecessary discomfort, and can potentially go back to training again sooner.

There’s plenty of evidence of the benefits of hot and cold therapy for treating sore muscles:

• One study asked two groups of people to do leg squats for 15 minutes. One group was treated with hot and cold wraps, the other got nothing. The group that received hot cold therapy felt less pain and felt much stronger 24 hours later than the other group.
• A different study that was designed to cause DOMS in the lower back found that the group who got hot cold therapy experienced almost 50% less pain than the group that received no treatment.
• Another meta analysis (study of studies) looked at 32 different experiments and found consistent evidence of the benefits of hot and cold therapy for muscle recovery.

Put simply, applying ice or heat after exercise can be part of your strategy for a faster recovery.

Sound body: How exercise affects your body

Cold therapy after exercise - an overview

Using cold packs, cold baths or ice after exercise is a common technique used to reduce pain and inflammation caused by exercise.

Simplifying somewhat, cold therapy works like this:

• If a muscle is feeling sore, then applying an ice pack will make your blood vessels in that area constrict (go narrow), and less blood is carried there.
• This helps to reduce the inflammation and swelling.
• Applying ice, cold packs or using an ice bath also temporarily numbs the area.

There are many different kinds of cold therapy, so the choice is up to you. Options include:

Research suggests there’s no major difference in terms of effectiveness between these different cold therapy techniques - so just do whichever is available or appeals to you.

Cold therapy can be used at any time after you finish exercise, although some research suggests it’s most effective the day after your workout. You could try having a cold bath a few hours after a tiring game or long run, then apply ice packs to target sore muscles every few hours over the next couple of days.

Safety tips for cold therapy after exercise

While applying cold packs or ice after exercise is generally low risk, bear in mind the following safety considerations:

• If you’re using a home-made ice pack, don’t apply it directly to the skin as this can cause ‘ice burns’. Instead, wrap it in a damp towel. For shop-bought ice packs, follow the package instructions.
• Cold therapies should only be used for a short time - around 10-15 minutes, or 20 at most.
• If your skin is especially sensitive to cold, talk to a specialist before applying ice packs.
• Don’t apply ice packs to broken skin.
• If you have a heart condition, poor circulation, or skin conditions, seek medical advice before using cold therapy treatments.

Heat therapy after exercise - an overview

Applying heat after exercise is another well-known way of boosting recovery and dealing with sore muscles.

Using heat supports muscle recovery by having the opposite effect to cold treatments:

Applying heat to a sore area encourages the veins in the muscle to dilate (go wider), which encourages blood to flow to them.

Blood contains oxygen and various nutrients that help the muscle recover faster.

Heat also helps with reducing stiffness by warming your muscles up.

As with cold therapy, there are several ways to apply heat after exercise:

• Hot bath: Having a hot bath is perhaps the simplest way of applying heat to sore muscles that you can do at home.
• Sauna: Many gyms have a sauna where you can ‘sweat out’.
• Hot water bottles or wheat packs: Low cost and effective, hot water bottles and microwavable wheat packs (that are wrapped in towelling) allow you to apply a source of heat to the skin.
• Heat creams, sprays and gels: Follow the instructions on the pack, and apply these ointments directly to sore areas.
• Electric heat pads: These usually plug into the wall and provide a source of heat that you can wrap around or place under sore muscles.

These methods all work slightly differently, but they all provide the same benefits.

As with cold therapy, heat therapy can be applied any time after a workout, although it seems to be most effective immediately after exercise. You could apply a heat pack to sore muscles soon after a tough game or hard run. Then head to the sauna the next day to ‘loosen up’ stiff joints, for example.

Safety tips for heat therapy after exercise

Using heat after exercise is generally safe, but you should take some precautions to avoid burns and other issues:

• If you’re using a ‘home made’ method (such as a hot water bottle), don’t use boiling water, and don’t apply the heat source directly to the skin. Instead, wrap it in a towel or another material to avoid burns.
• Don’t go to sleep while using any heat treatment.
• Use heat treatments for short periods - 10-15 minutes is more than enough.
• Don’t apply heat to damaged skin.
• If you’re pregnant, have a heart condition, have very sensitive skin or other conditions, get medical advice before using heat treatments.

Alternating hot and cold therapy

There are many benefits of hot and cold therapy, and the good news is that they can also be used in combination. If you’re experiencing DOMS and other aches and pains from overuse, then alternating hot and cold therapy means you get the benefits of both.

You might want to start by applying heat to sore muscles first. This warms the area up, encourages blood to flow to the ache, and helps to reduce stiffness. After 10-15 minutes, you could then apply cold to the area. This helps to numb the soreness, and makes blood vessels narrower to reduce inflammation in the affected area. Over the course of a day or two, you could try alternating between hot and cold therapy in this way and get the benefits of both treatments.

Should you use cold or heat before or after exercise?

Hot cold therapy is mainly intended to treat DOMS, minor injuries and aches after you’ve finished exercising.

That said, if you already have sore muscles, you might want to consider applying heat before your next exercise session. This could help loosen up tight muscles, and would encourage blood to flow to the area - in a similar way to a warm up before exercise (you should still do a proper full body warm up before training too).

On the other hand, using ice before exercise wouldn’t be beneficial. Since applying cold causes your veins to constrict, that would mean less blood gets to your muscles - which is exactly where it’s needed when you’re exercising.

Practical recommendations for hot cold therapy

If you’ve never tried using hot cold therapy for treating muscle soreness or minor injuries, here are some more tips to get the most out of it:

• Know the limits: There are many benefits of hot cold therapy, but it has its limits too. If you’re experiencing pain more than three days after exercising, then that might suggest you have a sports injury. You’ll need to rest, and seek medical advice.
• Won’t fix serious injuries or syndromes: Similarly, hot cold therapy won’t treat more serious injuries such as sprain, plantar fasciitis, tennis elbow or similar sports injuries. Depending on the injury, you’ll need to rest, and could also benefit from visiting a physiotherapist or sports instructor for advice on proper form and exercises.
• Start slow and low: If you’ve never used hot cold therapy before, start ‘slow and low’. For example, the first time you use an ice bath, you don’t need to spend a full 20 minutes in there - begin with a shorter session and build up as you get more experience. The same goes with heat treatments - use them in limited areas for lower amounts of time, until you know what you’re comfortable with.

Strength: Building muscle can help reduce your risk of sports injury

The right sportswear can also help avoid injuries

If you notice you regularly feel aches and pain after exercise, it’s also worth looking at your footwear. Shoes with the wrong kinds of support, that don’t have enough cushioning, or where the grip has worn away, can all contribute to overuse injuries. At ASICS, we’ve designed world-class footwear for popular sports that helps cushion, support and protect your feet, muscles and joints. Browse our shoes for different sports.

Similarly, compression leggings for women and men can help reduce potential muscle soreness too.

Part of your recovery plan

Using ice or heat after exercise can play a very helpful role in your recovery - particularly from intense activity. Not only does hot cold therapy reduce feelings of pain and soreness, it also means you’ll feel less stiff, and lets you get more enjoyment out of your sport. And that can mean you’re ready to go again sooner.