There are many forms of heat and cold therapy, and many different, and sometimes conflicting prescriptions for when to use each. So how do you sort through the myriad of information and application methodologies to determine which is best for your particular need? Or does the application of heat and / or cold really matter at all? Is it just snake oil, or is there science backing the application of hot and cold to our bodies?
Let’s start by forgetting about the methods, whether sauna or ice bath, what’s going on inside of us when you apply a temperature variation to your body? The short answer is a variation in blood flow. Cold causes your blood vessels and arteries to narrow, decreasing the flow of blood to the area of the body you’re applying it to. Heat on the other hand causes these same blood carriers to dilate, increasing the flow of blood. This change in blood flow causes a variety of side effects.
Let’s Start With Cold
Swelling and its related pain are both caused by the bodies response to injury. Injury is a very loose term here, it can refer to an actual perceived injury – such as a twisted ankle, or micro injuries – such as micro-tears of muscles from a workout. The body responds to these injuries by increasing blood flow to provide oxygen and white blood cells to the affected areas. This increased blood flow, while providing the needed elements to heal, also causes inflammation (swelling). The swelling serves to help stabilize a joint injury for example, but it also causes pain. There’s only so much room inside your body, adding fluids to an area may help to stabilize it, but the resultant pressure also causes pain.
By applying cold to an area, we can cause the blood vessels and arteries to constrict, thereby slowing down the flow of fluids into the area, which can reduce swelling, and also pain. This reduction of blood in the area also causes numbness which acts in addition to the relief of pressure to minimize pain messages sent to the brain.
Cold therapy is most beneficial within the first 48 hours after an injury, and is most likely the treatment you should be using to treat an injury shortly after it’s occurred. The exception to this is if you’re already cold, if there is an open wound, or there is a risk of cramping. Also, cold therapies should rarely be used for back pain.
It’s Getting Hot In Here
Not surprisingly, heat causes the opposite physiological response in the body than cold therapy. Heat causes blood vessels and arteries to dilate, growing wider and allowing for increased blood flow to an area and lowering blood pressure. This increased blood flow can help to flush out the lactic acid caused by exerting a muscle. Lactic acid is the main cause for muscle soreness, so the application of heat can help ease this particular type of pain. Heat therapy is a good option for relieving pain or spasms in the neck and back and an effective therapy when preparing for activity.
What causes lactic acid? When exercising, your body needs a lot of energy. To create this energy, it burns blood sugar, but if the amount of oxygen you breathe can’t keep up with the burning of sugars, some of the sugars are burned without oxygen (anaerobic respiration). A side effect of anaerobic respiration is lactic acid.
Similar to cold therapy, heat should not be applied to an open wound, if skin is hot red or inflamed, suffering from dermatitis or if the area is numb. Always avoid high heat and check with a doctor if you have high blood pressure or heart disease before using heat therapies.
How Can You Make Best Use Of These Therapies?
There are a few basic guidelines to getting the most out of cold and heat therapies, some overlap, others are exclusive to one or the other therpay type:
- Both cold and heat therapies should be limited to 20 minute intervals every 4-6 hours.
- Cold therapy is most effective when applied during the first 48 hours.
- NEVER apply ice directly to the skin, wrap ice packs in a soft cloth first to avoid frostbite. The one exception to this is ice massage, because the ice is moving constantly the chances of damaging your skin is decreased.
- Avoid using heat therapies on a new injury.
Next let’s take a look at 5 different ways of applying these therapies.
Cold Showers
Probably one of the easiest ways of applying cold therapy, cold showers claim a lot of supposed benefits, including: increasing alertness, improving immunity and circulation, relieving depression and stimulating weight loss. Without turning this into a college thesis on cold therapy, we’ll stay concerned with what we’ve already covered, and the science we know to be true. Cold showers are a quick and easy way to lower your body temperature. Although they’re not the most pleasant thing to add to your life at first, once you’ve become accustomed to them, they’re not that bad.
A cold shower is just that, a COLD shower (50-59 degrees F). Not a cool shower, or a lukewarm shower, but cold. That doesn’t mean you have to start with straight out of the tap cold water, you can ease yourself in, working your way colder and colder, but eventually (if not right away) you want to eliminate the hot water completely.
What you should expect other than cold water is an increase in your breathing, very short quick breaths, almost gasping. The experience is very similar to jumping into a cold pool and it’s caused by something called the mammalian dive reflex. This is the body’s response to what it perceives as a large loss of body heat very quickly. Try to slow and control your breathing, once your brain realizes that you’re not in any immanent danger, your breathing will return to normal, and your body will acclimate itself to the experience by increasing your circulation to warm your blood in your inner core and recirculate it to the cooler parts of your body. Eventually the water won’t feel so cold, and a cold shower can feel pleasant – again, similar to a cold pool once you’ve gotten used to it.
They start out with an unpleasant beginning, but ultimately a cold shower will help your muscles to recover from a tough workout as we covered earlier.
Hot Baths / Hot Tubs / Hot Showers
Maybe the opposite of a cold shower is it’s much more pleasant cousin, the hot bath, hot tub soak or hot shower. As we discussed, heat will help to stimulate blood flow, so after a tough workout, a soak in hot water feels amazing to relax sore muscles and help the blood circulation to remove lactic acid that might have built up.
Ideally, your water should be between 92 and 100 degrees F and as discussed, you’ll want to limit your time in the water to around 20 minutes. hot Tubs are superior to a simple bath due to their ability to maintain temperature more accurately, but a bathtub and some hot water will do in a pinch, and a hot shower might offer a simple alternative that lets you control the temperature a little more evenly.
Ice Baths
More popular with serious athletes, frankly, I’ve never taken an ice bath, and I honestly can’t think of anything much worse to subject yourself to. With that said, many people swear by them. I can easily see how an ice bath would quickly reduce your body temperature, and expedite the benefits discussed above, but the research I found didn’t really have any conclusive evidence backing this up. The biggest belief seemed to be that ice baths were useful to treat large areas (like the legs) all at once instead of in more localized areas with ice packs.
The healing logic is that once circulation has been slowed, and you’re out of the ice bath, when you warm back up, the healing process can occur more quickly since swelling has been reduced. The idea being that there’s nothing to limit the blood vessels from dilating and providing the area with needed oxygen and nutrients. In a sadistic way, it makes sense, but for me, I’m not sure I plan to rush into a bathtub full of ice anytime soon.
Ice / Cold Packs
A little more familiar and a lot less daunting are cold and ice packs. whether the cold is produced the old fashioned way; by a bag full of ice wrapped in a lightweight towel, or with a chemical cold pack, both are applied by holding the pack to the affected area for 20 minute intervals. For me, writing this article was an eye opener, as I would usually apply ice, let it re-freeze and then reapply the cold (frankly until I got bored and just put the ice away). The proper way is to apply ice for 20 minutes every 4-6 hours. Now that I understand what it’s doing to help my recovery, I realize that it’s important to allow the area to warm back up so that the blood flow into the area can occur an truly help the healing process.
Pro-tip: Sometimes Ice can be clunky and doesn’t really feel like it’s enveloping the entire injured area. Consider crushing it first, or better still, grab a bag of frozen peas and use it instead of ice. The small size of the peas will help surround a rounded part of the body like an elbow, or thigh and more evenly apply the cold. For an impromptu ice massage tool, consider freezing a bottled water and rolling it constantly over a sore area. Just make sure to keep it moving since this won’t be wrapped in a towel – say no to frostbite!
Heating Pads / Hot Packs / Chemical Heat
The cousin to the ice pack is the heating pad, hot water bottle or chemical hot pack. These allow you to apply heat to specific areas and can also be used while stretching lightly to ease muscle stiffness and increase blood flow. As an exercise tool, these are best used before a workout to help prepare the body for what you’re about to do, but can also be of use to relax muscles that are tight from stress or a healing injury. Just remember that ice is probably your best bet for the first 48 hours of an injury. If you are using heat, then the same 20 minute interval rule applies that should be observed with cold therapies, but no more than 3 times a day.
There are many other ways to apply hot and cold stimulus to the body, including saunas, steam rooms, and cryo-chambers, all of which will achieve the same results of adjusting your circulation to achieve a rehabilitative effect.
Contrast Therapy
Before we wrap this up, I’d be remiss if I didn’t talk about the idea of contrast therapy. This is the concept of using hot and cold therapies back to back to force your body to adapt quickly to the temperature and circulatory changes. This is most commonly achieved using water, as it’s possible to immerse a limb completely and maximize the speeds of the temperature changes. The good news is this is a relatively safe procedure, the bad news is there’s not much science supporting the idea that contrast therapy does much to increase recovery. If you still want to try this, feel free, be safe and follow the guidelines laid out above (no direct ice to skin contact, and avoid burning yourself!) and you should be fine – just don’t expect any miracles!
So what are your thoughts? Have you had any great experiences with temperature therapies? Have you found a secret technique that works wonders for you? I’d love to hear about it in the comments below.
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