PeteM
04-22-2010, 10:53 PM
I had someone ask me what the benifits of ice water immersion in my training log, so this is what I came up with.
I think we can all agree that sitting in a tub of ice water would be rather un-appealing to most, and therefore, for someone to actually embark on such an adventure, there should be some significant benefit in the end.
Well, it all comes down to blood flow. Ultimately it is a way to trick our bodies into increasing the flow of blood to a specific area. As blood is the primary route of exchange for many factors involved in tissue repair, it would stand to reason that an increase in blood flow would be a good thing. Yes?
So what happens?
As you plunge yourself into the icy water, the various nerve fibres in your body will respond to the cold through an increase in their firing threshold. This response makes the whole progress somewhat more tolerable, as an increase in threshold requires a greater stimulus to fire. If a nerve doesn’t fire, then you don’t sense anything, and it won’t take very long to figure out why that is a desirable response. However, different nerves take different exposure time to respond.
Initially, there will be a slight cold sensation, for some it may be hard to detect, but it will be there, and typically lasts up to 3 min. The nerves in your body that are most sensitive to cold are the small light-touch, cold, and fibres that supply the muscle spindles. These will be the first to go numb. You can still feel.
Next, in a cruel twist of fate, your body will now progress to a sensation in complete opposite of cold, a burning feeling will begin, lasting 2-7 min. At this point, all your pain fibres are still chugging right along – unfortunately they are the endurance athletes of the nerve world. It’s the larger nerve fibres of proprioceptors and alpha motor nerves responding here.
Finally, at long last, and believe me, it will feel like a long time, around the 5-7min mark, the pain and postganglionic sympathetic nerve fibres respond to cold – at which point, cutaneous analgesia is achieved – you go numb. Yayyyyy!
So now your numb – now what?
Stay put for another 8-10 min. We’re looking for 15 min total. Its around the 15 min mark, the body will initiate what is called the Hunting response. Initially, in response to the cold, vasoconstriction will occour. But, then, to protect from cold damage, the body will open up blood flow, in an attempt to re-warm the cooled tissue. And thus, an increase in blood flow. This increase in blood flow will last as long as 3 hours.
So why the need to actually get in the tub with the ice – why can’t you just put an ice pack on the surface? Well the problem has to do with heat energy. Your body produces a lot, and it takes quite a lot of cold to absorb all that heat – especially when you’re talking about the large muscle mass of the lower limbs. For example, it takes exposure to 3.5C (38.4F), to get cooling to penetrate up to 4cm deep in the muscle tissue. Now I know that 4cm doesn’t seem all that deep, but tell you what. Take a straight pin, mark 5.5cm from the tip, (4cm muscle tissue penetration, 1.5 cm fat and skin), now push it into your leg until you reach 5.5cm, then tell me how deep it isn’t. Cooling will depend on subcutaneous fat, as that is a great insulator, but with less then ½” of subcutaneous fat, a skin fold pinch around 25-30mm, significant cooling can be achieved in 10min. Although a barrier to initial cooling, subcutaneous fat works to slow the contribution of ambient temperature to the re-warming of the tissue, increasing the duration of the increased blood flow.
So that’s it – why and ice bath is a benefit. I personally will use them when dealing with any type of injury – tear, strain etc. But they can also be used as a regular therapy. During my days playing football, that’s where you could find me, every day around 2:30 during the season, sitting in ice water up to my mid section. Kept me healthy.
I think we can all agree that sitting in a tub of ice water would be rather un-appealing to most, and therefore, for someone to actually embark on such an adventure, there should be some significant benefit in the end.
Well, it all comes down to blood flow. Ultimately it is a way to trick our bodies into increasing the flow of blood to a specific area. As blood is the primary route of exchange for many factors involved in tissue repair, it would stand to reason that an increase in blood flow would be a good thing. Yes?
So what happens?
As you plunge yourself into the icy water, the various nerve fibres in your body will respond to the cold through an increase in their firing threshold. This response makes the whole progress somewhat more tolerable, as an increase in threshold requires a greater stimulus to fire. If a nerve doesn’t fire, then you don’t sense anything, and it won’t take very long to figure out why that is a desirable response. However, different nerves take different exposure time to respond.
Initially, there will be a slight cold sensation, for some it may be hard to detect, but it will be there, and typically lasts up to 3 min. The nerves in your body that are most sensitive to cold are the small light-touch, cold, and fibres that supply the muscle spindles. These will be the first to go numb. You can still feel.
Next, in a cruel twist of fate, your body will now progress to a sensation in complete opposite of cold, a burning feeling will begin, lasting 2-7 min. At this point, all your pain fibres are still chugging right along – unfortunately they are the endurance athletes of the nerve world. It’s the larger nerve fibres of proprioceptors and alpha motor nerves responding here.
Finally, at long last, and believe me, it will feel like a long time, around the 5-7min mark, the pain and postganglionic sympathetic nerve fibres respond to cold – at which point, cutaneous analgesia is achieved – you go numb. Yayyyyy!
So now your numb – now what?
Stay put for another 8-10 min. We’re looking for 15 min total. Its around the 15 min mark, the body will initiate what is called the Hunting response. Initially, in response to the cold, vasoconstriction will occour. But, then, to protect from cold damage, the body will open up blood flow, in an attempt to re-warm the cooled tissue. And thus, an increase in blood flow. This increase in blood flow will last as long as 3 hours.
So why the need to actually get in the tub with the ice – why can’t you just put an ice pack on the surface? Well the problem has to do with heat energy. Your body produces a lot, and it takes quite a lot of cold to absorb all that heat – especially when you’re talking about the large muscle mass of the lower limbs. For example, it takes exposure to 3.5C (38.4F), to get cooling to penetrate up to 4cm deep in the muscle tissue. Now I know that 4cm doesn’t seem all that deep, but tell you what. Take a straight pin, mark 5.5cm from the tip, (4cm muscle tissue penetration, 1.5 cm fat and skin), now push it into your leg until you reach 5.5cm, then tell me how deep it isn’t. Cooling will depend on subcutaneous fat, as that is a great insulator, but with less then ½” of subcutaneous fat, a skin fold pinch around 25-30mm, significant cooling can be achieved in 10min. Although a barrier to initial cooling, subcutaneous fat works to slow the contribution of ambient temperature to the re-warming of the tissue, increasing the duration of the increased blood flow.
So that’s it – why and ice bath is a benefit. I personally will use them when dealing with any type of injury – tear, strain etc. But they can also be used as a regular therapy. During my days playing football, that’s where you could find me, every day around 2:30 during the season, sitting in ice water up to my mid section. Kept me healthy.