Cool ambient and water temperature can have a positive impact on your health, primarily by boosting antioxidant levels and promoting better sleep.
Studies have found that in general, the optimal temperature for sleep is quite cool, around 60 to 68 degrees Fahrenheit. For some, temperatures that fall too far below or above this range can lead to restlessness.
Temperatures in this range, it seems, help facilitate the decrease in core body temperature that in turn initiates sleepiness. A growing number of studies are finding that temperature regulation plays a role in many cases of chronic insomnia. Researchers have shown, for example, that insomniacs tend to have a warmer core body temperature than normal sleepers just before bed, which leads to heightened arousal and a struggle to fall asleep as the body tries to reset its internal thermostat.
For normal sleepers, the drop in core temperature
is marked by an increase in temperature in the hands
and feet, as the blood vessels dilate and the body
radiates heat. Studies show that for troubled sleepers,
a cool room and a hot-water bottle placed at the feet,
which rapidly dilates blood vessels, can push the
internal thermostat to a better setting.
Cold showers may increase glutathione one of the bodys most powerful endegenous antioxidants. In fact, many of the antioxidants we ingest orally work by helping the body produce glutathione. While the body can make its own glutathione from other nutrients, if we try to take a glutathione pill, our bodies just cant seem to utilize it. Encouragingly, a study of winter swimmers hints that cold water therapy can stimulate increases in glutathione levels.
David Perlmutter, M.D., author of The Better Brain Book writes Glutathione is perhaps the most effective and beneficial antioxidant in the nervous system and has the added benefit of enhancing mitochondrial energy production.
Ray Sahelian, a medical doctor and author, writes Glutathione peroxidase plays a variety of roles in cells, including DNA synthesis and repair, metabolism of toxins and carcinogens, enhancement of the immune system, and prevention of fat oxidation Brain glutathione levels have been found to be lower in patients with Parkinsons disease.
One study followed ten healthy subjects who swam regularly in cold water, and compared their glutathione levels to non-winter swimmers. They found two things:
1. Immmediately after swimming they had an inflated amount of oxidized glutathione to total glutathione.
2. At baseline, their reduced glutathione was greater while their oxidized glutathione was less than non-winter swimmers.
What does this mean? This is good. If you will recall some high school chemistry, oxidation is a rusting-like process in which a cell gets an electron stolen from it, becoming damaged. Antioxidants sacrifice their own electrons for the benefit of the cells. Therefore, although immediately after a cold shower your antioxidant glutathione becomes oxidized, when you return to baseline the protective form will be more plentiful than it was.
Think of it as working out; your muscles are a bit weak immediately afterwards, but stronger when you recover. The researchers write This can be viewed as an adaptation to repeated oxidative stress, and is postulated as mechanism for body hardening. Hardening is the exposure to a natural, e.g., thermal stimulus, resulting in an increased tolerance to stress, e.g., diseases. Exposure to repeated intensive short-term cold stimuli is often applied in hydrotherapy, which is used in physical medicine for hardening.