HOW TO GET INTO COLD WATER WHEN SWIMMING…
1. In the Canadian climate, swimming in cold water is an obstacle but there is one way to get into the water efficiently.
2. When entering the water, step into it confidently, allowing water to splash you slightly. Keep walking away from the shore without stopping; once you stop your body will realize what you are putting it through and go into flight mode, so avoid this at all costs.
3. Make sure water hits key areas on your body, such as your torso and wrists, before submerging. Having these areas in contact with the water will better acclimatize your body to the temperature once you are in. Finally, once you are sufficiently splashed and at a water level where you can immerse yourself all the way into the water.
4. Once submerged, keep your shoulders under water for at least two minutes. By then your body will be adjusted to the temperature and you can spend the rest of the day swimming without any regard for the temperature.
5. This is in complete contrast to the inch theory of getting in the water, in which you slowly wade into the water. Slowly walking as the water inches up bodily landmarks and then stopping to rest. Such as, waiting four minutes when the water hits your knee then moving onto thigh level etc. This strategy is slow and tedious and in the end less effective because once they do submerge many jump right back out of the water.
Source: Jacquelin Heichert