Each of us believes it to be a duty to refresh oneself on a hot day by jumping into some water body, but we should be careful here. The enquiry is that swimming in chilly water on a hot day is rather dangerous, especially if you stayed on the sun for quite a bit before going for a swim. The thing is that once overexposed to sun you can provoke spasms in the heart vessels. Therefore, you should cool down in the shadow a bit at first and only then rush into water. Full story