1 In the interests of safety and hygiene please ensure that your Thermos flask is cleaned with warm water and washing-up liquid prior to initial use.  For best results from your flask, before use, pre-fill for about 3 minutes, using either hot water for hot drinks or cold water for chilled drinks.
Extrapolating these findings to the general population, the authors estimated that 8 million elderly persons nationwide have insomnia on any given day, more than 1 million new cases of insomnia develop each year, and symptoms resolve in nearly 1.3 million elderly persons annually.
There are two types of insomnia based on the regularity and duration of the sleep disturbance and daytime symptoms: 1  Short-term insomnia: This type of brief insomnia lasts for up to three months. 2  It occurs in 15 to 20 percent of people.