The temperature of bath water is not often considered as a major safety hazard to adults, but to the elderly with impaired senses and slower movement, it is a significant risk. Bathing in water that is too hot obviously runs the risk of burns but there is also danger in water that is hot yet not hot enough to burn the skin and on the other end cold bath water. Some of these bath water temperature risks applies to younger adults, children and infants as well.
Ideal Bath Water Temperature
Personal preference for the temperature of bath water is one major factor in deciding the levels that are ideal for the individual. Bath water temperature should be just a degree or two high than normal body temperature. However, for some people this may not be hot enough. It is important to realize that from about 39 degrees Celsius (102F) upwards, the temperature of the bath water can have a physiological effect on the body. Some of these effects can compromise a person’s health.
Remember that the body perceives temperature by comparison – to the environmental temperature and internal temperature. Ensure that the bathroom air temperature is within a comfortable range and that they body has adapted to it before judging the bath water temperature. If there is no major difference between the bathroom air temperature and bath water temperature, the body does not have to undertake as many changes to compensate for the temperature shift.
Very Hot Bath Water
Water that is too hot can cause burns. It is dependent on the fragility of the skin as well as the duration of exposure. Ideally, the hot water coming out of the faucet should be somewhere in the 46 to 50 degrees Celsius (114F to 122F) range. This is too hot to bathe with but after mixing with cold water and heat loss into the environment, it can be brought down to a sufficiently comfortable level. Temperatures from 60 to 70 degrees Celsius (140F to 158F) onwards can cause very serious burns even with short term exposure.
Hot Bath Water
For the elderly who are living alone, who may have impaired temperature perception and are physically impaired to some degree from quickly responding to a sudden surge of hot water, the thermostat should be lowered even further. This ensures that water coming out of the hot water faucet alone does not exceed 42 degrees Celsius (about 107F). Although water at this level may not cause burns, it can still affect the body in several ways. Once again the duration of exposure and the ability to move out of the water can determine the degree of risk.
Hot water causes the blood vessels on the surface of the skin to dilate. This means that more blood flows to the body surface and away from the internal organs. It is the body’s way of dissipating heat to keep the core body temperature within normal levels. Excessive blood flow to the skin and subsequent compensatory mechanisms can cause cardiovascular strain. At bath water temperatures of 39 degrees Celsius (102F), the heart has to start working harder which can be a problem to the elderly.
Cold Bath Water
Just as dangerous as heat is cold bath water. Cold causes the superficial blood vessels to narrow increasing the blood flow to the internal organs and back to the heart. A greater returning blood volume means that the heart has to also work harder to move this blood around and the deeper blood vessels have to relax to keep the blood pressure within a normal range. By bathing in water that is colder than the core body temperature, body heat is lost to the environment. Immersing in water even a degree or two lower than the core body temperature can lead to hypothermia in the elderly. This is a major environmental risk among the elderly for various reasons and bathing in cold water can exacerbate the condition further.
Last Updated: November 30th, 2012 by Chris