Can 98.6 ~ Be a Fever in Disguise?

Body temperature drops as age advances, this study suggests. P A T R I C I A H I G G I N S

Evidence increases that the well elderly person's temperature is of- ten below the "norma l" 98.6~ (36 ~ C) and that body temperature decreases with increasing age.

The study reported here showed an average, or mean, tempera ture of 97.7 ~ F in a group of 60 well men and women over the age of 65. Therefore, even a tempera ture of 98 .6~ might indicate beginning signs of illness in an elderly per- son.

I n a high proportion of older adults, autonomic nerve function declines and neural cell density de- creases. These changes affect the blood supply and the hypothala- mus, which is the site of thermoreg- ulation. The combined effects of low peripheral blood flow and inad- equate temperature regulation place older adults at risk for devel- oping hyp0thermia.

The aged also may suffer from unintentional or accidental hypo- thermia(1,2). This danger can arise from external exposure to cold or inadequate clothing. Accidental hypothermia is also influenced by internal factors that impair heat

Patricia ttiggins, RN, MSN, is an assistant professor at the College of Nursing, Univer- sity of New Mexico, Albuquerque.

She extends thanks to Jessie Pergrin, RN, PhD, director of the project on which her article is based, and to Julia Thornbury, RN, MSN, for reviewing the article.

production an d regulation (see box entitled Factors Affecting Body Tempera ture) .

For the preceding reasons, it ap- pears unwise for nurses to continue using the 98 .6~ value as part of their data base to determine well- ness or illness.

Study: Sample and Methods

A descriptive study was con- ducted to determine the normal tempera ture of the well adult over age 65. The oral glass thermometer was the testing instrument used.

The thermometer was calibrat for accuracy before and after t data were collected.

Data were collected in three se- nior citizens' centers in Tucson, Ar- izona, from 9:00 A.M. to 12:00 noon. This t ime was selected b e - cause body tempera ture generally peaks in the late morning(3). This circadian rhythm is particularly re- lated to activities affecting metabo- lism.

The sample consisted of 60 well adults (33 women, 27 men) be- tween the ages of 65 and 90. All

ing,

Factors Affecting Measurement of Body Temperature Body Temperature

�9 metabolism

�9 adipose tissue

�9 drugs*

�9 muscle activity

�9 chewing

�9 environmental temperature

�9 food

�9 disease processes

�9 change of position (sitting to ly- standing, turning)

Cad Reinhold August Wundedich first measured the typical curve in body temperature of typhoid fever patients in 1870. A number of studies have es- tablished 98.6~ (360C) as the norm, but the physiological basis for main- taining normal body temperature has emerged slowly over the past 100 years and is based on the identifica- tion of the neural transmitters acetyl- choline, in 1936; norsdrenalin, in 1956; and serotonin, in 1928. In 1965,

�9 cigarette smoking

�9 temperature of fluids

�9 A*mong the drugs that may raise body temperature are norepinephrine, serotonin, hydrocortisone, caffeine, amphetamines, and low doses of narcotics.

Among drugs that may lower body ~tern- perature are acetylcholine, dopamine, anti- pyretics, phenothiazines, reserpine, barbi- turates, alcohol, marijuana, meperidine, and high doses of narcotics.

SOURCE: Lomax, Peter, and Edward Schon- baum, ed. Body Temperature: Regulation, Drug Effects and TherapeutiC Implications. Vol. 16. (Modem Pharmacology-ToxiColo- gy Series). New York: Marcel Dekker, Inc., 1979.

serotonin's role as a transmitter in thermoregulation was discovered, In t 976, Myers reported the presence of calcium and sodium in the posterior hypothaJamus. When these cations are in balance the temperature is nor- mal.

~ s : Benzinger, T. H., ed. (Bench. mark Papers in Human Physiology.) Tern perature: Part 1. Arts end Concepts. 1977 New York, Academic Press.

Myers, R. D. Neurochemicel mechanism of two hypothalamic temperature contr~ systems. I~ Temperature: Part 2. Therm Homeostasis, ed. by T. H. Benzinger, New York. Academic Press, 1977.

Geriatric Nursing March/April 1983 101

had consented to part icipate. Sub- jects were asked a series of ques- tions regarding their health. Well- ness was considered the absence of an active disease process and no in- take of drugs affecting t empera tu re (antibiotics, reserpine, thyroid, an- t ipyretics) for two weeks before the study.

Each subject sat quietly in a chair for 15 minutes without smok- ing, chewing, or drinking, all activ- ities that influence body tempera- ture. Each subject 's oral t empera- ture was then taken once for I0 minutes, a period based on Cran- ston's s ta tement that oral t empera - ture should be taken for eight to n ine minutes to obtain an accura te reading(4).

Results and Implications

In the total sample of 60 subjects ranging f rom the age of 65 to 90 years, the average t empera tu re was 97.9"F, or 0.7 ~ below the "nor- ma l " 98.6~ The 33 women had an average t empera tu re of 98.1 ~ F; the 27 men had an average temper- a ture of 97.9 ~ F.

When the subjects were placed in age ranges by half decade (65 to 69, 70 to 74, and so forth), mean t empera tu re decreased with in- creasing age (see Table 1). The mean t empera tu re for all age groups was below 98.6" F.

Table 2 shows the mean temper- a ture in relation to age by half de- cade for men and women. In the 65 to 74 age group, women had a Iow- er mean t empera tu re than men by only 0.2"F. Tempera tu r e for both sex groups did not change between ages 65 and 74, but t empera tu re decreased for both groups between 75 and 90. Af ter 74, women had a higher mean t empera tu re than men.

The sample size was small for each age range. However, the da ta show tha t t empera tu re for both sexes in this sample was lower than 98 .6"F and decreased with age.

Knowing tha t the elderly have lower body tempera tures has impli- cations for practice. I t encourages nurses to be more critical in physi- cal assessment and in planning the

Table 1. Age and Mean Temperature for All Subjects (n = 6 0 )

Age 3" ~ Range ~'~ '~

65-69 ~ )

70-74 4 ~ liar 75-79

80-90

Number of Subjects

12 ~ 98.3

14 98.2

17 97.8

17 97.5

Mean o F

Table 2. Mean Temperature in Relation to Age by Decade for Men ( N = 2 7 ) and Women ( N = 3 3 )

Age Range

65-69

70-74

75-79

8 0 - 9 0

Number of Men

6

2

10

9

Mean ~ F For Men

98.4

98.4

97.7

97.1

Number of Women

n = 6

n=12

n= 7

n = 8

Mean * F For Women

98.2

98.2

98.0

97.9

specifics of care. Any elevation of t empera tu re to 98.6~ or above, par t icular ly in persons over 75, should raise the suspicion of fever and prompt a search for the un- derlying cause.

Nurses need to encourage older people to keep their rooms wa rmer in cold weather. Limited and often fixed incomes may make higher thermosta ts seem a luxur); to the elderly. In some states, however, extra heat ing allowances a re avail- able to senior citizens "from state and municipal governments. There is a need to teach the elderly to wear warm, light, nonrestrictive clothing. Hypo the rmia is more likely at night, so extra bedding, perhaps a night cap, and an electric

blanket are desirable. I f an elder 's nutrit ion is inade-

quate, this adds to the risk of hypo- thermia. Referra ls for assistance in securing food s tamps m a y be in or- der. Clients need to be informed that al though alcohol m a y increase the feeling of warmth it also in-

c reases heat loss f rom the body.

References I, Exton-Smith, A.N. Medicine in old age. Acci-

dental hypothermia. Br.Med.J. 4:727-729, Dec. 1973.

2. Kolanowski, Ann, and Gunter , Laurie. Hypo- thetmia in the elderly. Geriatr.Nurs. 2:362- 365, Sept.-Oct. 1981.

3. Sims-Will iams, A. J . Tempera ture taking with glass thermometers: a review. J.Adv.Nurs. 1:481-493, Nov. 1976.

4. Cranston, W. I., and others. Oral , rectal and oesophcgeal temperatures aria some factors af- fecting them in man. J.Physiol. 126:347-358, Nov. 1954.

1 0 2 Ger ia t r ic Nur s ing M a r c h / A p r i l 1983