title: Basal body temperature as a biomarker of healthy aging.
abstract: Scattered evidence indicates that a lower basal body temperature may be associated with prolonged health span, yet few studies have directly evaluated this relationship. We examined cross-sectional and longitudinal associations between early morning oral temperature (95.0-98.6 °F) and usual gait speed, endurance walk performance, fatigability, and grip strength in 762 non-frail men (52 %) and women aged 65-89 years participating in the Baltimore Longitudinal Study of Aging. Since excessive adiposity (body mass index ≥35 kg/m2or waist-to-height ratio ≥0.62) may alter temperature set point, associations were also examined within adiposity strata. Overall, controlling for age, race, sex, height, exercise, and adiposity, lower temperature was associated with faster gait speed, less time to walk 400 m quickly, and lower perceived exertion following 5-min of walking at 0.67 m/s (all p ≤ 0.02). In the non-adipose (N = 662), these associations were more robust (all p ≤ 0.006). Direction of association was reversed in the adipose (N = 100), but none attained significance (all p > 0.22). Over 2.2 years, basal temperature was not associated with functional change in the overall population or non-adipose. Among the adipose, lower baseline temperature was associated with greater decline in endurance walking performance (p = 0.006). In longitudinal analyses predicting future functional performance, low temperature in the non-adipose was associated with faster gait speed (p = 0.021) and less time to walk 400 m quickly (p = 0.003), whereas in the adipose, lower temperature was associated with slower gait speed (p = 0.05) and more time to walk 400 m (p = 0.008). In older adults, lower basal body temperature appears to be associated with healthy aging in the absence of excessive adiposity.
authors: Intramural Research Program National Institute on Aging, 3001 S. Hanover Street, 5th Floor, Baltimore, MD, 21225, USA. simonsickel@mail.nih.gov.
authors: Eleanor M
authors: EM
authors: Simonsick
authors: Joseph J. Zilber School of Public Health, University of Wisconsin-Madison, Wilwaukee, WI, USA.
authors: Helen C S
authors: HCS
authors: Meier
authors: Intramural Research Program National Institute on Aging, 3001 S. Hanover Street, 5th Floor, Baltimore, MD, 21225, USA.
authors: Nancy Chiles
authors: NC
authors: Shaffer
authors: Intramural Research Program National Institute on Aging, 3001 S. Hanover Street, 5th Floor, Baltimore, MD, 21225, USA.
authors: Stephanie A
authors: SA
authors: Studenski
authors: Intramural Research Program National Institute on Aging, 3001 S. Hanover Street, 5th Floor, Baltimore, MD, 21225, USA.
authors: Luigi
authors: L
authors: Ferrucci
mesh_terms: D050154:Adiposity / Q000502:physiology*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015142:Baltimore; D015992:Body Mass Index; D001831:Body Temperature / Q000502:physiology*; D003430:Cross-Sectional Studies; D005221:Fatigue / Q000378:metabolism; D005260:Female; D005684:Gait / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology; D016138:Walking / Q000502:physiology*
keywords: Aging; Body temperature; Excessive adiposity; Functional performance