Seasonal changes in amount and patterns of physical activity in women.
BACKGROUND
Environmental factors including seasonal changes are important to guide physical activity (PA) programs to achieve or sustain weight loss. The goal was to determine seasonal variability in the amount and patterns of free-living PA in women.


METHODS
PA was measured in 57 healthy women from metropolitan Nashville, TN, and surrounding counties (age: 20 to 54 years, body mass index: 17 to 48 kg/m2) using an accelerometer for 7 consecutive days during 3 seasons within 1 year. PA counts and energy expenditure (EE) were measured in a whole-room indirect calorimeter and used to model accelerometer output and to calculate daily EE and intensity of PA expressed as metabolic equivalents (METs).


RESULTS
PA was lower in winter than in summer (131+/-45 vs. 144+/-54x10(3) counts/d; P=.025) and in spring/fall (143+/-48x10(3) counts/d; P=.027). On weekends, PA was lower in winter than in summer by 22,652 counts/d (P=.008). In winter, women spent more time in sedentary activities than in summer (difference 35 min/d; P=.007) and less time in light activities (difference -29 min/d, P=.018) and moderate or vigorous activities (difference -6 min/d, P=.051).


CONCLUSIONS
Women living in the southeastern United States had lower PA levels in winter compared with summer and spring/fall, and the magnitude of this effect was greater on weekends than weekdays.
Energy Balance Laboratory, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
Maciej S
MS
Buchowski
Leena
L
Choi
Karen M
KM
Majchrzak
Sari
S
Acra
Charles E
CE
Mathews
Kong Y
KY
Chen
D000273:Adipose Tissue; D000328:Adult; D001823:Body Composition; D004734:Energy Metabolism; D005080:Exercise Test; D005260:Female; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity; D010101:Oxygen Consumption; D012621:Seasons; D012737:Sex Factors; D013714:Tennessee; D013997:Time Factors; D016138:Walking; D055815:Young Adult