Larry Tucker and Travis Peterson
This study was conducted to determine if cardiorespiratory fitness at baseline, and changes in fitness, influence risk of weight gain (≥3 kg) over 20 months. Another aim was to ascertain if potential confounding factors, including age, education, strength training, energy intake, and weight, influence risk of weight gain.
In a prospective study of 257 women, fitness (VO2max) was assessed using a graded, maximal treadmill test at baseline and follow-up. Energy intake was measured using 7-day, weighed food records. Subjects were divided into quartiles based on fitness. Risk ratios were used to show the risk of weight gain among those who were fit at baseline compared with their counterparts.
Most women gained weight and 23% gained ≥3 kg. Mean VO2max was 35.7 ± 7.2 mL·kg−1·min−1. Women with low-fitness at baseline had 3.18 times (95% CI: 1.46 to 6.93) greater risk, and moderately fit women had 2.24 times (95% CI: 1.04 to 4.82) greater risk of weight gain than women in the high-fitness quartile. Adjusting for potential confounders had little effect on results.
High levels of fitness seem to help protect middle-aged women against weight gain, whereas low and moderate fitness increase risk of weight gain over time.
Lance E. Davidson, Larry Tucker and Travis Peterson
The influence of physical activity (PA) changes on risk of abdominal fat gain in midlife women has not been studied using objective measures and controlling for potentially confounding variables.
Changes in PA were assessed within a prospective cohort of 233 middle-age (40 ± 3 years), nonobese, nonsmoking, primarily Caucasian women by using accelerometers, worn continuously for 7 consecutive days at baseline and again at a 20 month follow-up. Weighed food intake diaries were completed on concurrent days. Bod Pod assessed total body fat. Abdominal fat was measured by abdominal circumference at the umbilicus.
Women who decreased PA gained abdominal fat across 20 months, while women who increased PA (F = 4.82, P = .009) did not. Change in PA remained an independent predictor of abdominal fat change after adjusting for potential confounders, including changes in total body fat and total energy intake. Compared with women who maintained or decreased PA, women who increased PA had approximately half the risk (RR = 0.52, 95% CI: 0.27, 0.98) of gaining abdominal fat.
Increasing daily physical activity may attenuate risk of abdominal fat gain in middle-age women independent of changes in total body fat or energy intake.
James D. LeCheminant, Larry A. Tucker, Bruce W. Bailey and Travis Peterson
To determine objectively measured intensity of physical activity (iPA) and its relationship to high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and the LDL/HDL ratio in women.
Two hundred seventy-two women (40.1 y) wore CSA-MTI model 7164 accelerometers to index intensity and volume of physical activity for 7 d. Blood lipids were measured at a certified laboratory.
HDL-C was 52.1 ± 10.1, 52.2 ± 9.7, and 56.1 ± 11.1 mg/dL for the low, medium, and high intensity groups (P = 0.040), LDL-C differences were not significant (P = 0.23). LDL/HDL differences were observed (P = 0.030) with specific differences between the low and high iPA groups (P = 0.006). For HDL-C and LDL/HDL, significant relationships remained with control of dietary fat and age but not body fat percentage or volume of activity.
High iPA had higher HDL-C levels and lower LDL/HDL ratios than low and medium iPA. The iPA was predictive of HDL-C partly due to its strong association with volume of activity and body fat percentage.