Inactivity, exercise, and visceral fat. STRRIDE: a randomized, controlled study of exercise intensity and amount

Abstract

Despite the importance of randomized, dose-response studies for proper evaluation of effective clinical interventions, there have been no dose-response studies on the effects of exercise amount on abdominal obesity, a major risk factor for metabolic syndrome, diabetes, and cardiovascular disease. One hundred seventy-five sedentary, overweight men and women with mild to moderate dyslipidemia were randomly assigned to participate for 6 mo in a control group or for approximately 8 mo in one of three exercise groups: 1) low amount, moderate intensity, equivalent to walking 12 miles/wk (19.2 km) at 40-55% of peak oxygen consumption; 2) low amount, vigorous intensity, equivalent to jogging 12 miles/wk at 65-80% of peak oxygen consumption; or 3) high amount, vigorous intensity, equivalent to jogging 20 miles/wk (32.0 km). Computed tomography scans were analyzed for abdominal fat. Controls gained visceral fat (8.6 +/- 17.2%; P = 0.001). The equivalent of 11 miles of exercise per week, at either intensity, prevented significant accumulation of visceral fat. The highest amount of exercise resulted in decreased visceral (-6.9 +/- 20.8%; P = 0.038) and subcutaneous (-7.0 +/- 10.8%; P < 0.001) abdominal fat. Significant gains in visceral fat over only 6 mo emphasize the high cost of continued inactivity. A modest exercise program, consistent with recommendations from the Centers for Disease Control/American College of Sports Medicine (CDC/ACSM), prevented significant increases in visceral fat. Importantly, a modest increase over the CDC/ACSM exercise recommendations resulted in significant decreases in visceral, subcutaneous, and total abdominal fat without changes in caloric intake.

The ADRB3 Trp64Arg variant and obesity in African-American breast cancer cases

“…[48][49][50] Accumulation of visceral fat, more so than accumulation in other parts of the body, has been of clinical concern because of its potential contribution to risk of chronic conditions including diabetes, hyperinsulinemia and hypertension, 51 and to risk of postmenopausal breast cancer because of the production of estrogens in adipose tissue. There is growing evidence that physical activity can decrease the risk of breast cancer [52][53][54] and suggestive evidence that physical activity after breast cancer diagnosis may improve survival.…”

Validity of a new automated software program for visceral adipose tissue estimation

“…slice-O-matict (slice-O-matic version 4.2, Tomovision, Montreal, Canada) has been used to estimate visceral adipose tissue volumes in over 200 peer-reviewed scientific publications since 1991. [21][22][23][24][25][26] It has been validated against chemical analysis and other image analysis methods 21,27 and has been used as a reference standard method for comparison in several methodological reports. [28][29][30] The goal of this study was to compare the reliability and the validity of the new Hippo Fatt software against slice-O-matict software to assess its utility in measuring visceral and subcutaneous adipose tissues in epidemiological studies.…”

Adipogenesis is inhibited by brief, daily exposure to high-frequency, extremely low-magnitude mechanical signals

“…Thus, the inhibition of obesity and diabetes through exercise is achieved by metabolizing caloric intake via increased work expenditure (9) and a proportional reduction in hyperglycemia (10). This implies that the more strenuous and extended the exercise, the greater the benefit in metabolizing fat (11,12). In some contrast to this ''more is better'' perspective, it has recently been shown that short daily durations of high-frequency, extremely low-level mechanical signals, three orders of magnitude below those induced by exercise (13), can positively influence other physiologic systems, including bone (14) and muscle (15), once thought responsive only to intense physical challenges.…”