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Fat distribution, especially increased visceral fat, may be as important as overall obesity in increasing risk of heart disease, type 2 diabetes and certain cancers. Risk of disease, as well as visceral fat, increases dramatically with age. Cross-sectional data suggest that increased risk of disease may be largely prevented if the age-related increase in visceral fat does not occur. The objective of this short review is to present data that show visceral fat increasing over 200% in men and 400% in women between the 3rd and 7th decades, show that a combination of weight gain, loss of muscle, and a shift from peripheral to central fat patterning contributes to this increase, and identify hormones that may be responsible for the shift. Finally, the review will show how participation in exercise can slow the age-related shift in visceral fat. [ABSTRACT FROM AUTHOR]

Objective: 31 magnetic resonance spectroscopy (MRS) was used to document long lasting losses in muscle oxidative capacity after bouts of intense endurance exercise. Methods: The subject was a 34 year old highly fit female cyclist (Vo2MAX = 53.3 mI/kg/min). Over a five month period, she participated in three separate intense bouts of acute unaccustomed exercise. 31P MRS measurements were performed seven weeks after the first bout and every Iwo weeks for 14 more weeks. In all cases, 31P MRS measurements followed three days after each bout. Results: The subject showed a decreased ability to generate ATP from oxidative phosphorylation and an increased reliance on anaerobic ATP production during the 70% and 100% maximal voluntary contractions after the exercise bouts. Increased rates of fatigue and increased indicators of exercise difficulty also accompanied these reductions in muscle oxidative capacity. Increased oxidative and anaerobic ATP production were needed to maintain the work level during a submaximal 45% maximal voluntary contraction exercise. Conclusions: Acute increases in intensity accompanied by a change in exercise mode can influence the ability of muscle to generate ATP. The muscles were less economical and required more ATP to generate force during the submaximal exercises. During the maximal exercises, the muscle's mitochondria showed a reduced oxidative capacity. However, these reductions in oxidative capacity at the muscle level were not associated with changes in whole body maximal oxygen uptake. Finally, these reductions in muscular oxidative capacity were accompanied by increased rates of anaerobic ATP production, fatigue, and indicators of exercise difficulty. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Whole body air-displacement plethysmography (BOD POD), a new body composition technique, was validated against hydrodensitometry (UWW) in 67 women wearing a one-piece swimsuit (OP) who represent a wide range of body fatness and age. Additionally, the effect of trapped isothermic air in clothing while in the BOD POD was examined by comparing different clothing schemes (a one-piece swimsuit (OP), two-piece swimsuit (TP), a hospital gown (HG), and a hospital gown previously included in a volume calibration (GC)) in a subset of 25 women. DESIGN: Cross-sectional data analysis. SUBJECTS: 67 healthy Caucasian females. MEASUREMENTS: Body density g/cm³ (Db) by BOD POD and UWW. RESULTS: In 67 females UWW Db (1.030±0.020 g/cm³) was higher (P<0.01) than BOD POD Db (1.028±0.020 g/cm³). This is a difference of 1.0% fat. The R² was 0.94, SEE was 0.005 g/cm³ and the regression between Db by UWW and BOD POB did not significantly deviate from the line of identity. In the subset group of 25 subjects, OP Db (1.040±0.014 g/cm³) and TP Db (1.040±0.014 g/cm³) were significantly lower (P<0.01) than UWW Db (1.044±0.014 g/cm³) or a difference of 1.9% fat. The R² was 0.86 and the SEE was 0.005 g/cm³ and the regression between Db by UWW and both OP and TP did not significantly deviate from the line of identity. HG Db (1.056±0.016 g/cm³) and GC Db (1.037²0.016 g/cm³) were significantly different (P<0.01) from UWW Db (1.044±0.014 g/cm³). This difference in density translates to a difference of 5.5% and 3.2% fat respectively. The regression between Db by UWW and both HG and GC significantly deviated from the line of identity. CONCLUSION: This study supports the use of the BOD POD as a substitute for UWW. However, caution should be made in using the BOD POD if subjects are clothed in anything other than a tight fitting swimsuit. [ABSTRACT FROM AUTHOR]

The objective of this commentary is to remark on the impact, exercise intensity has on energy expenditure and its potential for body weight control. Exercise intensity can favorably impact on energy expenditure in a number of ways. First, exercise-associated energy expenditure is increased by decreasing exercise efficiency and increasing work rate. Second, resistance training that increases muscle mass, in turn increases resting energy expenditure. Third, aerobic exercise >70% VO2max, increases resting energy expenditure separate from any change in muscle mass. High-intensity exercise training has the added benefit of improving fitness, thus making low-intensity exercise less difficult and more easily tolerated. Although continuous intense exercise is difficult to maintain for extended periods of time, intense interval exercise can be easily endured and may be an important adjunct to lifestyle modifications for body weight control. [ABSTRACT FROM AUTHOR]