Thermogenic effect of food in physically well-trained elderly men

Exercise and Obesity

This paper reviews succinctly the evidence for a role of regular exercise in the prevention and the treatment of obesity and of its metabolic complications. Seventeen propositions relevant to an understanding of the topic are considered. The evidence suggests that regular exercise can be an important factor in the development of sustained negative energy balance conditions provided the volume of activity is high. This implies a program of low to moderate intensity exercise performed on an almost daily basis for at least one hour per session. To induce significant weight and fat losses and to treat overweight and obese patients, compliance to the program for several years becomes a necessity. Exercise increases lipid substrate oxidation and may favor carbohydrate intake for the same amount of energy intake. The acute effects of exercise on resting metabolic rate are well documented, but the long-term influences of exercise training seem to be small and are rapidly suppressed with the cessation of training. The obese benefits also from a regular exercise regimen in terms of improved insulin sensitivity, lipid and lipoprotein profile, and blood pressure, as well as reduced risk of death. Regular exercise, such as walking, is a healthy course of action for the overweight or the obese patients.

Validation of three predictive equations for basal metabolic rate in adults

Objective

To cross-validate three predictive set of equations for basal metabolic rate (BMR) developed by Schofield (Schofield database), Henry (Oxford database) and Cole (Oxford database) using mean values for age, weight, height and BMR of published studies.

Design

Literature review of studies published from 1985 to March 2002.

Setting

All studies selected used appropriate methods and followed conditions that met the criteria established for basal metabolism, were performed in healthy adults, and were not part of the Schofield or Oxford database.

Subjects

A total of 261 groups of men and women from 175 studies were selected and categorised in three age groups (18.5–29.9, 30.0–59.9, ≥60 years old) and three body mass index (BMI) groups (normal weight, overweight and obese).

Results

Linear regression and concordance correlation analysis showed that the three sets of equations had the same association and agreement with measured BMR, across gender, age, and BMI groups. The agreement of all equations was moderate for men and poor for women. The lowest mean squared prediction errors (MSPRs) were given by Henry equations in men and Cole equations in women. Henry and Cole equations gave lower values than Schofield equations, except for men over 60 years of age. Henry equations were the most accurate in men. None of the three equations performed consistently better in women.

Conclusion

These results support the use of Henry equations in men with a wide range of age and BMI. None of the proposed predictive equations seem to be appropriate to estimate BMR in women.

Supportive nutrition on recovery of metabolism, nutritional state, health-related quality of life, and exercise capacity after major surgery: a randomized study

BACKGROUND & AIMS

The aim of this study was to investigate whether specialized supportive enteral and parenteral feeding have superior effects compared to oral nutrition on recovery during long-term postoperative treatment of cancer patients with preoperative weight loss and reduced maximum exercise capacity.

METHODS

One hundred twenty-six patients referred for resection of the esophagus (n = 48), stomach (n = 28), or pancreas (n = 50) were considered to be included before operation. Included patients (n = 80) received supportive enteral or parenteral nutrition postoperatively at home corresponding to 1000 kcal/d until the patients did not wish to continue with artificial nutrition for any reason. Patients randomized to oral nutrition only served as control subjects. Caloric intake, body composition (dual-energy x-ray absorptiometry), and respiratory gas exchanges at rest and during exercise were measured including health-related quality of life.

RESULTS

Survival and hospital stay did not differ among the groups, whereas overall complications were higher on artificial nutrition (P < .05). Changes in resting energy expenditure and biochemical tests did not differ during follow-up among the groups. Body weight and whole body fat declined similarly over time in all groups (P < .005), whereas lean body mass was unchanged during follow-up compared to preoperative values. Maximum exercise capacity and maximum oxygen consumption were normalized within 6 months postoperatively in all groups. There was no difference in recovery of food intake among the groups. Parenteral feeding was associated with the highest rate of nutrition-related complications, whereas enteral feeding reduced quality of life most extensively.

CONCLUSION

After major surgery, specialized supportive enteral and parenteral nutrition are not superior to oral nutrition only when guided by a dietitian.

Effect of sustained resistance training on basal metabolic rate in older women

OBJECTIVE

To determine if basal metabolic rate (BMR) could be elevated in older women undertaking a program of progressive resistance exercise of up to 52-weeks duration.

DESIGN

Randomized controlled trial with subjects assigned to either a control (CO), high-intensity (HI), or low-intensity (LO) training group for 15 weeks. BMR, body composition, energy intake and expenditure, and muscle strength were assessed at baseline and after 15 weeks. Subjects were encouraged to continue in their assigned exercise group for an additional 37 weeks, after which time they were reevaluated.

SETTING

An exercise facility at a medical center.

SUBJECTS

Thirty-six community-dwelling healthy women aged 65 to 79 years.

INTERVENTION

Exercise groups performed three sets of 10 exercises, 3 days/week, at either 80% of one-repetition maximum (1-RM) for seven repetitions (HI) or 40% of 1-RM for 14 repetitions (LO).

MEASURES

BMR by indirect calorimetry, body composition by dual energy X-ray absorptiometry, energy intake and expenditure from 4-day dietary and activity records, and dynamic muscle strength by 1-RM.

RESULTS

Muscle strength increased, on average (+/- SEM), by 40 +/- 6% and 36 +/- 7% in the HI and LO groups after 15 weeks, respectively, compared with 4 +/- 1% in the nonexercising subjects (P = .0001). Fat mass decreased after 15 weeks in LO exercisers by 1.0 kg (P < .05), whereas there was a trend for fat-free mass (FFM) to increase in the HI group by 0.7 kg (P = .08). No change occurred in any group for BMR. From weeks 15 to 52, muscle strength increased a further 9 +/- 2% and 11 +/- 2% in HI and LO groups, respectively, compared with 3 +/- 1% in nonexercisers (P < .005). There was no change in BMR or any body composition parameter during this time period.

CONCLUSIONS

Neither training program significantly altered BMR and both produced only minimal changes in body composition. However, both the HI and LO exercise regimens resulted in similar and substantial gains in upper and lower body muscle strength that persisted over the course of the year. This suggests that either exercise regimen may prove an effective strategy for preventing frailty and maintaining functional independence in older adults.

The effects of aerobic and anaerobic exercise conditioning on resting metabolic rate and the thermic effect of a meal

This study examined resting metabolic rate (RMR) and thermic effect of a meal (TEM) among athletes who had participated in long-term anaerobic or aerobic exercise. Nine collegiate wrestlers were matched for age, weight, and fat-free weight with 9 collegiate swimmers. Preliminary testing included maximal oxygen consumption, maximal anaerobic capacity (MAnC) for both the arms and the legs, and percent body fat. On two separate occasions, RMR and TEM were measured using indirect calorimetry. VO2max was significantly higher in the swimmers while MAnC was significantly higher in the wrestlers for both the arms and the legs. RMR adjusted for fat-free weight was not significantly different between groups. The differences in total and percentage of TEM between the groups were not statistically significant, and there were no differences in baseline thyroid hormones. These data suggest that despite significant differences in VO2max and WAnT values following long-term aerobic and anaerobic exercise training, resting energy expenditure does not differ between these college athletes.

Regulation of energy expenditure in aging humans

The regulation of daily energy expenditure and its components in aging humans in considered in this review. Specifically, the effects of age on resting metabolic rate (RMR), the thermic effect of a meal, body composition, and the interaction of these variables with physical activity in both men and women are considered. The possible modulators of the age-related decline in RMR are examined by exploring the influence of alterations in body composition, physical activity, and the sodium-potassium pump. Thereafter, the status of energy requirements in healthy and diseased individuals is examined. New information is presented regarding the use of the doubly-labeled water technique to measure daily energy expenditure and its applicability to the determination of daily energy requirements in free-living older persons.

Failure to find increased TEM at rest and during exercise in aerobically trained and resistance trained subjects

This study examined the metabolic response to a 763-kcal mixed meal at rest and during 30 min of exercise at 50% maximal oxygen consumption (VO2max) in 8 aerobically trained (AT), 8 resistance trained (RT), and 8 untrained (UT) subjects. Oxygen consumption (VO2) was measured minute by minute during 30 min of exercise by indirect calorimetry on 2 nonconsecutive days (postabsorptive exercise, PA; and postprandial exercise, PP). Total VO2 consumed and total caloric expenditure during the PA and PP conditions were similar for the three groups, indicating that prior food intake did not affect energy expenditure during exercise. Consequently, TEM during exercise did not differ significantly among the groups. Respiratory exchange ratio (R) differed significantly only during the PA condition, with the AT group exhibiting significantly lower R values compared to the RT group, and significantly lower R values compared to the UT group. These data suggest that the consumption of a meal 30 min prior to exercise does not increase TEM during exercise in AT, RT, and UT subjects.

Relationship between aerobic fitness level and daily energy expenditure in weight-stable humans

The relationship between exercise and energy expenditure is unclear, with some suggestions that exercise leads to increased energy expenditure over and beyond the increase due to the exercise itself. In this cross-sectional study, we examined the relationships among aerobic fitness level, body composition, and total daily energy expenditure in 78 subjects. Daily energy expenditure (determined in a whole room calorimeter) was significantly correlated with both fat-free mass (FFM) and aerobic fitness (estimated from maximum aerobic capacity or VO2max). However, multiple-regression analysis demonstrated that, after accounting for FFM, VO2max did not explain a significant amount of the remaining variation in energy expenditure. In addition, the relationship between resting metabolic rate and both FFM and VO2max was evaluated using data from 214 weight-stable subjects analyzed retrospectively. The results were identical with the results obtained from the 78 subjects in that VO2max did not have effects independent of FFM on energy expenditure. We conclude that aerobic fitness does not have a direct effect on energy expenditure. However, it may have effects that are mediated through body composition, since in both populations studied here, VO2max was positively correlated with FFM and negatively correlated with adiposity.

Influence of age and endurance training on metabolic rate and hormones in healthy men

The associations among age, maximal aerobic capacity (VO2max), and body composition with resting metabolic rate (RMR), and fasting plasma hormones were examined in endurance-trained and untrained older and younger men. A higher RMR (approximately 6%; P less than 0.05), normalized per kilogram of fat-free weight (FFW), was found in endurance-trained younger and older men relative to untrained men. VO2max, independent of FFW, accounted for a significant portion of the variation in RMR. Fasting insulin and the fasting insulin-to-glucose ratio were higher in older men relative to younger men. This difference was diminished when differences in percent body fat were taken into account. Plasma thyroid hormones and glucagon were not associated with age, VO2max, or percent body fat. We conclude that endurance-trained and older men have a higher RMR than untrained younger and older men that is independent of differences in FFW. Plasma levels of thyroid hormones and glucagon are not influenced by age, VO2max, or adiposity in healthy nonobese men.

The thermic effect of feeding in older men: the importance of the sympathetic nervous system

We have previously published direct evidence that approximately one third of the thermic effect of feeding (TEF) in young healthy men can be accounted for by the meal-induced increment in sympathetic nervous system (SNS) activity. The elderly are known to have abnormal beta-adrenergic mechanisms and blunted responsiveness to sympathetic stimulation. Therefore, we postulated that the elderly might also have a blunted thermic response to a meal. In the present study, we evaluated the TEF in 25 young (age, 29.4 +/- 4.6 years) and 12 older (66.6 +/- 7.0 years), healthy weight-stable, untrained, nonsmoking men on no medications. Energy expenditure (ventilated hood system) and SNS activity (arterialized plasma catecholamine concentrations and norepinephrine [NE] kinetics) were measured before and following ingestion of an 800-kcal high-carbohydrate meal. At baseline, arterialized plasma NE concentration (P = .001) and appearance rate (P = .05) were 40% and 28% higher, respectively, in the elderly. Resting energy expenditure was related to fat-free mass (r = .54, P less than .01), and was 21% lower in the older men (P less than .01). Energy expenditure increased in both groups following the meal, but this TEF was 48% lower in the older men (P less than .001). This reduced TEF observed in the older subjects was associated with only a slight, nonsignificant, blunting of the SNS response to the meal. The TEF was related to the arterialized plasma NE appearance rate in the young, but not the older group. The TEF was unrelated to either glucose or insulin concentrations in either group.(ABSTRACT TRUNCATED AT 250 WORDS)