Thursday, December 6, 2007

Some obvious research? Fat people are not as fit

Maybe this is obvious to you, but I just came across this piece of research that found that the fatter you are the less fit you are likely to be. (It also found that stronger people had better bone mineral density). You could probably argue with some of the methodology but it is an interesting study as far as it goes.

Body Composition by DEXA and Its Association With Physical Fitness in 140 Conscripts

PURPOSE:: The aim of the study was to determine the body composition of healthy young men and to investigate whether there exists an association between body composition and physical fitness.
MATERIALS AND METHODS:: A prospective cohort study of 140 healthy male conscripts (mean age 19.8yr, SD 1.0 yr) was conducted. We examined subject characteristics, aerobic performance, and muscle strength, and we assessed body composition using dual-energy x-ray absorptiometry (DEXA). The association between total body composition and lower-limb composition and physical performance was investigated by linear regression.
RESULTS:: The mean body mass index (BMI) of the subjects was 24.6 kg.m (SD 4.7). Their mean bone mineral density (BMD) was 1.3 (SD 0.1), fat percentage (fat%) 22.6 (SD 9.7), lean mass 57.6 kg (SD 7.0), and bone mass 3.2 kg (SD 0.4) at the beginning of the military service. Fat percentage was significantly associated with 12-min running performance (P < style="font-weight: bold;">CONCLUSIONS:: DEXA measurement of the proportion of body fat is a useful tool to indirectly assess running performance and muscle strength in Finnish male conscripts. Increased fat mass and fat percentage were strong predictors of poorer physical fitness. Moreover, the relationship between muscle strength and BMD was confirmed. However, muscle mass did not predict muscle strength in our sample.

Ross Enamait had an interesting post on this idea the other day, in which he pointed out that
"a quick summary of the research suggests that cardiovascular fitness proves useful even to those who are carrying excess body fat. This research IS good news. Even those who currently have weight problems can realize the benefits of exercise.

This does not mean that we should overlook the dangers of obesity however. Do we really need Captain Obvious to save the day. Those with excess weight must still strive to lose it! Let’s not fool anyone and suggest that obesity is no longer an issue as long as you put in a little cardiovascular exercise. "

There was a related study the other day too:

Fitness, Fatness, and Cardiovascular Risk Factors in Type 2 Diabetes: Look AHEAD Study.

Purpose: Most studies comparing the effects of fitness and fatness on cardiovascular (CVD) risk have been done with young, healthy participants with low rates of obesity and high levels of fitness. The present study examined the association of cardiorespiratory fitness and obesity with CVD risk factors in an ethnically diverse sample of overweight/obese individuals with type 2 diabetes.

Method: Baseline data from Look AHEAD, a study of 5145 overweight or obese individuals with type 2 diabetes, were used to examine the association of BMI categories (overweight, class I, II, or III obesity) and cardiorespiratory fitness (assessed with a maximal graded exercise test and categorized by age- and gender-specific quintiles) on cardiovascular risk factors and on the odds of having hypertension, hyperlipidemia, or HbA1c >= 7%.

Results: BMI categories and fitness quintiles were highly associated with each other (P < style="font-weight: bold;">the heaviest participants being the least fit. Only 2-3% of participants had class III obesity and were in the two fittest quintiles or, conversely, were overweight and in the two least-fit quintiles. When fitness and BMI were included in the same model (adjusting for age, smoking, diabetes duration, and race), HbA1c, ankle/brachial index (ABI), and Framingham risk score were most strongly associated with fitness. Systolic blood pressure was most strongly associated with BMI category. Similar results occurred when waist circumference and fitness were considered together.

Conclusion: In this large, ethnically diverse sample of overweight/obese individuals with type 2 diabetes, fitness and fatness were highly related to each other but seemed to have different impact on specific CVD risk factors.

1 comment:

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I think that any of the men who do the things that you said can do in a sprint the athlete must be trained to work anaerobically throughout the race.!!