Are Fat Mass and Fitness Levels Related?
We take a look to see whether total body fat mass has an effect on aerobic capacity.
What is fitness?
One simple way to describe fitness is the bodies ability to recover after a bout of exercise.
Therefore, if you have just run 100 meters and then performed 10 burpees at your maximum effort, your level of fitness can be assessed by the time your body can recover enough for your two perform the exercises again.
However, many people associate a muscular, lean body as being ‘fit’.
A toned and sculpted body shows that you do plenty of exercise and eat correctly to increase muscular size and reduce fat levels.
Yet, you will see many professional athletes, some Olympians or even soldiers that do plenty of exercise but do not have chiseled abs or big biceps.
When we see people with lots fat mass the consensus is that they must be unfit.
So this begs the question whether fat mass and fitness are related?
Fat mass, fitness and abs
It is very easy to mix up good health, fitness and fat.
However, consider this.
A study by the University of Chester, UK, revealed the average speed, distance and time spent on playing field per game for professional rugby union players.
The data was collected from players of eight top professional rugby union teams which play in the Aviva Premiership rugby annual competition and offered an insight in to the demands of a player.
The ‘forwards’ tend to be the bigger players, or traditional so. Now, in the professional era the players are generally much bigger overall and position by size is much more blurred.
However, during a game of 80 minutes split in to two halves of 40 minutes the average distance covered by a ‘forward’ position player is 4.45km who would then run a maximum sprint pace of 23.7 km/h.
The game of rugby has very few break down of play, so the movement is fairly continuous and requires a high level of aerobic fitness.
With these aspects in mind, there has a been a study put in place that wanted to establish the relationship between body fat mass and body composition with levels of aerobic fitness.
In essence, is a person who is considered ‘fat’ less fit than a person that does not have a such a high percentage of fat mass.
Are the examples we have previously discussed merely extraordinary, or does the study eradicate the mindset that fat people are not as fit as thinner people?
The aim of the study set out was to examine how much influence body mass has on the VO2 max.
One study involved 129 children participants who had a wide spectrum of body types and composition.
A second study involved 31 women and their fitness levels while they were overweight and then again after significant weight loss.
What’s VO2 MAX?
VO2 Max is the maximum or optimum rate at which the heart, lungs, and muscles can effectively use oxygen during exercise, used as a way of measuring a person’s individual aerobic capacity.
How did they perform the study?
To see how well the participants’ bodies could effectively use oxygen during bouts of exercise they were subject to a treadmill test
Their body composition was assessed using dual energy X-ray absorptiometry and a four-compartment model.
What was discovered?
The results of the test demonstrate that free fat mass is strongly related to VO2max in that fat mass does not have any effect on VO2max.
Obesity in terms of Fat% is a better parameter than BMI for prediction of low VO2max.
This means, in general, those people who are fatter or who maintain a higher percentage of body fat are not able to effectively process are much oxygen.
Fatness and excess body weight do not necessarily imply a reduced ability to maximally consume oxygen, but excess fatness does have a detrimental effect on submaximal aerobic capacity.
With this in mind, this does then back the examples that are found in professional sport and contradict the notion and widely accepted though process that those who have lower levels of body fat are ‘fitter’.
‘Fitness’ icons or models are not a true representation of fitness levels and are merely a representation of aesthetic changes via a process of calorie control and muscle building which is different to aerobic capacity and aerobic recovery.
[Total body fat does not influence maximal aerobic capacity. Goran M, Fields DA, Hunter GR, Herd SL, Weinsier RL. Int J Obes Relat Metab Disord. 2000 Jul;24(7):841-8.]