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Exercise and Metabolism
By Dr Lee Naylor
When asked the question, ‘why do you exercise?’ the majority of people respond with ‘to trim down and look good’.
Now that probably isn’t the best reason but it’s the truth and as long as you’re getting the health benefits by doing so, it isn’t altogether a bad response.
But just how does exercise make you look at yourself and see the weight dropping and assist in you becoming trimmer? The answer is associated with how your body breaks down and burns energy. And there are three types of exercise that affect your energy systems and your body’s metabolism. They are aerobic training, anaerobic training and resistance training and throughout the Olympic training programs you will perform and train within each of these energy systems.
Aerobic training is arguably seen as the most beneficial in metabolic change. The interesting facts about aerobic training, are that, it;
- Increases the number and size of energy burning molecules in muscle cells.
- Increases energy concentrations allowing your body increased time till exhaustion.
- Increases glycolysis activity and increases your lactate threshold allowing you to train harder.
Now in short this means that the body burns more energy while exercising and you’re able to exercise harder and for longer, that is, with higher intensity and duration, because of these metabolic changes. The most important factor to be cognisant of is that post endurance training you experience increased amount of lipid (fat) and carbohydrate catabolism (breakdown). The degree to which this is increased is significant, in some instances catabolism can increase by up to 20%. Now how good is that, even when your not exercises your bodies burning up excess energy.
Anaerobic exercise may not have as significant a role as aerobic training, however it does still have a role to play in metabolic response changes. The difference in anaerobic training is that because the intensity of the exercise is high, the body is unable to maintain a steady state. This means that some of the aerobic adaptations are not present.
The main change in anaerobic training is the body’s increased metabolic ability to regenerate ATP (energy). The changes in the metabolic rate of glycolysis are equivalent to that of aerobic training but obviously the exercise is in shorter bursts so the duration of energy burnt is less.
The intensity of the exercise does allow the body to breakdown muscle tissue and cells. This means that the bodies metabolic rate post exercise is still raised above that of an untrained metabolic rate. This change is less than experienced during aerobic training but may help to maintain muscle bulk in comparison to aerobic training so is still very beneficial.
The last form of training, resistance training, works on a deeper level to the previous two. In metabolic terms this may produce the greatest affect when used in conjunction with one of the other training methods.
During exercise the majority of energy is metabolized from the anaerobic energy stores of the Creatine Phosphate system. In terms of energy, metabolism it is not significantly different to anaerobic training. During the recovery phase its dramatic metabolic abilities are appreciated. Acute, post exercise, the body releases catabolic enzymes that breakdown the bodies muscle tissues. After restoring your bodies energies with food, insulin transports nutrients into the muscle cells causing an anabolic affect. During this period, whilst the body recovers, it adapts by increasing the size of the muscle. This increased muscle size now needs more energy to fuel its existence.
Now is everyone getting as excited about this as me? Can you see the metabolic benefits? Basically because you now have a greater muscle mass to provide energy to, the muscle itself utilises and burns larger amounts. When your body is at rest it metabolizes fat. So if you have more muscle to fuel and your bodies burning fat while you’re resting then, you’ll be metabolizing more fat. YES!!!
Now your getting excited about the prospect of exercise reducing adipose tissue (fat) and just exactly how it does it, get out there and get cracking.