Cardio on an empty stomach?
Everyone should experience and check the results in person. Far from settling the issue, I would like to point out some advantages and mistakes about it.
Aerobic exercise on an empty stomach can increase the amount of free fatty acids used as fuel. But, this is not because our glycogen deposits are empty in the morning. This would happen if we went to bed last night with low glycogen levels.
Almost all the energy we consume during sleep comes from free fatty acids. So glycogen deposits are not affected overnight. Next morning these fatty acids would be «free», ready as fuel for our cardio workout.
Low-intensity aerobic workout (50-70% of maximum) on an empty stomach, increases the insulin sensitivity after exercise, and the mobilization of fatty acids.
It is important to note that at a higher intensity (> 75% of maximum) we´ll get the opposite effect.
Moreover, not all are positive. Aerobic exercise is catabolic because it increases the production of cortisol. Cortisol levels are high in the morning, so this would lead to greater muscle wastage.
For greater efficiency of aerobic workout, your stomach should not be completely empty. I recommend a mixture: 5g of BCAA, 5g of glutamine and 5 grams of essential amino acids 15-30 minutes, before training.
Spending time on warming up and cooling down will improve your level of performance and accelerate your recovery process.
Research work by McNair (2000) and Knudson (2001) suggests that the use of dynamic stretches – slow controlled movements through the full range of motion – are the most appropriate exercises for the warm up. By contrast, static stretches are more appropriate for the cool down.
Warm up increases the blood flow to the muscles, allowing them to loosen up, which can raise the flow of oxygen to the muscle cells. Doing this gradually increases the body’s temperature. This then increases the speed and force of muscular contractions, because nerve impulses travel faster at higher body temperatures, and muscles become less stiff or more pliable.
Warm up also helps to gradually increase the heart rate and ensure that the demand made on the circulatory and metabolic systems is gradual as well. This initial part of your exercise session helps to improve neural function and coordination, protect major joints as it takes time to increase the supply of lubricating synovial fluid.
The warm up’s intensity should cause transpiration but not fatigue. The type of warm up needs to be appropriate for the activity planned. It also needs to be appropriate to the age range and fitness level of the participants.
The following examples cover a warm up:
walking or jogging to increase the body’s temperature (5-10 min)
dynamic stretches to reduce muscle stiffness (10-15 min)
specific stretches for muscles that will be used during exercises (10-15)
So in warming up thoroughly, we are preparing the body and the mind for the more energetic demands to come.
It is important to rehearse common movement patterns and skills which will be used in the match/competition. This will not only help to improve performance through ensuring the muscles are prepared for the task in hand, but will also help to improve coordination, reaction times and accuracy.
Examples of sports specific exercises include:
Cooling down after a workout is as important as warming up. After physical activity, your heart is still beating faster than normal, your body temperature is higher and your blood vessels are dilated. This means if you stop too fast, you could pass out or feel sick. A cool-down after physical activity allows a gradual decrease at the end of the episode.
It’s good to stretch when you’re cooling down because your limbs, muscles and joints are still warm. Stretching can help reduce the buildup of lactic acid, which can lead to muscles cramping and stiffness.
The cool down should consist of a gentle jog, decreasing in speed down to a walk followed by light static stretching. Remember to stretch all muscle groups used in the sport. Upper body muscles especially are often forgotten is sports such as football, soccer and rugby.
MCNAIR, P.J. et al. (2000) Stretching at the ankle joint: viscoelastic responses to holds and continuous passive motion. Medicine & Science in Sport and Exercise, 33 (3), p. 354-358
KNUDSON, D et al. (2001) Acute Effects of Stretching Are Not Evident in the Kinematics of the Vertical Jump, Journal of Strength & Conditioning Research, 15 (1), p. 98-101